Green Analytical Chemistry

A green chemical analysis of ethanol using a smart phone

This research presents a novel method for measuring ethanol concentrations using a smartphone. The method involves an oxidation reaction with potassium dichromate and concentrated sulfuric acid, resulting in a green-blue color formation. The color intensity, corresponding to ethanol concentrations ranging from 0 to 100%, was captured using a smartphone camera within a specialized photography box. The images were then analyzed using a specific application, converting the color signal into an absorbance value. The calibration curve demonstrated excellent linearity in the range of 0-0.55 v/v % and its detection limit is 0.01 v/v%, with a correlation coefficient exceeding 0.995. The method was successfully applied to measure ethanol in real samples, including ordinary rose water and a bitter wheat drink.•The method is inexpensive.•The method is rapid.•The method is green.

Evaluating the effectiveness of different household washing techniques for removal of insecticides from spinach and chickpea leaves by micellar liquid chromatography

In the past few decades, the employment of green analytical approaches in chromatographic method development has attracted the analytical separation community. The greenness of the developed method depends upon the toxicity of solvents and the amount of generated post-analysis waste generated. In this concern, micellar liquid chromatography (MLC) is a simple and rapid technique that generates very low toxic waste compared to traditional chromatographic pesticide detection methods. Here, MLC method has been validated and applied for the determination of monocrotofos (MCF), imidacloprid (ICP), dimethoate (DM) and profenofos (PFF) in spinach and chickpea leaves. The optimized mobile phase was 0.065 M SDS-2 % 1-propanol, 0.01 M NaH2PO4 buffered to pH 7. A C18 column was used for separation with a flow rate of 1 mL/min. The developed method has been validated following the guidelines of SANTE/11,312/2021 and ICH guidelines for; limit of quantification (0.05-0.20 mg/kg), linearity (r2> 0.997-0.999), precision (<6.3 %), accuracy (96.3 %-99.8 %) and robustness (<6) in real samples. ICP and MCF, apart from DM and PFF, were detected in the present work. After detecting insecticides in spinach and chickpea leaves both were washed with different household chemicals i.e. normal, lukewarm, common salt, lemon juice water and commercial ozonizer. Based on five washing techniques with insecticide concentration time intervals reduction rates were calculated for each washing treatment. The results show that lemon juice, common salt water, and ozonizer can be used as washing techniques for the reduction of superficial and systematic residues of ICP and MCF. Common salt and lemon juice water were better for washing over vinegar and potassium permanganate (KMnO4) as they enhance the colour of the green leafy vegetables and are available in every Indian kitchen. They can be easily used by lower socioeconomic classes who cannot afford KMnO4 and vinegar.

Automated H2O2 monitoring during photo-Fenton processes using an Arduino self-assembled automatic system

A cheap and easy to use Arduino self-assembled automatic system was employed to continuously monitor the hydrogen peroxide consumption during the photo-Fenton degradation of caffeine, selected as model target compound. The automatic system made it possible to measure the H2O2 concentration in the reaction cell via a colorimetric reaction and to take samples for HPLC analysis minimising the operator manual intervention and exposure to UV radiation. The obtained results were compared in terms of LOD and LOQ with H2O2 measurements manually performed using UV-Vis spectrophotometry, evidencing better analytical performance when using the automatic system; LOD and LOQ were respectively 0.032 mM and 0.106 mM for the automatic system against 0.064 mM and 0.213 mM for UV-Vis spectrophotometry. Furthermore, the photo-Fenton treatment was optimised by means of a Design of Experiments (DoE) investigating the effect of added H2O2 concentration, iron concentration and caffeine initial concentration on system performances. The use of the automatic device for such monitoring provided several advantages: automation (with consequent reduction of the workload), measurement increased precision, reduced reagents consumption and waste production in agreement with the principles of Green Analytical Chemistry.

A green, fluorescent probe employing erythrosine-B for tracing the accidental administration of levamisole in milk and plasma samples

A simple and sensitive fluorescent probe has been developed and optimized to detect the non-intentional administration of levamisole (LVM). LVM is used as an anthelmintic therapy in cows, and hence, its residues appear in the drained milk until 60 hours after administering the drug. Meanwhile, levamisole is known to be an adulterant to cocaine and could be detected in addicts' plasma samples. Owing to its severe side effects, including agranulocytosis, which is lethal in many cases, detection and quantification of LVM in milk and plasma samples are of utmost importance. Therefore, a sensitive and selective analytical method is required for this purpose. This work develops a highly fluorescent probe obtained through the reaction between LVM and erythrosine-B in an acidic medium, where the produced ion pair complex has been measured at 553 nm after excitation at 528 nm. The proposed method provides linearity over the concentration range of 0.5-2.0 μg mL-1 for LVM, with a corresponding detection and quantitation limit of 0.5 and 0.3 μg mL-1. Full validation was performed, permitting the application of the suggested method to perform simple extraction steps. All the applied procedures followed the guidelines offered by green analytical chemistry, where the Green Analytical Procedure Index (GAPI) assessed the greenness of the proposed tool, and the yielded pictograms proved the eco-friendliness of the offered tool.

Insights into the sustainability of liquid chromatographic methods for favipiravir bioanalysis: a comparative study

The introduction of favipiravir as a broad-spectrum antiviral agent, particularly in treating influenza and exploring its potential against COVID-19, emphasizes the necessity for efficient analytical methods. Liquid chromatography has emerged as a commonly utilized technique for quantifying favipiravir in biological fluids. However, the environmental and health concerns linked to classical analytical methods mean a transition toward green analytical chemistry is required. This study investigates the environmental impact of 19 liquid chromatographic methods utilized in the bioanalysis of favipiravir. Recognizing the importance of eco-friendly practices in pharmaceutical analysis, the study employs three widely accepted greenness assessment tools: Analytical Eco-Scale (AES), Green Analytical Procedure Index (GAPI), and Analytical Greenness Calculator (AGREE). Moreover, it incorporates a comprehensive evaluation on a global scale utilizing the whiteness assessment tool Red-Green-Blue 12 (RGB 12). The comprehensive evaluation aims to extend beyond traditional validation criteria and considerations of green chemistry, providing insights into the development of practically efficient, eco-friendly and economical analytical methods for favipiravir determination. This study emphasizes the necessity of planning for the environmental impact and overall sustainability of analytical methods before laboratory trials. Additionally, the integration of greenness/whiteness evaluation in method validation protocols is strongly advocated, emphasizing the importance of critical and global evaluations in analytical chemistry.

Biochar-based polymeric film as sustainable and efficient sorptive phase for preconcentration of steroid hormones in environmental waters and wastewaters

BACKGROUND

The environmental impact of sample preparation should be minimized through simplification of the procedures and the use of natural, renewable and/or reusable materials. In such scenario, thin-film microextraction fulfils the former criteria, as it enables few steps and miniaturization, thus small amount of extraction phase. At the same time, the use of sorbents such as biochars obtained from biomass waste is even more promoted due to their availability at low cost and increased life-cycle in a circular economy vision. However, it is not always easy to combine these criteria in sample preparation.

RESULTS

A thin film microextraction was developed for the determination of steroids in aqueous samples, entailing a membrane made of cellulose triacetate and a wood-derived biochar (Nuchar®) as carbon precursor. Different characterization techniques showed the successful preparation, whereas the sorption kinetics experiments demonstrated that biochar is responsible for the extraction with the polymer acting as a smart support. After a study about membranes' composition in terms of biochar amounts (4 %, 10 %, 16 % wt) and type of synthesis set up, the ceramic 3D-mold was selected, achieving reproducible and ready-to-use membranes with composition fixed as 10 %. Different elution conditions, viz. type and time of agitation, type, composition and volume of eluent, were evaluated. The final microextraction followed by HPLC-MS/MS quantification was successfully validated in river and wastewater treatment plant effluent samples in terms of accuracy (R% 64-123 %, RSD<19 % in river; R% 61-118 %, RSD <18 % in effluent, n = 4), sensitivity (MQLs 0.2-8.5 ng L-1) and robustness.

SIGNIFICANCE

This novel biochar-based polymeric film proved to be a valid and sustainable sorbent, in terms of extraction capability, ease of preparation and greenness. By comparison with literature and the greenness evaluation with the most recent metric tools, this method expands the potential applicability of the thin-film microextraction and opens up innovative scenarios for sustainable procedures entailing the use of biochars entrapped in bio-polymers.

Determination of trace chelating carboxylic acids in rice by green extraction combined with liquid chromatography-mass spectrometry analysis and its application in the evaluation of old and new rice

RATIONALE

Accurate identification of old rice samples from new ones benefits their market circulation and consumers. However, the current detection methods are still not satisfactory because of their insufficient accuracy or (and) time-consuming process.

METHODS

Chelating carboxylic acids (CCAs) were selectively extracted from rice, by stirring with chelating resin and a dilute Na2CO3 solution. The green analytical chemistry guidelines for sample preparation were investigated by using the green chemistry calculator AGREE prep. The extractant was determined by liquid chromatography-mass spectrometry (LC/MS), and statistical analysis of the analytical data was carried out to evaluate the significance of the difference by ChiPlot.

RESULTS

The limit of quantitation for the CCAs is in the range of 1 to 50 ng/mL, with a reasonable reproducibility. The CCAs in 23 rice samples were determined within a wide concentration range from 0.03 to 1174 μg/g. Intriguingly, the content of citric acid, malonic acid, α-ketoglutaric acid and cis-aconite acid in new rice was each found to be distinctively higher than that in old rice by several times. Even mixtures of old and new rice were found to show much difference in the concentration of citric acid and malic acid.

CONCLUSION

A green analytical method has been developed for the simultaneous determination of CCAs by LC/MS analysis, and the identification of old rice samples from new ones was easily carried out according to their CCA content for the first time. The results indicated that the described method has powerful potential for the accurate identification of old rice samples from new ones.

An Eco-Friendly RP-HPLC Method Development and Validation for Quantification of Favipiravir in Bulk and Tablet Dosage Form Followed by Forced Degradation Study

In this work, an eco-friendly simple, precise reverse phase high-performance liquid chromatography (HPLC) method has been developed and validated for Favipiravir in bulk and tablet dosage form followed by its force degradation study. The proposed method was validated to obtain official requirements including stability, accuracy, precision, linearity, robustness and selectivity as per International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) Guidelines. The estimation was developed on C (18) column reversed-phase using the mobile phase composition as methanol:water (10:90 v/v). The flow rate was set as 1 ml/min, and the maximum absorption was observed at 323 nm using Shimadzu Photo Diode Array detector. The Favipiravir, drug showed a precise and good linearity at the concentration ranges of 10-50 μg/mL. The Revearse Phase High Perforance Liquid Chromatography assay showed the highest purity ranging from 99.90 to 100.02% for Favipiravir, tablet dosage form, and 100.15% was the mean percentage purity. The percent recovery was found within the acceptance limit of (98.6-100.0%). Intra- and inter-day precision studies of the method were less than the maximum allowable limit percentage of relative standard deviation ≤ 2.0. The Favipiravir retention time was found to be 5.00 min. To examine the stability of the drug, various forced degradation studies were conducted on Favipiravir Active Pharmaceutical Ingredient. The developed method was validated according to the ICH guidelines. A very quick, cost-effective, precise and accurate HPLC method for the determination of Favipiravir has been developed and validated in compliance with ICH guidance Q2.

A non-extraction sequential injection method for determination of loratadine using formation of its ion-association complex with bromocresol purple in acetonitrile

The formation of an ion-association complex (IA) between sulfonephthalein dye and basic nitrogen-containing compound in an organic solvent medium has been for the first time used to develop an automated SIA method. In highly polar aprotic solvents, the tautomeric equilibrium for such dyes is strongly shifted towards the colorless lactonic form. The addition of a basic nitrogen-containing substance leads to the formation of IA with a highly colored quinonoid form, which is accompanied by an increase in the absorbance of the dye band at approximately 400 nm. Protonation of pyridine nitrogen in loratadine, structure and binding places of IA were shown using quantum-chemical calculations. The very simple, direct and non-extraction spectrophotometric SIA method with high throughput of 43 h-1 was developed based on the formation of IA between loratadine and bromocresol purple in the medium of acetonitrile used both as solvent and carrier. The calibration graph was linear in the concentration range from 1.0 to 20 mg L-1 with correlation coefficient of 0.9992. The developed method was successfully applied to the analysis of pharmaceutical formulations.

Eco-Friendly Simultaneous Estimation of Ponceau 4R and Carmoisine Employing an Analytical Quality by Design-Aided RP-HPLC Method in Commercial Food Samples Utilizing a Green Ultrasound-Assisted Extraction Technique

BACKGROUND

Ponceau 4R (E124) and carmoisine (CMS; E122) are frequently utilized azo synthetic dyes in the food industry owing to their aesthetically pleasing coloration and broad consumer acceptability. It is imperative to prioritize environmentally favorable technologies for quantifying these dyes, as excessive consumption of these poses significant health risks.

OBJECTIVE

The primary objective of this research was to establish a reversed-phase (RP)-HPLC method that could simultaneously detect Ponceau 4R and CMS, implementing green analytical chemistry (GAC) and analytical quality by design (AQbD), using an ultrasound-assisted extraction (UAE) technique in commercial food samples.

METHODS

An Agilent Eclipse Plus column (C18, 250 × 4.6 mm id, 5 µm) was utilized for effective separation with a mobile phase of ethanol-acetate buffer pH 5 (60:40, v/v), flow rate of 1 mL/min, and detection wavelength of 515 nm. Critical variables selected for method optimization were ethanol percentage and flow rate, determined using central composite design (CCD). In order to adhere to the 12 principles of green chemistry, hazardous solvents were substituted with ethanol, which is distinguished by its ease of use, effectiveness, and ecological sustainability. The greenness assessment was conducted utilizing the green analytical procedure index (GAPI), analytical eco-scale (AES), and analytical greenness metrics (AGREE).

RESULTS

The respective retention times for Ponceau 4R and CMS were 2.276 and 3.450 min. The recovery rate of Ponceau 4R and CMS fluctuated between 70% and 102% and 80% and 102%, respectively, across various marketed food samples. The procedure passed validation in accordance with the International Conference on Harmonization Q14 guidelines.

CONCLUSION

The devised method demonstrates that the validation parameters like linearity, precision, sensitivity, and reproducibility are within the specified limits of ICH guidelines. The greenness assesment tools GAPI, AES, and AGREE produced the most favorable results.

HIGHLIGHTS

In future, environmentally sustainable, solvent-based, robust AQbD methodologies for assessing varieties of food colorants may be adopted and improved commercially.

Development of Eco-Friendly Scattering and Fluorimetric Methods for the Determination of Clemastine Through Its Interaction with Eosin Y: Assessment of Whiteness, Blueness, and Greenness Tools

For the first time, clemastine was estimated in this work utilizing two validated resonance Rayleigh scattering (RRS) and fluorimetric methods. The methods relied on forming an association complex in an acidic medium between eosin Y reagent and clemastine. In the spectrofluorimetric approach, the investigated drug was quantified by quenching the fluorescence-emission intensity of eosin Y at 543.5 nm. The RRS method relied on enhancing the RRS spectrum at 331.8 nm, which is produced when eosin Y interacts with clemastine. Suitable conditions were established for the reaction to achieve maximum sensitivity. The linear values obtained from the spectrofluorimetric approach and the RRS method fall into the ranges of 0.2-1.5 µg mL- 1 and 0.25-2.0 µg mL- 1, respectively. It was established that the detection limits for these methods were 0.045 µg mL- 1 and 0.059 µg mL- 1, respectively. The developed methodologies yielded acceptable recoveries when used to estimate the quantity of clemastine in its pharmaceutical tablet dosage form. Regarding the use of greener solvents that were chosen, the suggested and reported methods were compared with the help of the Green Solvents Selecting (GSST) tool for assessing hazardous solvents to achieve sustainability. Furthermore, analytical Eco scale and comprehensive assessments of whiteness, blueness, and greenness were carried out utilizing Modified NEMI, ComplexGAPI, and AGREE evaluation tools. Additionally, recently developed tools such as BAGI and RGB 12 were applied to assess the blueness and the whiteness of the suggested methods.

A Green HPLC Approach to Florfenicol Analysis in Pig Urine

Florfenicol (FF) is a broad-spectrum antibiotic used to treat gastrointestinal and respiratory infections in domestic animals. Considering FF's rapid elimination via urine after drug treatment, its use increases concerns about environmental contamination. The objective of the study was to establish a sustainable chromatographic method for simple analysis of FF in pig urine to investigate the urinary excretion of FF after a single intramuscular administration of 20 mg FF/kg body weight. The urine sample was prepared using a centrifuge and regenerated cellulose filter, and the diluted sample was analyzed. The method was validated in terms of linearity, the limit of detection (0.005 µg/mL) and quantitation (0.016 µg/mL), repeatability and matrix effect (%RSD ranged up to 2.5), accuracy (varied between 98% and 102%), and stability. The concentration-time profile of pig urine samples collected within 48 h post-drug administration showed that 63% of FF's dose was excreted. The developed method and previously published methods used to qualify FF in the urine of animal origin were evaluated by the National Environmental Method Index (NEMI), Green Analytical Procedure Index (GAPI) and Analytical GREENness Metric Approach (AGREE). The greenness profiles of published methods revealed problems with high solvents and energy consumption, while the established method was shown to be more environmentally friendly.

Microwave-assisted UV digestion of starch and skimmed milk powder: Environmentally friendly protocol for essential and toxic elements determination

The present work evaluated a microwave-assisted wet digestion method using diluted HNO3 with in situ UV radiation for the digestion of starch and skimmed milk powder for further metals determination by spectrometric plasma-based techniques. The sample digestion was conducted using an in situ UV lamp (electrodeless discharge lamp), and the digestion efficiency was improved by employing O2 (20 bar) and 2 mL 30 % H2O2 as auxiliary reagents. The accuracy of the proposed digestion method was evaluated by metals determination (Ca, Cd, Cu, Fe, K, Mg, Mo, Mn, Na, Pb, and Zn) in certificated reference material, which agreed with certified values (Student t-test <0,05). With the use of a UV lamp an environmentally friendly protocol was developed for starch and skimmed milk powder digestion using 0.1 mol L-1 HNO3 with auxiliary reagents (H2O2 or O2). The RCC value ranged from 0.9 to 1.2 % (starch and skimmed milk powder, respectively). The simultaneous cooling approach further improved the digestion efficiency (RCC <0,3 % for both samples), allowing to use milder digestion conditions, or even just water, being environmentally friendly, reducing the waste generation and reagents consumption, allowing food quality control through a greener approach.

Towards green extraction of bioactive natural compounds

The increasing interest in natural bioactive compounds is pushing the development of new extraction processes that may allow their recovery from a variety of different natural matrices and biomasses. These processes are clearly sought to be more environmentally friendly than the conventional alternatives that have traditionally been used and are closely related to the 6 principles of green extraction of natural products. In this trend article, the most critical aspects regarding the current state of this topic are described, showing the different lines followed to make extraction processes greener, illustrated by relevant examples. These include the implementation of new extraction technologies, the research on new bio-based solvents, and the development of new sequential process and biorefinery approaches to produce a full valorization of the natural sources. Moreover, the future outlook in the field is presented, in which the main areas of evolution are identified and discussed.

Removal of arsenic(V) using pure zeolite (PZ) and activated dithizone zeolite (ADZ) from aqueous liquids: application to green analytical chemistry

The primary aim of the present investigation was to evaluate the efficiency of pure zeolite and activated dithizone zeolite for arsenic(V) removal from aqueous solutions. The analytical eco-scale and analytical greenness for sample preparation results confirm that the proposed method is environmentally friendly. Zeolite adsorbents were characterized and tested for their ability to adsorb arsenic(V) from wastewater. Our study delved into arsenic(V) sorption behavior on pristine and activated zeolites. Through steady-state experiments using pure zeolite and activated dithizone zeolite, we examined the sorption of arsenic from aqueous solutions. We optimized operational parameters, including pH, adsorbent dosage, contact time, and arsenic(V) concentration. Our findings revealed that the Langmuir and Freundlich adsorption isothermal models were highly influential in fitting the experimental data, resulting in statistically significant outcomes. This study highlights the potential of zeolites as outstanding adsorbents for removing arsenic(V) from aqueous solutions. The calculated maximum adsorption capacity (qmax) of pure zeolite and activated dithizone zeolite was 18.2 and 21.1(mg/g), respectively, with R2 = 0.999. According to Freundlich's linear model, the experimental isothermal data indicated that activated dithizone zeolite has a higher value of kf constant and a lower value of the 1/n constant than that obtained for pure zeolite. These results imply favorable adsorption of arsenic(V) on activated dithizone zeolite.

A new green fluorimetric micelle complexation approach for reduction of the consumed solvent and quantification of avapritinib in biological fluids

Avapritinib (AVA) is the first medication authorized by the US-FDA in 2020 for the management of gastrointestinal stromal tumours (GISTs) that can't be treated by surgery. Cancer is among the most common causes of death worldwide and is the second most common cause of death after cardiovascular disease. Therefore, a quick, easy, sensitive, and straightforward fluorimetric approach was used to analyse AVA in pharmaceutical materials and blood plasma (pharmacokinetic). The suggested technique relies on 2% sodium dodecyl sulphate (SDS, pH 4) micellar system augmentation of the fluorescence of the tested drug. The technique demonstrated high relative fluorescence intensity (RFI) at 430 nm after excitation at 340 nm. Concentrations ranging from 20.0-400.0 ng mL-1 with a limit of quantitation of 9.47 ng mL-1 were used to obtain luminescence data for the studied medicine. In addition, the quantum yield of the AVA fluorescence was increased with the gradual addition of a surfactant at a concentration above its critical micellar level. This knowledge has been exploited to enhance the effectiveness of a spectrofluorometric technique for the estimation of AVA in human plasma (98.95 ± 1.22%) and uniformity tests with greenness assessments. The conditions for enhanced fluorescence were optimized and fully validated using US-FDA and International Conference on Harmonization (ICH) rules. This innovative strategy was expanded for AVA stability research in human plasma across various circumstances. This approach is an eco-friendly solution compared to traditional testing methods that use hazardous chemicals.

A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method for determination of phytohormones in the medicinal plant saffron

Saffron (Crocus sativus L.) is a valuable Chinese herb with high medicinal value. Saffron pistils are used as medicine, so increasing the number of flowers can increase the yield. Plant hormones have essential roles in the growth and development of saffron, as well as the response to biotic and abiotic stresses (especially in floral initiation), which may directly affect the number of flowers. Quantitative analysis of plant hormones provides a basis for more efficient research on their synthesis, transportation, metabolism, and action. However, starch (which interferes with extraction) is present in high levels, and hormone levels are extremely low, in saffron corms, thereby hampering accurate determination of plant-hormone levels in saffron. Herein, we screened an efficient and convenient pre-treatment method for plant materials containing abundant amounts of starch. Also, we proposed an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantification of abscisic acid (ABA) and auxin (IAA). Then, the method was applied for the detection of hormone-content differences between flowering and non-flowering top buds, as well as between lateral and top buds. Our method showed high sensitivity, reproducibility, and reliability. Specifically, good linearity in the range 2-100 ng ml-1 was achieved in the determination of ABA and IAA, and the correlation coefficient (R2) was >0.9982. The relative standard deviation was 2.956-14.51% (intraday) and 9.57-18.99% (interday), and the recovery range was 89.04-101.1% (n = 9). The matrix effect was 80.38-90.50% (n = 3). The method was thoroughly assessed employing various "green" chemistry evaluation tools: Blue Applicability Grade Index (BAGI), Complementary Green Analytical Procedure Index (Complex GAPI) and Red Green Blue 12 Algorithm (RGB12). These tools revealed the good greenness, analytical performance, applicability, and overall sustainability alignment of our method. Quantitative results showed that, compared with saffron with a flowering phenotype cultivated at 25 °C, the contents of IAA and ABA in the terminal buds of saffron cultivated at 16 °C decreased significantly. When cultivated at 25 °C, the IAA and ABA contents in the terminal buds of saffron were 1.54- and 4.84-times higher than those in the lateral buds, respectively. A simple, rapid, and accurate UPLC-MS/MS method was established to determine IAA and ABA contents. Using this method, a connection between the contents of IAA and ABA and the flowering phenotype was observed in the quantification results. Our data lay a foundation for studying the flowering mechanism of saffron.

A flow-batch lab-in-syringe foam microextraction platform for the simultaneous preconcentration and in situ membraneless gas-liquid separation of mercury prior to cold vapor atomic absorption spectrometry

Herein, the proof-of-concept of a novel lab-in-syringe (LIS) foam microextraction platform is presented as a front-end to cold vapor atomic absorption spectrometry (CVAAS) for the simultaneous preconcentration and membraneless gas-liquid separation (GLS) of inorganic mercury in biological samples. The proposed method is based on the on-line formation of the ammonium pyrrolidine dithiocarbamate complex with mercury that was retained in the pores of polyurethane foam immobilized on the piston of the LIS system. Metal complex elution and in situ mercury vapor generation are accomplished inside the microsyringe in a flow-batch format, while the separation of vapor species is achieved via the membraneless GLS found at the top of the syringe's barrel. Under optimized operation conditions, for 90 s preconcentration time, the limit of detection was 0.02 μg L-1 and the repeatability (RSD) was 3.8% (at the 0.5 μg L-1 concentration level), within a working range extending up to 4.0 μg L-1. The practicality of the novel manifold was demonstrated using the Blue Applicability Grade Index, while the accuracy of the method was evaluated using certified reference materials and spiked samples.

Eco-friendly micellar HPLC approach for simultaneous estimation of combination therapy for hidradenitis suppurativa: Applications to spiked human plasma and different dosage forms

This study introduces a new method for analyzing rifampicin, moxifloxacin, and metronidazole using a green micellar High Performance Liquid Chromatography-Ultraviolet method in bulk drugs, different commercial formulations, and spiked human plasma. The combined therapy of these three broad-spectrum antibiotics is used to cure refractory hidradenitis suppurativa (HS), an inflammatory condition affecting the skin. The sustainable separation was attained on a reversed-phase C18 Kinetex® column maintained at ambient temperature in less than 5 min. The mobile phase comprises 0.1 M sodium dodecyl sulfate (SDS) in water, pH 3.5, adjusted using o-phosphoric acid, and 10% n-butanol. The flow rate was 1 mL/min, with 10 μL injection volume and UV detection at 230 nm. The impact of three key significant variables, SDS concentration, n-butanol percentage, and the mobile phase pH, on suitability parameters was studied. ICH and FDA guidelines were committed to when validating the technique. The results showed linear calibration graphs with high precision and accuracy, in both pure and spiked plasma. The method is efficient, easy to use, and has a high sample throughput, making it suitable for routine analysis in the quality control department and therapeutic monitoring. It is also evaluated as a green-and-white substitute for traditional reported methods.

Fast and low-cost method for direct and simultaneous determination of nitrogen and carbon in soybean leaves using benchtop and portable near-infrared devices

BACKGROUND

The current techniques for determining carbon and nitrogen content to provide information about the nutritional status of plants are time-consuming and expensive. For this reason, the objective of this study was to develop an analytical method for the direct and simultaneous determination of nitrogen and carbon elemental content in soybean leaves using near-infrared spectroscopy and compare the performance of conventional (1100-2500 nm spectral range) and portable equipment (1100-1700 nm spectral range). Partial least-squares regression models were developed using 27 soybean leaf samples collected during the 2021 harvest and applied for the simultaneous determination of carbon and nitrogen in 13 samples collected during the 2022 harvest.

RESULTS

The root-mean-square error of prediction values for nitrogen and carbon were low (2.42 g kg-1 and 4.37 g kg-1 respectively) for the benchtop method yielded low but higher for the portable method (3.82 g kg-1 and 10.7 g kg-1 respectively). The benchtop method did not show significant differences when compared with the reference method for determining nitrogen and carbon. In contrast, the portable methodology showed potential as a screening method for determining nitrogen levels, particularly in fieldwork.

CONCLUSION

The methodologies evaluated in this study were implemented and evaluated under real crop monitoring conditions, using independent sets of calibration and prediction samples. Their utilization enables the acquisition of cost-effective, safe analytical data aligning with the principles of green analytical chemistry. © 2023 Society of Chemical Industry.

Liquid phase microextraction based on natural deep eutectic solvents of psychoactive substances from biological fluids and natural waters

In this paper, natural deep eutectic solvents (NADES)-based for liquid phase microextraction (LPME) is proposed for the isolation of different psychoactive substances in water and biological fluids followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The NADES composition was optimized (L-menthol:octanoic acid, 1:2 M ratio) prior to the study of the extraction conditions such as sample and elution volumes, obtaining up to 16-fold preconcentration factor. Next, the quality parameters were studied including linearity from LOQs (0.0006-0.05 μg L-1) to 100 μg L-1, precision values (expressed as relative standard deviation, RSD≤8 %) and recoveries above 70 % in most cases. Certified saliva and serum samples were analyzed by the proposed method to assess the accuracy of the developed procedure, providing values statistically comparable to the certified ones. In addition, the proposed methodology was evaluated by applying green metrics (AGREEprep tool) and the obtained values were compared with those reported for a similar procedure using LPME with common organic solvents such as chloroform or dichloromethane, outperforming them in both cases, which points out the potential of this method from the sustainability point of view.

Chemometrics-assisted excitation-emission matrix fluorescence spectroscopy for real-time migration monitoring of multiple polycyclic aromatic hydrocarbons from plastic products to food simulants

Polycyclic aromatic hydrocarbons (PAHs), as a class of organic pollutants that have attracted much attention, are likely to be formed with the production and processing of plastic products, and they may migrate from contaminated plastic products to food, causing the risk of poisoning or cancer. In this study, migration tests were carried out on disposable plastic products for food contact, and a novel strategy that combines excitation-emission matrix (EEM) fluorescence spectroscopy with the advanced second-order calibration method based on the three-direction resection alternating trilinear decomposition (TDR-ATLD) algorithm was used to monitor the migration of three PAHs anthracene (ANT), pyrene (PYR), and phenanthrene (PHE) from the plastic products to food simulants in real-time. With the "second-order advantage", even if the fluorescence spectra of the target analytes overlapped seriously, and other unknown substances migrated from the plastic products to food simulants, accurate qualitative and quantitative results were still obtained by the proposed method. In the static system, the coefficient of determination (R2) of the three PAHs within the calibration range were all greater than 0.99, and the average spiked recoveries were 99.5-107.1%, with the standard deviation lower than 8.9%. The figures of merit (FOMs) and intra- or inter-day precision also showed good feasibility and reliability of the method. In the simulation study of the migration kinetic process, three PAHs can be quantified in real-time in complex matrix, then the related migration equations were established. The results indicate that the proposed method can be used for real-time migration quantitative monitoring of PAHs, providing a potential and available method for the study of the migration kinetics of hazardous substances from food contact materials to food or food simulants.

Dual sorbent coating based magnet-integrated fabric phase sorptive extraction as a front-end to gas chromatography-mass spectrometry for multi-class pesticide determination in water samples

Magnet-integrated fabric phase sorptive extraction (MI-FPSE) is a sample preparation technique that has proved to be a powerful tool for environmental analysis. The fabrication and application of magnet-integrated dual sorbent-based FPSE membrane prepared by combining two different sol-gel sorbent-coated disks of different polarities together with a magnetic bar inserted between the two membranes to allow the stirring, was examined as novel preparation technique that not required samples pretreatments. The dual sorbent-based sample preparation platforms (made up of poly(tetrahydrofuran) and Carbowax 20M) were used for the extraction of seven classes of pesticides from ambient surface water samples prior to their determination by gas chromatography-mass spectrometry. Initially, different single and dual sol-gel sorbent-based MI-FPSE membranes were evaluated in terms of their extraction efficiency. The MI-FPSE with dual sol-gel sorbents were found to be superior to the single-materials MI-FPSE devices in terms of extraction recovery. The main parameters affecting the MI-FPSE extraction protocol (e.g., adsorption time, sample volume, stirring rate, salt addition, eluent type, desorption time and elution volume) were investigated. The selected extraction protocol enabled detection limits in the range between 0.001 and 0.16 ng mL-1. Furthermore, good relative standard deviation values for the intra-day and inter-day repeatability studies were obtained and were lower than 5.9 and 9.9 %, respectively. The proposed method was successfully used for the multi-class analysis of environmental surface water samples.

Different spectrophotometric methods for simultaneous quantitation of Vericiguat and its alkaline degradation product: a comparative study with greenness profile assessment

Investigations concerning novel drugs and their induced degradation products are necessary for clinical research and quality control in the pharmaceutical industry. Four spectrophotometric techniques have been performed for simultaneous quantitation of Vericiguat (VER) and its alkali-induced degradation product (ADP) without prior separation. Method A is a dual wavelength method (DW) that estimates the absorbance difference at 314-328 nm, and 246-262 nm for VER and ADP; respectively. Method B uses a ratio difference method (RD) to estimate the ratio spectrum's amplitude difference (DP318-342) and (DP284-292) for VER and ADP; respectively. Method C uses a first derivative ratio method (1DD) to estimate the peak ratio spectrum amplitude of the first derivative at 318 and 275 nm for VER and ADP; respectively. Method D uses the mean centering of the ratio spectra (MCR) to estimate amplitude values for VER and ADP at 337 and 292 nm; respectively. In a concentration range of 5.00-50.00 µg/mL for VER and 5.00-100.00 µg/mL for ADP, the methods were validated following ICH criteria and utilized to estimate VER in bulk and its dosage form. The methods' greenness was assessed via three tools: the green analytical procedure index (GAPI), analytical eco-scale, and analytical greenness assessment (AGREE).

Ternary solvent based homogeneous liquid-liquid microextraction for the preconcentration of organochlorine pesticides from water and apple juice samples

In the present study, the optimal experimental conditions were determined by optimizing the effect of extraction solvent types and volume, salt types and concentration, centrifugation speed and time using one variable at a time. Under optimal experimental conditions, calibration curves were constructed separately using water and apple juice samples as representative matrices, and good linearities were achieved over a wide concentration range of 0.2-1600 ng L-1 with a coefficient of determination (r2) ≥ 0.998. The limits of detection (LOD) and limits of quantification (LOQ), determined to be 3 and 10 times the signal-to-noise ratios (S/N), were between 0.07-3.9 and 0.2-12.0 ng L-1 for water samples and 2.6-10.0 and 8.0-30.0 ng L-1 for the apple juice sample respectively. The precisions study showed %RSD values of ≤6% for both matrices, indicating satisfactory precisions. The enrichment factors and recoveries of the proposed method ranged from 41.4-74.5 and 86-109% respectively. The proposed method could be used as a simple and environmentally friendly alternative for the analysis of OCPs from environmental and food matrices. This method potentially offers a more sustainable and effective approach to monitoring OCPs in environmental and food products. Its use in the analysis of apple juice samples is particularly novel and can provide valuable insights into pesticide contamination in fruit juices.

Development and Validation of Green Chromatographic Approaches for Simultaneous Determination of Aspirin, Rosuvastatin and Clopidogrel in their Tertiary Mixture

Reduction of environmental pollution sources is the main target of green chemistry; it is applied across the life cycle of a chemical product. Scientists try to switch to eco-friendly practices to diminish the negative impact of chemicals and solvents on the environment. Analytical chemistry is one of the main fields that mounted green chemistry approach. In this work, sensitive and selective green chromatographic methods with UV detection are described for the simultaneous determination of aspirin, rosuvastatin and clopidogrel. The first proposed method is an RP-HPLC one, which was described and successfully validated for the simultaneous separation and determination of the three components on Prontosil Hyperchom C18 (250 × 4.6 mm, 5 μm) column using an isocratic elution. The second method was a TLC spectrodensitometry in which the three components were separated, identified and quantified. The drugs were applied on silica gel plates, and developed using n-heptane: acetone: glacial acetic acid (60:40:0.4, by volume). The three drugs resolved bands were quantified by spectrodensitometric scanning at 240 nm. Both methods were validated according to ICH, statistically compared to the official methods with full greenness investigation to confirm that the proposed methods are viable alternatives for quality assessment of this combination.

Sustainable plant-wearable sensors for on-site, rapid decentralized detection of pesticides toward precision agriculture and food safety

The synergy between eco-friendly biopolymeric films and printed devices leads to the production of plant-wearable sensors for decentralized analysis of pesticides in precision agriculture and food safety. Herein, a simple method for fabrication of flexible, and sustainable sensors printed on cellulose acetate (CA) substrates has been demonstrated to detect carbendazim and paraquat in agricultural, water and food samples. The biodegradable CA substrates were made by casting method while the full electrochemical system of three electrodes was deposited by screen-printing technique (SPE) to produce plant-wearable sensors. Analytical performance was assessed by differential pulse (DPV) and square wave voltammetry (SWV) in a linear concentration range between 0.1 and 1.0 μM with detection limits of 54.9 and 19.8 nM for carbendazim and paraquat, respectively. The flexible and sustainable non-enzymatic plant-wearable sensor can detect carbendazim and paraquat on lettuce and tomato skins, and also water samples with no interference from other pesticides. The plant-wearable sensors had reproducible response being robust and stable against multiple flexions. Due to high sensitivity and selectivity, easy operation and rapid agrochemical detection, the plant-wearable sensors can be used to detect biomarkers in human biofluids and be used in on-site analysis of other hazardous chemical substances.

Low-Cost Pocket Fluorometer and Chemometric Tools for Green and Rapid Screening of Deoxynivalenol in Durum Wheat Bran

Cereal crops are frequently contaminated by deoxynivalenol (DON), a harmful type of mycotoxin produced by several Fusarium species fungi. The early detection of mycotoxin contamination is crucial for ensuring safety and quality of food and feed products, for preventing health risks and for avoiding economic losses because of product rejection or costly mycotoxin removal. A LED-based pocket-size fluorometer is presented that allows a rapid and low-cost screening of DON-contaminated durum wheat bran samples, without using chemicals or product handling. Forty-two samples with DON contamination in the 40-1650 µg/kg range were considered. A chemometric processing of spectroscopic data allowed distinguishing of samples based on their DON content using a cut-off level set at 400 µg/kg DON. Although much lower than the EU limit of 750 µg/kg for wheat bran, this cut-off limit was considered useful whether accepting the sample as safe or implying further inspection by means of more accurate but also more expensive standard analytical techniques. Chemometric data processing using Principal Component Analysis and Quadratic Discriminant Analysis demonstrated a classification rate of 79% in cross-validation. To the best of our knowledge, this is the first time that a pocket-size fluorometer was used for DON screening of wheat bran.

A mini review of hazardous wastes generated by environmental analytical laboratories: a perspective from Sri Lanka as an economically developing country

Attention given to environmental pollution caused by environmental analytical (EA) laboratories is very poor in Sri Lanka (an economically developing country). This article discusses EA laboratory effluents and hazardous solid wastes, current environmental management practices, and the legislative requirements in Sri Lanka. Effluent quantities generated are low (29.99-63.09 L/week), but characterized with variable pH, high chemical oxygen demand (COD), total suspended solids (TSS) and heavy metals, and very high ecotoxicity. Quantities of chemical-contaminated solid wastes is 80-100 kg/year (excluding outdated and rejected chemicals). Most laboratories dispose chemical-contaminated solid wastes mixed with non-hazardous recyclables using the services of local authorities and some laboratories (particularly in areas where there is no municipal solid waste collection), practice backyard dumping or open burning, while a few laboratories employ private parties to dispose or burn these wastes elsewhere. Only one laboratory is disposing chemical-contaminated solid wastes through co-processing. Appropriate waste management strategies (including some cleaner production concepts) are discussed in this paper for selected streams of hazardous wastes.

AGREE and ESA for Greenness Assessment of a Novel Validated RP-HPLC Method for Simultaneous Determination of Aspirin, Warfarin and Clopidogrel in Rat Plasma: Application to Pharmacokinetic Study of the Possible Interaction between the Three Drugs

The green profile of the developed method is assessed and compared with previously reported methods. Percutaneous coronary intervention is a procedure where a catheter is utilized to place a stent in order to facilitate opening of the blood vessels in the heart. Triple antithrombotic therapy includes oral anticoagulation as warfarin and dual antiplatelet therapy (composed of aspirin and clopidogrel bisulfate). The aim of the current study was to evaluate the pharmacokinetic parameters of ASP, WAR and CLP and to investigate the possible interaction between the three drugs upon co-administration in rats. A selective and precise RP-HPLC method was developed for the simultaneous determination of ASP, WAR and CLP in rat plasma. Pharmacokinetic study was conducted in rats that received ASP, WAR and CLP as an application of the developed method. From the statistical evaluation of the pharmacokinetic parameters, it was observed that the co-administration of ASP, WAR and CLP significantly increased the ASP and CLP bioavailability in rats. A significant drug-drug interaction was confirmed in the current study. The elevated Cmax of ASP and CLP upon the co-administration of ASP, WAR and CLP may explain the reported bleeding.

From capillaries to microchips, green electrophoretic features for enantiomeric separations: A decade review (2013-2022)

Enantioseparation by the electromigration-based method is well-established and widely discussed in the literature. Electrophoretic strategies have been used to baseline resolve complex enantiomeric mixtures, typically using a selector substance into the background electrolyte (BGE) from capillaries to microchips. Along with developing new materials/substances for enantioseparations, it is the concern about the green analytical chemistry (GAC) principles for method development and application. This review article brings a last decade's update on the publications involving enantioseparation by electrophoresis for capillary and microchip systems. It also brings a critical discussion on GAC principles and new green metrics in the context of developing an enantioseparation method. Chemical and green features of native and modified cyclodextrins are discussed. Still, given the employment of greener substances, ionic liquids and deep-eutectic solvents are highlighted, and some new selectors are proposed. For all the mentioned selectors, green features about their production, application, and disposal are considered. Sample preparation and BGE composition in GAC perspective, as well as greener derivatization possibilities, were also addressed. Therefore, one of the goals of this review is to aid the electrophoretic researchers to look where they have not.

Liquid chromatographic methods for the analysis of canagliflozin: concise overview and greener assessment

There is a pressing need for the development of greener liquid chromatographic bioanalytical methods for antidiabetic drugs for plasma monitoring and revisiting patients' dosage regimens. Besides, analytical methods are also needed for the quality assurance of finished drug products and regulatory approval. Therefore, the present review focuses on the reported liquid chromatographic methods (LC and LC-MS/MS) that are applied for quality control, forced degradation, and pharmacokinetic studies of a newer antidiabetic agent, canagliflozin (CNG). These reported studies are summarized based on liquid chromatographic separation parameters, such as column dimensions, mobile-phase compositions, flow rate, and use of different detection systems (UV, PDA, and mass spectrometry). The sample pretreatment of biological fluids, which is important for minimizing the matrix effect, is dealt with separately. Liquid-liquid extraction was found to be the most preferred methodology adopted for sample pretreatment followed by the solid-phase extraction technique. However, miniaturized novel pretreatment methods are untraceable in the literature for the extraction of CNG. Special emphasis is paid to the assessment of the greenness profiles of the reported analytical methods for the consideration of sustainable development and green analytical chemistry. Based on the National Environmental Method Index (NEMI) assessment tool, most of the reported studies fulfilled around half of the parameters and were found to be about 50% greener. It is proposed that toxic or hazardous solvents, such as acetonitrile or methanol, should be replaced with greener and environmentally friendly solvents. Thus, there is a need to develop more robust, efficient, and greener liquid chromatographic methods for the determination of CNG in biological fluids and drug products.

Condition optimization of eco-friendly RP-HPLC and MCR methods via Box-Behnken design and six sigma approach for detecting antibiotic residues

A precise, Eco-friendly, and highly sensitive RP-HPLC method was employed using quality-by-design principles to concurrently identify cephalexin and cefixime residues in the manufacturing machines using a hypersil BDS C18 column (250 × 4.6 mm, 5 μm) at wavelength 254 nm. The Box-Behnken design was applied to obtain the best chromatographic conditions with the fewest possible trials. Three independent factors viz organic composition, flow rate, and pH were used to assess their effects on the responses' resolution and retention time. Overlay plot and desirability functions were implemented to predict responses of the high resolution and relatively short retention time using a mobile phase composed of acidic water: acetonitrile (85:15, v/v) at pH 4.5 adjusted by phosphoric acid with a flow rate of 2.0 mL/min. The spectral overlapping of the drugs was successfully resolved by the mean centering ratio (MCR) spectra approach at 261 nm and 298 nm for cephalexin and cefixime, respectively. Good linearity results were obtained for the suggested HPLC and MCR methods over the concentration range of (0.05-10 ppm) and (5-30 ppm) with a detection limit of 0.003, 0.004, 0.26, and 0.23 ppm, and quantitation limits of 0.008, 0.013, 0.79, and 0.68 ppm for cephalexin and cefixime, respectively, with a correlation coefficient of ≥ 0.9998 and good swab recovery results of 99-99.5%. A process capability index was accomplished for chemical and micro results, illustrating that both are extremely capable. The suggested method was effectively validated using ICH recommendations.

Validated and selective potentiometric analysis of anti-coagulant edoxaban via a screen-printed electrode: green assessment by Eco-Scale and Complex-GAPI

Thromboembolism because of coronavirus infection (COVID-19) resulted in increasing the number of sudden deaths after recovery. So, patients were switched to edoxaban tosylate monohydrate (EDTM) therapy after low molecular weight heparin to shorten the hospitalization period. In response to increase the demand for EDTM, we developed a home-made screen-printed electrode to determine EDTM in its pure form and pharmaceutical dosage form. Optimized conditions were achieved with a screen-printed electrode utilizing EDTM-Phosphotungstic acid (EDTM-PTA) as an ion pair complex and a plasticizer dibutyl phthalate with a Nernstian slope of 58.78 ± 0.1 mV decade−1 at the concentrations ranging from 5.0 × 10–6 to 1.0 × 10–2 M EDTM (R2 = 0.9985). The detection limit was 4.3 × 10–6 M. Our method was proven to be eco-friendly after assessment by Eco-Scale and Complex-GAPI. The results obtained were validated according to ICH guidelines and were found to agree with those gained from the reference method.

Improving greenness and sustainability of standard analytical methods by microextraction techniques: A critical review

Since environmental awareness has increased in analytical chemistry, the demand for green sample preparation methods continues to grow. Microextractions such as solid-phase microextraction (SPME) and liquid-phase microextraction (LPME) miniaturize the pre-concentration step and are a more sustainable alternative to conventional large-scale extractions. However, the integration of microextractions in standard and routine analysis methods is rare, although these applications are used most frequently and have a role model function. Therefore, it is important to highlight that microextractions are capable to replace large-scale extractions in standard and routine methods. This review discusses the greenness, benefits, and drawbacks of the most common LPME and SPME variants compatible with gas chromatography based on the following key evaluation principles: Automation, solvent consumption, hazards, reusability, energy consumption, time efficiency, and handling. Furthermore, the need to integrate microextractions into standard and routine analytical methods is presented by using method greenness evaluation metrics AGREE, AGREEprep, and GAPI applied to USEPA methods and their replacements.

An integrated automatic lab-in-syringe sol-gel coated foam microextraction platform as a front-end to high performance liquid chromatography for the migration studies of bisphenol A

The proof-of-concept of an integrated automatic foam microextraction lab-in-syringe (FME-LIS) platform coupled to high performance liquid chromatography is presented. Three different sol-gel coated foams were synthesized, characterized, and conveniently packed inside the glass barrel of the LIS syringe pump, as an alternative approach for sample preparation, preconcentration and separation. The proposed system efficiently combines the inherent benefits of lab-in-syringe technique, the good features of sol-gel sorbents, the versatile nature of foams/sponges, as well as the advantages of automatic systems. Bisphenol A (BPA) was used as model analyte, due to the increasing concern for the migration of this compound from household containers. The main parameters that affect the extraction performance of the system were optimized and the proposed method was validated. The limit of detection for BPA were 0.5 and 2.9 μg L^-1, for a sample volume of 50 mL and 10 mL, respectively. The intra-day precision was <4.7% and the inter-day precision was <5.1% in all cases. The performance of the proposed methodology was evaluated for the migration studies of BPA using different food simulants, as well as for the analysis of drinking water. Good method applicability was observed based on the relative recovery studies (93-103%).

A green compliant hand-held selective electrode device for monitoring active pharmaceuticals and the kinetics of their degradation

An in-line smartphone connected to a screen-printed selective electrode hand-held device was used to determine the concentration of distigmine bromide (DB) in its pure and dosage forms as well as its degradation kinetics by continuously measuring the change in the produced emf over time. The main objective, supported by the data presented, is to produce a highly reliable smartphone integrated selective sensor as a portable analyzer with potential high cloud connectivity combining a wide linear dynamic range, the fastest response time with the lowest limits of detection and quantitation while best integrating green analytical chemistry principles. The choice of ionophore used in this approach was guided by computation and the data obtained was compared with traditional analytical techniques. DB, for which there are no previously reported stability-indicating methods and for which four novel such methods are proposed here, was selected as a model drug for this work. At-line UV-spectrophotometry DB assay was obtained by measuring the difference between the spectra of the degradation product and the same concentration of intact drug. The degradation kinetics were studied by this method through tracking the decrease of DB absorbance and/or the increase of a generated degradation product signal over time. Off-line separation based HPLC and TLC stability-indicating methods for DB were also presented. All methods employed in this work were validated for accuracy, precision, specificity, repeatability, linearity, range, detection and quantification limits according to the ICH guidelines and were applied to the analysis of laboratory prepared mixtures as well as commercial products. While all methods proposed were shown to be highly reliable, the smartphone integrated selective sensor is highlighted as a portable analyzer with potential high cloud connectivity and was shown to combine a wide linear dynamic range, the fastest response time with the lowest limits of detection and quantitation while best integrating green analytical chemistry principles.

Column selection considerations in compact capillary liquid chromatography

Recent years have seen significant advances in compact, portable capillary LC instrumentation. This study explores the performances of several commercially available columns within the pressure and flow limits of both the columns and one of these compact LC instruments. The commercially available compact capillary LC system with UV-absorbance detector used in this study is typically operated using columns in the 0.15-0.3 mm internal diameter (i.d.) range. Efficiency measurements (i.e., theoretical plates, N) for six columns with i.d.s in this range and of varying lengths and pressure limits, packed with stationary phases of different particle diameters and morphologies, were made using a mixture of standard alkylphenones. Kinetic plot comparisons between columns that vary by one (or more) of these parameters are described, along with calculated kinetic performance and Knox-Saleem limits. These theoretical performance descriptions provide insight into optimal operating conditions when using capillary LC systems. Based on kinetic plot evaluation of available capillary columns in the 0.2-0.3 mm i.d. range with a conservative upper pressure limit of 330 bar packed with superficially porous particles, a 25 cm column could generate ∼47,000 plates in 7.85 min when operated at 2.4 µL/min. For comparison, more robust 0.3 mm i.d. columns (packed with fully porous particles) that can be operated at higher pressures than can be provided by the pumping system (conservative pump upper pressure limit of 570 bar), a ∼20 cm column could generate nearly 40,000 plates in 5.9 min if operated at 6 µL/min. Across all capillary LC columns measured, higher pressure limits and shorter columns can provide the best throughput when considering both speed and efficiency.

Synthesis of green emitted carbon dots from Vachellia nilotica and utilizing its extract as a red emitted fluorescence reagent: Applying for visual and spectroscopic detection of iron (III)

Principles of Green Analytical Chemistry recommended preferring using reagents from renewable sources and eliminating toxic reagents. Vachellia nilotica is a widespread plant throughout different parts of the world. In this study, using microwave energy, fluorescent carbon dots were synthesized for the first time from Vachellia nilotica pods. The morphology of the prepared carbon dots was characterized by SEM and TEM techniques, and the spectroscopic character exhibit green emission at 480 nm at λ_ex = 386.5 nm. This fluorescence can be effectively quenched by adding Fe (III) ions (Method I). Furthermore, Vachellia nilotica pods were extracted by different solvents, including methanol, deionized water, absolute ethanol, acetone, acetonitrile, and DMF. The acetonitrile extract of Vachellia nilotica exhibited a strong red fluorescence emission at 673.9 at λ_ex = 410 nm. Among various types of salt metals, only Fe (III) can effectively quench the fluorescence intensity of the acetonitrile extract (method II). Moreover, the bright yellow color of the aqueous extract can be changed into violet color. The absorbance of the resulted color can be spectrophotometrically measured at λ _max = 530 nm (method III). The best analytical factors were optimized for the developed methods. The developed methods were applied to determine Fe (III) in different water samples.

New Prospects in the Electroanalysis of Heavy Metal Ions (Cd, Pb, Zn, Cu): Development and Application of Novel Electrode Surfaces

The detection of toxic heavy metal ions, especially cadmium (Cd), lead (Pb), zinc (Zn), and copper (Cu), is a global problem due to ongoing pollution incidents and continuous anthropogenic and industrial activities. Therefore, it is important to develop effective detection techniques to determine the levels of pollution from heavy metal ions in various media. Electrochemical techniques, more specifically voltammetry, due to its properties, is a promising method for the simultaneous detection of heavy metal ions. This review examines the current trends related to electrode formation and analysis techniques used. In addition, there is a reference to advanced detection methods based on the nanoparticles that have been developed so far, as well as formation with bismuth and the emerging technique of screen-printed electrodes. Finally, the advantages of using these methods are highlighted, while a discussion is presented on the benefits arising from nanotechnology, as it gives researchers new ideas for integrating these technologies into devices that can be used anywhere at any time. Reference is also made to the speciation of metals and how it affects their toxicity, as it is an important subject of research.

Smartphone digital image colorimetry combined with dispersive solid-phase microextraction for the determination of boron in food samples

Simple, inexpensive and accurate analytical methods are in high demand. Dispersive solid-phase microextraction (DSPME) was used in combination with smartphone digital image colorimetry (SDIC) to determine boron in nuts as an approach replacing existing costly alternatives. A colorimetric box was designed to capture images of standards and sample solutions. ImageJ software was used to link pixel intensity to the analyte concentration. Under optimum extraction and detection conditions, linear calibration graphs were obtained with coefficients of determination (R²) above 0.9955. Percentage relative standard deviations (%RSD) were below 6.8 %. The limits of detection (LOD) ranged between 0.07 and 0.11 μg mL^-1 (1.8 to 2.8 μg g^-1), which were sufficient for detection of boron in nut samples (i.e., almond, ivory, peanut and walnut), with percentage relative recoveries (%RR) between 92.0 and 106.0 %.

Evaluation of Environmentally Relevant Nitrated and Oxygenated Polycyclic Aromatic Hydrocarbons in Honey

In this work, a novel analytical methodology for the extraction and determination of polycyclic aromatic hydrocarbon derivatives, nitrated (NPAH) and oxygenated (OPAH), in bee honey samples was developed. The extraction approach resulted in being straightforward, sustainable, and low-cost. It was based on a salting-out assisted liquid-liquid extraction followed by liquid chromatography-tandem mass spectrometry determination (SALLE-UHPLC-(+)APCI-MS/MS). The following figures of merit were obtained, linearity between 0.8 and 500 ng g^-1 for NPAH and between 0.1 and 750 ng g^-1 for OPAH compounds, coefficients of determination (r2) from 0.97 to 0.99. Limits of detection (LOD) were from 0.26 to 7.42 ng g^-1 for NPAH compounds and from 0.04 to 9.77 ng g^-1 for OPAH compounds. Recoveries ranged from 90.6% to 100.1%, and relative standard deviations (RSD) were lower than 8.9%. The green assessment of the method was calculated. Thus, the Green Certificate allowed a classification of 87 points. This methodology was reliable and suitable for application in honey samples. The results demonstrated that the levels of nitro- and oxy-PAHs were higher than those reported for unsubstituted PAHs. In this sense, the production chain sometimes transforms foods as direct carriers of contaminants to consumers, representing a concern and demonstrating the need for routine control.

3D printed solid phase microextraction scaffolds as novel tool for sample preparation; application in antifungal drugs analysis

3D printed solid phase microextraction scaffolds as a novel sorbent were introduced for the extraction of antifungal drugs in wastewater and human plasma prior to their determination by HPLC-UV. The designed adsorbent was prepared as cubic scaffolds using fused deposition modeling (FDM) 3D printer and Polylactic acid (PLA) filament. Scaffold surface was chemically modified using alkaline ammonia solution (Alkali treatment). The application of this new design in the extraction of three antifungal drugs ketoconazole, clotrimazole and miconazole was investigated. Alkali surface modification time was optimized (0.5-5hr) and 4hr selected as the best-modification time. Morphology of the modified surface and its chemical changes were studied using Field Emission Scanning Electron Microscope (FE-SEM) and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), respectively. Surface wettability of scaffolds was measured by Water Contact Angel (WCA) and the porosity created in the scaffolds was studied by N₂ adsorption/desorption studies analysis. Analytical performance of the method, under optimum conditions (extraction time: 25 min, desorption solvent: methanol, volume of desorption solvent: 2 mL, desorption time: 10 min, solution pH: 8, solution temperature: 40 °C, salt concentration: 3 mol L^-1) were obtained as 3.10 and 10.0 µg L^-1 for LOD and LOQ, respectively. The calibration graphs were linear in the range of 10-150 µg L^-1 and 10-100 µg L^-1 for wastewater and plasma, respectively.

Development of Green and High Throughput Microplate Reader-Assisted Universal Microwell Spectrophotometric Assay for Direct Determination of Tyrosine Kinase Inhibitors in Their Pharmaceutical Formulations Irrespective the Diversity of Their Chemical Structures

This study discusses the development and validation of a universal microwell spectrophotometric assay for TKIs, regardless of the diversity in their chemical structures. The assay depends on directly measuring the native ultraviolet light (UV) absorption of TKIs. The assay was carried out using UV-transparent 96-microwell plates and the absorbance signals were measured by a microplate reader at 230 nm, at which all TKIs had light absorption. Beer's law correlating the absorbances of TKIs with their corresponding concentrations was obeyed in the range of 2-160 µg mL^-1 with excellent correlation coefficients (0.9991-0.9997). The limits of detection and limits quantitation were in the ranges of 0.56-5.21 and 1.69-15.78 µg mL^-1, respectively. The proposed assay showed high precision as the values of the relative standard deviations for the intra- and inter-assay precisions did not exceed 2.03 and 2.14%, respectively. The accuracy of the assay was proven as the recovery values were in the range of 97.8-102.9% (±0.8-2.4%). The proposed assay was successfully applied to the quantitation of all TKIs in their pharmaceutical formulations (tablets) with reliable results in terms of high accuracy and precision. The assay greenness was evaluated, and the results proved that the assay fulfils the requirements of green analytical approach. The proposed assay is the first assay that can analyse all TKIs on a single assay system without chemical derivatization or modifications in the detection wavelength. In addition, the simple and simultaneous handling of a large number of samples as a batch using micro-volumes of samples gave the assay the advantage of high throughput analysis, which is a serious demand in the pharmaceutical industry.

Regarding the Influence of Additives and Additional Plasma-Induced Chemical Ionization on Adduct Formation in ESI/IMS/MS

Ion mobility spectrometers (IMS) separate ions based on their ion mobility, which depends mainly on collision cross-section, mass, and charge of the ions. However, the performance is often hampered in electrospray ionization (ESI) by the appearance of multiple ion mobility peaks in the spectrum for the same analyte due to clustering and additional sodium adducts. In this work, we investigate the influence of solvents and buffer additives on the detected ion mobility peaks using ESI. Additionally, we investigate the effects of an additional chemical ionization (CI) induced by plasma ionization on the ions formed by electrospray. For this purpose, we coupled our high-resolution IMS with a resolving power of R_p = 100 to a time-of-flight mass spectrometer. Depending on the analyte and the chosen additives, the ionization process can be influenced during the electrospray process. For the herbicide isoproturon, the addition of 5 mM sodium acetate results in the formation of the sodium adduct [M + Na]⁺, which is reflected in the ion mobility K₀ of 1.22 cm²/(V·s). In contrast, the addition of 5 mM ammonium acetate yields the protonated species [M + H]⁺ and a correspondingly higher K₀ of 1.29 cm²/(V·s). In some cases, as with the herbicide pyrimethanil, the addition of sodium acetate can completely suppress ionizations. By carefully choosing the solvent additive for ESI-IMS or additional CI, the formation of different ion mobility peaks can be observed. This can facilitate the assignment of ions to ion mobility peaks using IMS as a compact, stand-alone instrument, e.g., for on-site analysis.

A thin biofilm of chitosan as a sorptive phase in the rotating disk sorptive extraction of triclosan and methyl triclosan from water samples

The features and nature of the sorptive phase may be the stage that determines the scope of microextraction techniques. In search of new alternatives, materials of natural origin have recently been explored to establish greener analytical strategies. Based on that search, this research proposes the use of chitosan as a sorptive phase, which was assessed in the rotating disk sorptive extraction of emerging contaminants from aqueous systems. Chitosan is a biopolymer of animal origin that is usually found in the shells of crustaceans. The main characteristic of this material is the presence of a high number of nitrogenous groups, which gives it high reactivity, but its main disadvantage is associated with its high swelling capacity. In this research, chitosan was crosslinked with a low concentration of glutaraldehyde to form thin films that were easily immobilized on the surface of the rotating disk. The main advantage of this modification is the considerable decrease in the swelling capacity, which prevents loss and rupture of the sorbent during high rotation of the disk. In addition, it not only improved the physical characteristics of chitosan but also increased its extraction capacity. With regard to its use as a sorptive phase, all the variables associated with the microextraction of the analytes were studied, and optimal variables were found to be: pH 4, 20% NaCl (salting out effect), 30-45 min as equilibrium time and elution of analytes with a mixture of methanol:ethyl acetate (1:1). Validation of the methodology for the determination of methyl triclosan and triclosan was carried out, and relative recoveries between 89 and 96% and relative standard deviations less than 14% were found. The detection limits were 0.11 and 0.20 μg L^-1, respectively. Through its application in real samples (natural and residual waters), triclosan was quantified between 0.7 and 1.3 μg L^-1. Finally, the "green" properties of the phase were evaluated, demonstrating that it is reusable for at least three cycles and biodegradable. Compared to its efficiency with a commercial phase (in this case, the styrene divinyl benzene phase), the proposed biosorbent provided a similar and even higher sorptive capacity (depending on the analyte).

A green methodology for the determination of cocaine in camouflaged samples

A methodology based on the ultrasound-assisted extraction with ethanol and the dry film attenuated total reflectance infrared spectroscopy (DF-ATR-FTIR) measurement of extracts has been developed for a fast evaluation of non-conventional ("exotic") solid-sized cocaine samples. The method provides quantitative results in less than three minutes with a limit of detection in the solid sample of 1.6 μg g-1 of cocaine with a variation coefficient lower than 7%. Results found for seized samples of different natures were compared with those obtained by a reference gas chromatography method and the greenness of the whole proposed procedure was evaluated and compared using the analytical eco-scale, green analytical procedure index (GAPI), and analytical greenness metric (AGREE). The green evaluation of the proposed methodology provided green scores by considering different evaluation criteria.

Development of a detection method for 10 non-steroidal anti-inflammatory drugs residues in four swine tissues by ultra-performance liquid chromatography with tandem mass spectrometry

The ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) detection method was developed for the residues of 10 NSAIDs (salicylic acid, acetylsalicylic acid, acetaminophen, diclofenac, tolfenamic acid, antipyrine, flunixin meglumine, aminophenazone, meloxicam, metamizole sodium) in swine muscle, liver, kidney, and fat. Swine tissue samples were extracted by phosphorylated acetonitrile with the addition of an appropriate amount of internal standard working solution, defatted with acetonitrile-saturated n-hexane, and purified by Hydrophile-Lipophile Balance (HLB) solid-phase extraction column, then separated by UPLC BEH shield RP₁₈ column with 0.1% formic acid in water/0.1% formic acid in acetonitrile with gradient elution, which was detected in the multiple reaction monitoring (MRM) modes. The correlation coefficient of the standard curve equation is greater than 0.99, and the coefficient of variation within and between batches is less than 14.4%. We evaluated the analytical method using two green assessment tools. The method established in this study met the requirements of NSAID residue analysis and provides analytical tools for determining and confirming NSAIDs in swine tissue samples. This is the first report on the simultaneous determination of 10 NSAIDs in four swine tissues by the UPLC-MS/MS method and accurate quantification using deuterated internal standards.