Application of hollow fiber liquid phase microextraction and dispersive liquid–liquid microextraction techniques in analytical toxicology

Spectrophotometric determination of o-phenylphenol in canned drinks using three-phase hollow-fiber liquid phase microextraction

A three-phase hollow-fiber liquid phase microextraction for o-phenylphenol (OPP) determination was developed. 1-octanol was employed as the organic phase, impregnated within the pores of the hollow fiber wall which was immersed in the sample solution, serving as a donor phase. OPP in the sample solution was extracted via octanol in the fiber pores into NaOH, which acted as the acceptor phase in the lumen of the fiber. The extracted OPP was then subjected to spectrophotometric detection at 712 nm using the indophenol blue reaction. The developed method showed a linear calibration curve (0.002-0.040 mg L-1) with high sensitivity (5.75 L mg-1), low limit of detection (0.31 μg L-1), and high recovery (73.6-94.8 %). Intra-day and inter-day precision at 2.1 μg L-1 OPP were 7.4 % (n = 12) and 10.9 % (n = 4) relative standard deviations, respectively. The determined OPP in various canned drinks was found to be between 2.0 and 17.8 μg L-1 using the developed method.

Hollow-fiber liquid phase microextraction for determination of fluoxetine in human serum by nano-liquid chromatography coupled to high resolution mass spectrometry

Therapeutic drug monitoring (TDM) is a personalized care tool based on the determination of a target drug concentration in human serum. An antidepressant drug of interest for such investigations is fluoxetine (FXT), due to a severe impact of genetic polymorphisms on its metabolism. A bioanalytical method employed for TDM purposes must exhibit satisfactory selectivity and detectability, which becomes more difficult due to highly complex biological matrices. In this study, a highly selective bioanalytical method for the determination of FXT in human serum is proposed, which provides excellent clean-up efficiency based on a low cost hollow fiber liquid-phase microextraction (HF-LPME) sample preparation step and nano-liquid chromatography coupled to high-resolution mass spectrometry (nano-LC-HRMS). HF-LPME was performed using a two-phase "U" configuration, with 6 cm fiber, 20 µL of 1-octanol acting as supported liquid membrane, and ammonium hydroxide (pH 10) as the donor phase with NaCl (10 % m/v) and methanol (5 % v/v) as additives, requiring only 250 µL of the sample. The procedure was conducted for 30 min under a 750 rpm stirring rate. Gradient elution was carried out employing an acetonitrile-water as mobile phase, the composition of 30:70 to 100:00 (v/v) for 15 min, using formic acid 0.1 % (v/v) as an additive. MS1 was acquired in an Orbitrap mass analyzer, while MS2 was acquired in a linear trap quadrupole. Satisfactory linearity (Pearson's r = 0.99709) was obtained for a concentration range of 0.02 to 2.5 µg mL-1, which is compatible with the therapeutic and toxic range for FXT. The developed method presents adequate precision (1.61 to 7.45 %) and accuracy (95 to 114 %) and allows the dilution of high concentration samples in a 1:4 ratio (v/v), enabling its application for forensic serum samples. To our knowledge, this is the first study reporting a method based on HF-LPME and nano-LC-HRMS with any analytical purpose, especially with a TDM focus.

Deep eutectic solvents for the determination of endocrine disrupting chemicals

The harmful effects of endocrine disrupting chemicals (EDCs) to humans and other organisms in the environment have been well established over the years, and more studies are ongoing to classify other chemicals that have the potential to alter or disrupt the regular function of the endocrine system. In addition to toxicological studies, analytical detection systems are progressively being improved to facilitate accurate determination of EDCs in biological, environmental and food samples. Recent microextraction methods have focused on the use of green chemicals that are safe for analytical applications, and present very low or no toxicity upon disposal. Deep eutectic solvents (DESs) have emerged as one of the viable alternatives to the conventional hazardous solvents, and their unique properties make them very useful in different applications. Notably, the use of renewable sources to prepare DESs leads to highly biodegradable products that mitigate negative ecological impacts. This review presents an overview of both organic and inorganic EDCs and their ramifications on human health. It also presents the fundamental principles of liquid phase and solid phase microextraction methods, and gives a comprehensive account of the use of DESs for the determination of EDCs in various samples.

High-throughput quantification of emerging "nitazene" benzimidazole opioid analogs by microextraction and UHPLC-MS-MS

Benzimidazole opioids, often referred to as nitazenes, represent a subgroup of new psychoactive substances with a recent increase in fatal overdoses in the USA and Europe. With a variety of analogs emerging on the illicit drug market, forensic laboratories are challenged to identify these potent drugs. We here present a simple quantitative approach for the determination of nine nitazene analogs, namely, clonitazene, etodesnitazene, etonitazene, etonitazepyne, flunitazene, isotonitazene, metodesnitazene, metonitazene and protonitazene in whole blood using liquid-phase microextraction and electromembrane extraction in a 96-well format and liquid chromatography-tandem mass spectrometry. Green and efficient sample preparation was accomplished by liquid-phase microextraction in a 96-well format and resulted in high extraction yields for all analytes (>81%). Here, blood diluted with buffer (1:1, %v) was extracted from a donor compartment across a thin organic liquid membrane and into an aqueous acceptor solution. The acceptor solution was collected and directly injected into the analysis platform. Chromatographic separation was accomplished with a biphenyl column, allowing for a baseline separation of the structural isomers isotonitazene and protonitazene before detection by multiple reaction monitoring. Validation was performed according to Scientific Working Group of Forensic Toxicology guidelines. The calibration range was from 0.5 to 50 nM (except for protonitazene and clonitazene from 0.1 nM) with good linearity and limits of detection down to 0.01 nM. An AGREEprep assessment was performed to evaluate sample preparation greenness, with a final score of 0.71. Nitazenes represent a current threat to public health, and analytical methods that cover a wide range of these analogs are limited. Here, the described method may assist in the detection of nitazenes in whole blood and prevent these substances from being missed in postmortem investigations.

An electromembrane microextraction-based green method for the determination of trace copper in natural waters

Driven by the search for an environmentally-friendly methodology, electromembrane extraction (EME) has recently emerged as a green and versatile tool for the analysis of trace pollutants in water samples, being mainly applied to the preconcentration and determination of organic compounds. Recently, EME has also shown its applicability to the analysis of inorganic species, allowing a considerable reduction in both reagent consumption and extraction times, and without loss of efficacy, in comparison with other liquid phase microextraction techniques. In this study, an EME system for trace copper analysis in natural waters has been optimised by the modified simplex method. A chemical modifier, di-2-pyridyl ketone benzoylhydrazone (dPKBH) was synthesized and dissolved in 1-nonanol, to be used as an organic phase impregnated into the pores of a polymeric hollow fibre. With only 15 min of extraction, an enrichment factor of 77.1 ± 10.8 was obtained for a wide salinity range (0-35), allowing its application in a variety of different waters, including seawater. Optimum operating conditions were a sample pH of 6.26, an electric potential of 95 V, 0.08 M nitric acid as the acceptor phase, 4.01 mM dPKBH in 1-nonanol as the organic phase and a stirring rate of 1500 rpm. A LOD of 0.004 μg L^-1 was obtained, and the system was successfully applied to the analysis of several water samples containing copper at low ppb levels (tap water and river water) or even at sub-ppb levels (seawater).

Hollow Fibre-Supported Liquid Membrane for the Determination of Sulfonamide Residues in Egg Samples

In this study, a three-phase hollow fibre-supported liquid membrane (HF-SLM) technique incorporated with high-performance liquid chromatography (HPLC) coupled with diode array detection (DAD) was developed for the extraction, clean-up, and determination of fifteen sulfonamide residues in chicken egg samples. The residues were extracted from the 5 mL sample solution of pH 2.5 into a thin layer of organic phase (1-octanol with 10% TOPO) immobilised in hollow fibre pores and then back-extracted into approximately 6 μL of aqueous phase (pH 13) located in the lumen of the hollow fibre. After extraction, 6 μL of the acceptor phase was injected into an HPLC instrument for subsequent analysis. Under optimum conditions, the limit of detection (LOD) and limit of quantification (LOQ) values ranged from 0.8–7.9 μg·kg−1 and from 2.4–21.0 μg·kg−1, respectively, linearity in the range of 5 1 000 μg·kg−1, and intra- and inter-day precision (%RSD) values at three concentration levels (50, 100, and 500 μg·L−1) ranged from 6.2–15.7%, 7.3–15.0%, and 7.3–14.6%; and 6.4–17.4%, 4.3–16.2%, and 8.3–16.5%, respectively, were obtained. The accuracy of the method, expressed as percentage recovery, was in the range of 71.0–98.7%, with corresponding %RSD (n = 6) values ranging from 1.9–9.9% being obtained. The developed method provided enrichment factors in the range of 17.1 to 541.4. The applicability of the proposed method was also evaluated by analysing egg samples, which were randomly collected from local supermarkets located in Gauteng Province, South Africa. The results obtained revealed that the developed method has the potential to be used as an alternative method for the determination of sulfonamide residues in egg and related complex samples.

Dispersive liquid-liquid microextraction coupled with microfluidic paper-based analytical device for the determination of organophosphate and carbamate pesticides in the water sample

A microfluidic paper-based analytical device (µ-PAD) is a promising new technology platform for the development of extremely low-cost sensing devices. However, it has low sensitivity that might not enable to measure maximum allowable concentration of various pollutants in the environment. In this study, a dispersive liquid-liquid microextraction (DLLME) was developed as a preconcentration method to enhance the sensitivity of the µ-PAD for trace analysis of selected pesticides. Four critical parameters (volume of n-hexane and acetone, extraction time, NaCl amount) that affect the efficiency of DLLME have been optimized using response surface methodology. An acceptable mean recovery of 79-97% and 83-93% was observed at 1 µg L^-1 and 5 µg L^-1 fortification level, respectively, with very good repeatability (2.2-6.01% RSD) and reproducibility (5.60-10.41% RSD). Very high enrichment factors ranging from 317 to 1471 were obtained. The limits of detection for the studied analytes were in the range of 0.18-0.41 µg L^-1 which is much lower than the WHO limits of 5-50 µg L^-1 for similar category of analytes. Therefore, by coupling DLLME with µ-PAD, a sensitivity that allows to detect environmental threat and also that surpassed most of the previous reports have been achieved in this study. This implies that the preconcentration step has a paramount contribution to address the sensitivity problem associated with µ-PAD.

Trends in hollow fibre liquid phase microextraction for the preconcentration of pharmaceutically active compounds in aqueous solution: A case for polymer inclusion membrane

Low concentrations of pharmaceutically active compounds have been reported in samples from highly complex aqueous environments. Due to their low concentrations, efficient sample pretreatment methods are needed to clean samples and concentrate the compounds of interest prior to instrumental analysis. Hollow fibre liquid-phase microextraction (HF-LPME) is an effective alternative to conventional techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) because it consumes less organic solvent and is less labour intensive with a short extraction time. HF-LPME involves the preconcentration and mass transfer of target analytes from an aqueous sample into an acceptor solution in the lumen of the fibre using a supported liquid membrane (SLM) impregnated in the hollow fibre pores. However, despite the high contaminant selectivity, reproducibility, and enrichment that HF-LPME offers, this technique is limited by membrane instability. Although several advances have been made to address membrane instability, they are either too costly or not feasible for industrial application. Hence, hollow fibre polymer inclusion membrane liquid-phase microextraction (HF-PIM-LPME) was introduced to ameliorate membrane instability. This new approach uses ionic liquids (ILs) as a green solvent, and has demonstrated high membrane stability, good contaminant enrichment, and similar selectivity and reproducibility to HF-SLM-LPME. Hence, this review aims to raise awareness of HF-PIM-LPME as a viable alternative for the selectivity and preconcentration of pharmaceuticals and other contaminants in aquatic environments.

Enrichment of tetracycline residues from honey samples using carrier-mediated hollow fibre liquid-phase micro-extraction and quantification by LC-Q-TOF/MS

BACKGROUND

In this study, development and validation of a simple, miniaturized and, environmentally friendly carrier-mediated three-phase hollow-fibre liquid-phase micro-extraction (HFLPME) technique was investigated for the enrichment of tetracycline residues in honey samples. The extracts were analysed using UV-visible spectrophotometry and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS). Parameters affecting the extraction efficiency of HFLPME such as pH of the donor and acceptor solutions, salt addition, agitation speed and extraction time were optimized.

RESULTS

The calibration curves showed good linearity, in the range of 1-100 μg kg^-1 with correlation coefficients ranging between 0.9943 and 0.9992, under the optimized conditions. Recoveries of blank honey samples at three spiking levels (1, 10 and 20 μg kg^-1 ) ranged from 81.2% to 107.5%. Relative standard deviations for the precision of the method were less than 15.0%. Limits of detection and limits of quantification were in the range of 0.0861-0.2628 μg kg^-1 and 0.2610-0.7964 μg kg^-1 , respectively. Finally, the proposed method was successfully applied in the extraction of five tetracyclines from honey samples. Doxycycline residue detected in one of the commercial honey samples was below the limit of quantification.

CONCLUSION

Because of the advantages offered by HFLPME, this method can be employed as an alternative to conventional extraction techniques for the clean-up and pre-concentration of antibiotics in complex matrices, including food samples. © 2021 Society of Chemical Industry.

Solid-phase optimisation for simultaneous determination of thirteen pharmaceuticals in Ethiopian water samples with HPLC-DAD detection: an initial assessment

Pharmaceutical consumption is increasing worldwide as it is essential to treat and prevent health issues but they end up in the environment. However, in many African countries like Ethiopia, the status of these compounds in various environmental samples is not very well known. In this study, a simple method for the extraction and determination of thirteen pharmaceutical compounds of different therapeutic classes in water samples using solid-phase extraction and HPLC-DAD was developed. Different parameters affecting extraction were optimised and obtained as hydrophilic-lipophilic balance (HLB) extraction cartridge, water sample pH of 5, elution solvent of 2% formic acid in water with methanol (20:80%, v/v), a sample volume of 150 mL and addition of 0.5% w/v EDTA in the sample. The limits of detection and quantification of the optimised method were in the range of 0.1-0.8 µg/L and 0.2-2.6 µg/L, respectively. The relative recovery in the spiked environmental water sample was in the range of 70-117% except for amoxicillin and acetylsalicylic acid in influent wastewater. The precision for all ranged from 0.3 to 11%. The proposed method was successfully tested for the detection and quantification of different environmental water samples collected from Addis Ababa, Ethiopia. Trimethoprim, caffeine and albendazole concentrations of 7.8 (1.1), 3.2 (0.4) and 2.1 (0.1) µg/L were quantified in hospital wastewater, respectively. The concentration of norfloxacin was found to be below the limit of quantification in the same water. Trimethoprim and ciprofloxacin were also found in the sewage treatment plant influent sample at a concentration of 0.5 (0.02) and 0.3 (0.01) µg/L, respectively.

Determination of Organophosphorus Pesticides Using Solid-Phase Extraction Followed by Gas Chromatography-Mass Spectrometry

In this study, a method was developed for determination of three organophosphorus pesticides (OPPs) using graphene aerogel solid-phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC-MS). The experimental results showed that the target analytes could be extracted on packed SPE cartridges and then eluted with tetrahydrofuran. The final sample solution was analyzed by GC-MS, which demonstrated good linearity between 0.5 and 500 μg L-1 with a correlation coefficient (r) of 0.9991-0.9998. The limits of detection (S/N = 3) and the limits of quantification (S/N = 10) for the three OPPs ranged from 0.38 to 0.82 μg L-1 and 1.32 to 2.75 μg L-1, respectively. The accuracy of the proposed method was evaluated by measuring the recovery of the spiked samples, which ranged from 91.2 to 103.7%, with relative standard deviations of 2.1-7.2%. This method was successfully applied for the determination of the target analytes in water samples taken from tap, wetlands and canal water.

Application of Microextraction-Based Techniques for Screening-Controlled Drugs in Forensic Context-A Review

The analysis of controlled drugs in forensic matrices, i.e., urine, blood, plasma, saliva, and hair, is one of the current hot topics in the clinical and toxicological context. The use of microextraction-based approaches has gained considerable notoriety, mainly due to the great simplicity, cost-benefit, and environmental sustainability. For this reason, the application of these innovative techniques has become more relevant than ever in programs for monitoring priority substances such as the main illicit drugs, e.g., opioids, stimulants, cannabinoids, hallucinogens, dissociative drugs, and related compounds. The present contribution aims to make a comprehensive review on the state-of-the art advantages and future trends on the application of microextraction-based techniques for screening-controlled drugs in the forensic context.

Application of microextraction techniques in alternative biological matrices with focus on forensic toxicology: a review

The interest in alternative biological matrices (e.g., hair and saliva) for forensic toxicology analysis has increased, and recent developments in sample preparation have targeted rapid, cheap, efficient and eco-friendly methods, including microextraction techniques. For this review, we have gathered information about these two hot topics. We discuss the composition, incorporation of analytes and advantages and disadvantages of different biological matrices, and also present the operation principles of the most reported microextraction procedures and their application in forensic toxicology. The outcome of this review may encourage future forensic researches into alternative samples and microextraction techniques.

Modern microextraction techniques for natural products

Natural product analysis has gained wide attention in recent years, especially for herbal medicines, which contain complex ingredients and play a significant clinical role in the therapy of numerous diseases. The constituents of natural products are usually found at low concentrations, and the matrices are complex. Thus, the extraction of target compounds from natural products before analysis by analytical instruments is very significant for human health and its wide application. The commonly used traditional extraction methods are time-consuming, using large amounts of sample and organic solvents, as well as expensive and inefficient. Recently, microextraction techniques have been used for natural product extraction to overcome the disadvantages of conventional extraction methods. In this paper, the successful applications of and recent developments in microextraction techniques including solvent-based and sorbent-based microextraction methods, in natural product analysis in recent years, especially in the last 5 years, are reviewed for the first time. Their features, advantages, disadvantages, and future development trends are also discussed.

Application of Hollow Fibre-Liquid Phase Microextraction Technique for Isolation and Pre-Concentration of Pharmaceuticals in Water

In this article, a comprehensive review of applications of the hollow fibre-liquid phase microextraction (HF-LPME) for the isolation and pre-concentration of pharmaceuticals in water samples is presented. HF-LPME is simple, affordable, selective, and sensitive with high enrichment factors of up to 27,000-fold reported for pharmaceutical analysis. Both configurations (two- and three-phase extraction systems) of HF-LPME have been applied in the extraction of pharmaceuticals from water, with the three-phase system being more prominent. When compared to most common sample preparation techniques such as solid phase extraction, HF-LPME is a greener analytical chemistry process due to reduced solvent consumption, miniaturization, and the ability to automate. However, the automation comes at an added cost related to instrumental set-up, but a reduced cost is associated with lower reagent consumption as well as shortened overall workload and time. Currently, many researchers are investigating ionic liquids and deep eutectic solvents as environmentally friendly chemicals that could lead to full classification of HF-LPME as a green analytical procedure.

MASS SPECTROMETRY ANALYSIS OF DRUGS OF ABUSE: CHALLENGES AND EMERGING STRATEGIES

Mass spectrometry has been the "gold standard" for drugs of abuse (DoA) analysis for many decades because of the selectivity and sensitivity it affords. Recent progress in all aspects of mass spectrometry has seen significant developments in the field of DoA analysis. Mass spectrometry is particularly well suited to address the rapidly proliferating number of very high potency, novel psychoactive substances that are causing an alarming number of fatalities worldwide. This review surveys advancements in the areas of sample preparation, gas and liquid chromatography-mass spectrometry, as well as the rapidly emerging field of ambient ionization mass spectrometry. We have predominantly targeted literature progress over the past ten years and present our outlook for the future. © 2020 Periodicals, Inc. Mass Spec Rev.

Hollow fiber-based liquid phase microextraction followed by analytical instrumental techniques for quantitative analysis of heavy metal ions and pharmaceuticals

Hollow-fiber liquid-phase microextraction (HF-LPME) and electromembrane extraction (EME) are miniaturized extraction techniques, and have been coupled with various analytical instruments for trace analysis of heavy metals, drugs and other organic compounds, in recent years. HF-LPME and EME provide high selectivity, efficient sample cleanup and enrichment, and reduce the consumption of organic solvents to a few micro-liters per sample. HF-LPME and EME are compatible with different analytical instruments for chromatography, electrophoresis, atomic spectroscopy, mass spectrometry, and electrochemical detection. HF-LPME and EME have gained significant popularity during the recent years. This review focuses on hollow fiber based techniques (especially HF-LPME and EME) of heavy metals and pharmaceuticals (published 2017 to May 2019), and their combinations with atomic spectroscopy, UV-VIS spectrophotometry, high performance liquid chromatography, gas chromatography, capillary electrophoresis, and voltammetry.

Critical review of micro-extraction techniques used in the determination of polycyclic aromatic hydrocarbons in biological, environmental and food samples

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous environmental contaminants and their accurate determination is very important to human health and environment safety. In this review, sorptive-based micro-extraction techniques [such as Solid-Phase Micro-extraction (SPME), Stir Bar Sorptive Extraction (SBSE), Micro-extraction in Packed Sorbent (MEPS)] and solvent-based micro-extraction [Membrane-Mediated Liquid-Phase Micro-extraction (MM-LPME), Dispersive Liquid-Liquid Micro-extraction (DLLME), and Single Drop Micro-extraction (SDME)] developed for quantification of PAHs in environmental, biological and food samples are reviewed. Moreover, recent micro-extraction techniques that have been coupled with other sample extraction strategies are also briefly discussed. The main objectives of these micro-extraction techniques are to perform extraction, pre-concentration and clean up together as one step, and the reduction of the analysis time, cost and solvent following the green chemistry guidelines.

Simultaneous analysis of multiclass contaminants of emerging concern in sediments by liquid chromatography with tandem quadrupole mass spectrometry

A quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction and simultaneous dispersive solid-phase extraction (dSPE) clean-up method was developed for contaminants of emerging concern (CECs) in sediment samples. Hydration with a phosphate buffer (pH 2.0) and salting out with NaCl and MgSO₄ facilitated the extraction and liquid-liquid portioning of the aqueous and organic phases. Cleanup of the extracts was achieved by florisil and C18 (1:1) sorbents in dSPE with minimal compromise of the analytes. The extracts were clean enough for determination by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The procedure was validated for preservatives, blood lipid regulators, analgesics and anti-inflammatory drugs, plasticizers, and other classes of CECs in sediment matrix spiked at 6 levels between 1- and 40-fold concentrations for CECs of varying analytical sensitivities. The recovery values were generally between approximately 27 and 120% and the relative standard deviation (%RSD) values were below 20% at 10- , 20- , and 40-fold spiking levels, albeit the recoveries for some analytes dropped at low spike concentrations. The method showed high sensitivity where the method detection limits (MDLs) were at low ppb levels for the majority of the analytes that ranged between 0.002 and 1.93 µg/kg. The method performance was also compared with well-established US Environmental Protection Agency (USEPA) Method 1694 by analyzing sediment samples collected from Yundang Lagoon (Xiamen, China) with field-incurred CEC residues. The sediment samples were detected with residues of parabens, gemfibrozil, ketoprofen, naproxen, fenoprofen, diclofenac, miconazole, carbamazepine, benzophenon-3, glibenclamide, sildinafil citrate, and some bisphenol analogues. Environ Toxicol Chem 2019;38:1409-1422. © 2019 SETAC.

Functionalized Multi Walled Carbon Nanotubes-Reinforced Hollow Fiber Solid/Liquid Phase Microextraction and HPLC-DAD for Determination of Phenazopyridine in Urine

Introduction:

A sensitive analytical method based on functionalized multi walled carbon nanotubes reinforced hollow fiber solid/liquid phase microextraction (F-MWCNTs-HF-SLPME) forwarded with HPLC-DAD for analyzing phenazopyridine from urine is presented.

Materials and Methods:

The extraction of phenazopyridine is performed using specially designed FMWCNTs- HF-SLPME device constructed as follows: the functionalized multi walled carbon nanotubes (F-MWCNTs) were immobilized into the pores of 2.5 cm hollow fiber micro-tube using capillary forces and ultrasonication, then, the lumen of the micro-tube was filled with 1-octanol with two ends sealed. Subsequently, the device was placed into 10-mL of urine sample containing the analyte with agitation. After ending extraction, the device was removed, rinsed, sonicated in 250 µL of organic solvent and analyzed directly by the separation system.

Results and Conclusion:

Different parameters affecting the performance of the developed method were optimized. The method showed good linearity with (R2) 0.999 and good repeatability with (RSDs) from 3.7 to 0.9% at analyte concentration ranged from 0.01 to 10 µg L-1 of spiked urine samples. The limit of detection/ quantitation, LODs/LOQs was 0.02/0.09 µg L-1. In comparison with reference methods, the developed method is considered as a promising microextraction technique for determination of trace phenazopyridine in human urine using a common HPLC without further cleanup procedures.

Salting-out assisted liquid-liquid extraction for the determination of ciprofloxacin residues in water samples by high performance liquid chromatography-diode array detector

Background

The occurrence of emerging pollutants like pharmaceuticals and related compounds in the aquatic and terrestrial environments is of increasing concern. Ciprofloxacin is one of the pharmaceuticals which is active against a wide range of bacteria. The main objective of this research is to develop a simple method for the extraction and determination of ciprofloxacin residues in environmental water samples.

Results

A salting-out assisted liquid-liquid extraction (SALLE) method for the determination of ciprofloxacin in water samples by high-performance liquid chromatography with diode array detector (HPLC-DAD) was developed. The calibration curve was linear over the range of 0.1-100 μg/L with coefficient of determination (r²) of 0.9976. The limits of detection (LOD) and quantification (LOQ) of the method were 0.075 and 0.25 µg/L, respectively. The reproducibility in terms of relative standard deviation (% RSD) was less than 10%. The applicability of the developed method was investigated by analyzing tap water, bottled mineral water and waste water and demonstrated satisfactory recoveries in the ranges of 86.4-120%.

Conclusion

The method offered a number of features including wide linear range, good recovery, short analysis time, simple operation process and environmental friendly. The developed method can be utilized as an attractive alternative for the determination of ciprofloxacin residues in environmental water matrices.

Miniaturized sample preparation methods for saliva analysis

Saliva, as the first body fluid encountering with the exogenous materials, has good correlation with blood and plays an important role in bioanalysis. However, saliva has not been studied as much as the other biological fluids mainly due to restricted access to its large volumes. In recent years, there is a growing interest for saliva analysis owing to the emergence of miniaturized sample preparation methods. The purpose of this paper is to review all microextraction methods and their principles of operation. In the following, we examine the methods used to analyze saliva up to now and discuss the potential of the other microextraction methods for saliva analysis to encourage research groups for more focus on this important subject area.

New passive sampling device for effective monitoring of pesticides in water

The extensive use of pesticides promotes environmental contamination, mainly in surface and ground waters. However, they remain at very low concentration and present wide degradation level requiring the use of efficient devices for pesticides passive sampling. In this study, a new in situ passive sampling device was developed for monitoring and estimating time-weighted average (TWA) of pesticides in waters. The device was made with simple, recyclable and cheap materials. The sampling system involves the liquid phase microextraction technique with hollow fiber in two-phases mode. Pesticides determination was done by gas chromatography coupled to mass spectrometry. The method was optimized and validated for the determination of 29 pesticides in water, showing good linearity in the range between 0.012 and 40.00 μg L^-1 with determination coefficients of R² > 0,9649. Limit of detection (LOD) ranged from 0.009 to 0.557 μg L^-1 and limit of quantification (LOQ) from 0.012 to 0.802 μg L^-1. The recoveries of spiked pesticides in water samples were in the range from 96 to 130%. The method was applied to forty environmental water samples collected at São Francisco river basin, Brazil. The highest detection frequency was found for the pesticides 4,4-DDE, 4,4-DDD and propazine. They were detected in more than 20 percent of the samples.

Determination of synthetic pharmaceutical adulterants in herbal weight gain supplements sold in herb shops, Tehran, Iran

BACKGROUND

Nowadays with the growing popularity of herbal remedies across the world, large sections of population rely on herbal drug practitioners for their primary care. Therefore there is a need to ensure about the safety of herbal drugs and to detect adulteration with undeclared active pharmaceutical ingredients. Herbal drugs are used as first-line drug therapy in some instances. Unfortunately even if there are claims as to be natural, undeclared active pharmaceutical ingredients have been detected in these supplements.

OBJECTIVES

The purpose of the present study was to analyse herbal weight gain drugs collected from herb shops located in Tehran, Iran to detect hidden pharmaceutical ingredients using UHPLC and GC/MS instrumentations.

METHODS

Sixty herbal drugs advertised as weight gain supplements were gathered from herb shops Tehran province, Iran. All samples were analysed from analytical toxicology point of view to detect undeclared active pharmaceutical ingredients. Method was validated for quantitative analysis of cyproheptadine and dexamethasone.

RESULTS

Method validity parameters showed good results for quantitative analysis of pharmaceutical ingredients. Cyproheptadine, dexamethasone, sildenafil, tramadol, caffeine and acetaminophen were detected in herbal weight gain drugs. Analysed dosage forms contained cyproheptadine and dexamethasone in concentrations higher than therapeutic doses. Quantitative analysis of contaminated drugs showed that the content of pharmacologic ingredients were 0.2-67 and 5.5-10.1 mg/tablet or capsule for cyproheptadine and dexamethasone respectively.

CONCLUSIONS

Despite natural supplements producers' claim, herbal weight gain drugs were not natural at all. Undeclared active pharmaceutical ingredients can predispose patients to health problems and even life-threatening situations. Graphical Abstract ᅟ.

Cetyl-alcohol-reinforced hollow fiber solid/liquid-phase microextraction and HPLC-DAD analysis of ezetimibe and simvastatin in human plasma and urine

A new cetyl-alcohol-reinforced hollow fiber solid/liquid-phase microextraction (CA-HF-SLPME) followed by high-performance liquid chromatography-diode array detection (HPLC-DAD) method was developed for simultaneous determination of ezetimibe and simvastatin in human plasma and urine samples. To prepare the CA-HF-SLPME device, the cetyl-alcohol was immobilized into the pores of a 2.5 cm hollow fiber micro-tube and the lumen of the micro-tube was filled with 1-octanol with the two ends sealed. Afterwards, the prepared device was introduced into 10 mL of the sample solution containing the analytes with agitation. Under optimized conditions, calibration curves plotted in spiked plasma and urine samples were linear in the ranges of 0.363-25/0.49-25 μg L^-1 for ezetimibe/simvastatin and 0.193-25/0.312-25 μg L^-1 for ezetimibe/simvastatin in plasma and urine samples, respectively. The limit of detection was 0.109/0.174 μg L^-1 for ezetimibe/simvastatin in plasma and 0.058/0.093 μg L^-1 for ezetimibe/simvastatin in urine. As a potential application, the proposed method was applied to determine the concentration of selected analytes in patient plasma and urine samples after medication and satisfactory results were achieved. In comparison with reference methods, the CA-HF-SLPME-HPLC-DAD method demonstrates considerable potential in the biopharmaceutical analysis of selected drugs.