Development of a fast and simple gas chromatographic protocol based on the combined use of alkyl chloroformate and solid phase microextraction for the assay of polyamines in human urine

A direct immersion-solid-phase microextraction method for the automated determination of 3- to 6-ring polycyclic aromatic hydrocarbons in saliva by gas-chromatography-tandem mass spectrometry

This work presents a novel method for the analysis of polycyclic aromatic hydrocarbons (PAHs) in saliva samples using solid phase microextraction (SPME) coupled with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS). The protocol utilizes the latest commercially available overcoated fiber (PDMS/DVB/PDMS) for direct immersion extraction of the target analytes, enabling the determination of thirteen PAHs, including low-volatile compounds. The SPME extraction method was optimized using a central composite design (CCD). The evaluation of the fiber coating's robustness over time demonstrated excellent extraction performance with no significant degradation. The validation procedure confirmed good performance for all parameters, with LOQ values (100 ng/L for ten analytes and 500 ng/L for three analytes) comparable to other chromatographic methods. The environmental impact of the protocol was objectively assessed using two recently proposed metrics: the Green Analytical Procedure Index (GAPI) and the Analytical Greenness metric for sample preparation (AGREEprep). Both metrics indicated good overall environmental friendliness, with AGREEprep providing a satisfactory comprehensive score despite the use of highly impactful instrumentation. These characteristics make the developed method suitable for routine analysis in environmental and epidemiological monitoring.

Development of a new continuous homogenous liquid phase microextraction procedure based on in-situ preparation of deep eutectic solvent; application in the analysis of aliphatic amines in urine samples by GC-MS

In the present work, a new microextraction procedure combined with gas chromatography-mass spectrometry has been developed for the analysis of several aliphatic amines from urine sample. The sample preparation method was a continuous homogenous liquid phase microextraction that was based on in-situ preparation of 4-chlorophenol: choline chloride deep eutectic solvent. The deep eutectic solvent was prepared by passing the mixture of related compounds through a syringe barrel filled with exothermic salts (calcium chloride and potassium bromide). The released heat by dissolving the salts and increasing the solution ionic strength assists the formation of the deep eutectic solvent. The influence of various factors on the efficiency of the proposed procedure including salts amount, flow rate, pH, salting-out effect, and extraction solvent volume was studied. The calibration curves were linear broadly over the concentration range of 1.2-250 ng mL-1 with coefficient of determinations ≥0.996. The enrichment factors were in the range of 188-246 and the limits of detection and quantification were 0.16-0.37 and 0.56-1.2 ng mL-1, respectively. Based on the results, the offered method was sensitive, rapid, eco-friendly, and efficient for extracting and determining aliphatic amines in urine samples.

A protocol based on solid phase microextraction -gas chromatography-tandem mass spectrometry for the monitoring of parabens and bisphenols in human saliva

The herein presented work aims to the development of an easy method for the quantitative determination of parabens and bisphenols in human salivabased on the use of methyl chloroformate as a derivatizing agent, followed by solid-phase microextraction (SPME) and gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) analysis with selected reaction monitoring (SRM). Using multivariate analysis, two derivatization strategies were compared and optimized, demonstrating that the use of methyl chloroformate led to better sensitivity than the classical derivatization by acetic anhydride. Good performance in the sorption process of the derivatized target analytes was obtained using the most recent commercialized overcoated fiber (PDMS/DVB/PDMS). The validation procedure of the final protocol led to satisfactory results in terms of linearity, limit of quantitation, accuracy, and precision. All parabens were quantified from 10 ng/L using the developed method, except for methylparaben, which was quantified from 100 ng/L along with all bisphenols. Intra- and inter-day accuracy and intra- and inter-day precision can be considered satisfactory for all analytes (values between 73% and 118%), except for the inter-day accuracy of BPF. Quite good results also in terms of matrix effect were obtained for the target compounds (range 71% to 118%, RSD% less than 13.6%), except for BPA at the middle concentration and MeP at the lowest concentration. The greenness of the method was evaluated and the results indicated that our approach is more eco-friendly than previously published methods. Based on its characteristics, the presented method can be considered a suitable approach to determine parabens and bisphenols in routine analysis for biomonitoring purposes.

A review of bioanalytical applications of microextraction techniques combined with derivatization

Microextraction techniques have attracted the attention of many researchers working in the field of bioanalysis due to their unique advantages, mainly in downsizing the scale of sample preparation steps. In parallel, analytical derivatization offers a powerful combination in terms of additional sensitivity, selectivity and compatibility with modern separation techniques. The aim of this review is to discuss the most recent advances in bioanalytical sample preparation based on the combination of microextraction and analytical derivatization. Both innovative fundamental reports and analyte-targeted applications are included and discussed. Dispersive liquid-liquid extraction and solid-phase microextraction are the most common techniques that typically combined with derivatization, while the development of novel and greener protocols is receiving substantial consideration in the field of analytical chemistry.

Assessment of benzothiazoles, benzotriazoles and benzenesulfonamides in environmental waters using an optimized combination of microextraction by packed sorbent with programmed temperature vaporization-gas chromatography tandem-mass spectrometry

This work proposes a new method for the quantification of benzothiazoles (BTs), benzotriazoles (BTRs), and benzenesulfonamides (BSAs) in tap water, river water, and wastewater. The protocol involved the use of microextraction by packed sorbent (MEPS), applied for the first time for the extraction of the target analytes, combined with programmed temperature vaporization-gas chromatography-triple quadrupole mass spectrometry (PTV-GC-QqQ-MS). Considering the synergism between MEPS extraction and PTV injection, the experimental variables affecting their performance were simultaneously optimized by "experimental design", while principal component analysis (PCA) was used to find the overall optimal working conditions. Response surface methodology was used to gain a comprehensive understanding of the effects of working variables on method performance. The developed method achieved very good linearities and satisfactory intra- and inter-day accuracies and precisions. The protocol permitted the detection of the target molecules with limit of detection (LODs) values between 0.005 and 0.85 μg/L. The green character of the procedure was evaluated using three metrics: "Analytical Eco-Scale", "Green Analytical Procedure Index" (GAPI), and "Analytical Greenness metric for sample preparation (AGREEprep). The satisfactory results obtained with real water samples demonstrate the applicability of the method for monitoring campaigns and exposome studies.

Determination of polyamines in urine via electrospun nanofibers-based solid-phase extraction coupled with GC-MS and application to gastric cancer patients

The simultaneous determination of polyamines and their metabolites in urine samples was achieved by gas chromatography-mass spectrometry in the selected ion monitoring mode. After conjugating with the ion-pair reagent bis-2-ethylhexylphosphate in the aqueous phase, the polyamines in the samples were extracted with polystyrene nanofiber-based packed-fiber solid-phase extraction followed by a derivatization step using pentafluoropropionyl anhydride. With optimal conditions, all analytes were separated well. For analytes of putrescine, cadaverine, N-acetylputrescine, and N-acetylcadaverine, the linearity was good in the range of 0.05-500 μmol/L (R²  ≥ 0.993). While for spermidine, spermine, acetylspermidine, N⁸ -acetylspermidine, and N-acetylspermine, the linearity was good in the range of 0.5-500 μmol/L (R²  ≥ 0.990). The recoveries of three spiked concentrations (0.5, 5, 300 μmol/L) were 85.6%-108.4%, and relative standard deviations for intra- and interday were in the range of 2.9%-13.4% and 4.5%-15.1%, respectively. The method was successfully applied to the analysis of urine samples of gastric cancer patients. The results showed that the levels of most polyamines and N-acetylated polyamines from the patient group were significantly higher than those from the control group. The altered concentrations of the above-mentioned metabolites suggest their role in the pathogenesis of gastric cancer, and they should be further evaluated as potential markers of gastric cancer.

Recent applications and novel strategies for mercury determination in environmental samples using microextraction-based approaches: A review

The growing need to monitor Hg levels in the environment to control its emissions and evaluate the effectiveness of reduction policies is driving the scientific community to focus efforts on creating analytical methods that are simpler, lower cost, more performing, and environmentally sustainable. In this context, an important contribution is provided by microextraction techniques, which have long proven to be simple, reliable, and to ensure an environmentally responsible sample preparation. This manuscript reviews the recent progress in the determination of environmental Hg using microextraction techniques. The considered studies involve all environmental compartments (i.e., air, water, soil, and biota) and have been discussed by grouping them according to the employed technique while pointing out the main advances achieved and the most important limitations. The ultimate goal is to provide an up-to-date overview of the analytical potential of microextraction techniques that can be exploited in various investigation fields and to highlight the most important knowledge gaps that should be addressed in the coming years, such as in-situ sampling, the use of natural materials, and the value of metrological support to obtain data SI-traceable and comparable.

Analytical study on the primary and secondary organic carbon and elemental carbon in the particulate matter at the high-altitude Monte Curcio GAW station, Italy

This study provides a thorough investigation of the trends of organic carbon (OC) and elemental carbon (EC) in particulate matter (PM)₁₀ and PM_2.5 samples collected at the Monte Curcio Observatory (1780 m a.s.l.), a station of the Global Atmosphere Watch (GAW) program and Global Mercury Observation System (GMOS) network. Although the drawn attention toward these pollutants, there is still a lack of data for southern Italy, and this work is a contribution toward the filling of this gap. PM was sampled daily in 2016 and analyzed by thermo-optical transmittance method, while equivalent black carbon (eBC) concentrations in PM₁₀ were simultaneously measured using a multiangle absorption photometer. The results showed that in PM₁₀, the average values of OC and EC were 1.43 μgC/m³ and 0.12 μgC/m³, whereas in PM_2.5, these concentrations were 1.09 μgC/m³ and 0.12 μgC/m³, respectively. We detected a clear seasonal variability in OC and EC with higher concentrations during the warm period. Moreover, the analysis of the OC/EC ratio revealed that most of the carbonaceous aerosol was transported by long-range air masses, as further confirmed by the use of the concentration-weighed trajectory (CWT) model. The mass absorption cross-section at 632 nm of EC (MAC_EC) over the entire period was 9.67 ± 4.86 m²/g and 8.70 ± 3.18 m²/g in PM_2.5 and PM₁₀, respectively, and did not exhibit a clear seasonal variation. The concentrations for OC and EC were also used for the computation of the secondary organic carbon (SOC) content, whose outcomes resulted in a seasonal trend similar to those obtained for OC and EC. As regards the eBC, its weekly pattern showed a slight increase during the weekend in the warm period, consistent with the anthropic activities in the touristic area surrounding the observatory.

An innovative green protocol for the quantification of benzothiazoles, benzotriazoles and benzosulfonamides in PM10 using microwave-assisted extraction coupled with solid-phase microextraction gas chromatography tandem-mass spectrometry

Benzothiazoles (BTHs), benzotriazoles (BTRs), and benzenesulfonamides (BSAs) are chemicals used in several industrial and household applications. Despite these compounds are emerging pollutants, there is still a lack of information about their presence in outdoor air samples. In this paper, we developed a new method for the quantification of BTHs, BTRs, and BSAs in airborne particulate matter (PM₁₀). The extraction of fourteen analytes from PM₁₀ was accomplished by microwave-assisted extraction (MAE) using an environmentally friendly mixture of water and ethanol. SPME was used to analyze the target compounds from the MAE extract by gas chromatography-tandem mass spectrometry (SPME-GC-MS/MS), eliminating additional sample clean-up steps. The best working conditions for MAE and SPME were examined multivariately by experimental design techniques. The target compounds were quantified in selected reaction monitoring acquisition mode. The proposed method was carefully validated, and the achieved results were satisfactory in terms of linearity, lower limit of quantification (picograms per cubic meter), intra- and inter-day accuracy (81-118% and 82-114%, respectively), and precision (repeatability and reproducibility in the range 2.3-17% and 7.4-19%, respectively). The application in a real monitoring campaign showed that the developed protocol is a valuable and eco-friendly alternative to the methods proposed so far.

Polyamines of biological fluids of the body and the diagnostic value of their determination in clinical and laboratory researches (review of literature)

The review provides the analysis of the content of the main polyamines (PA) - spermine, spermidine and putrescine in the most important biological fluids of the human body (blood, urine, seminal fluid, etc.). The assessment of their diagnostic and prognostic value in clinical practice is carried out. The novelty and value of assessing of the level of PA metabolites as new diagnostic markers of various diseases has been shown. Among such diseases as cancer, stroke, renal failure, for which the search for early markers is especially relevant. This survey data can be of practical interest and taken into account in estimating the level of PA and its derivatives in clinical and laboratory reseaches. The literature search for the review was carried out using the Scopus, Web of Science, MedLine, RSCI databases.

Simultaneous determination of methionine cycle metabolites, urea cycle intermediates and polyamines in serum, urine and intestinal tissue by using UHPLC-MS/MS

Metabolites of methionine cycle, urea cycle and polyamine metabolism play important roles in regulating the metabolic processes and the development of diseases. It is rewarding and interesting to monitor the levels of the above metabolites in biological matrices to investigate pathological mechanisms. However, their quantitation is still unsatisfactory due to the poor retention behavior of the analytes on the traditional reversed-phase column. And never a single analytical method simultaneously quantify these three classes of metabolites. Besides, the concentrations of some metabolites are too low to be detected in the biological samples. In this study, we developed a UHPLC-ESI-MS/MS method to simultaneously determine the levels of 14 metabolites, including 4 methionine metabolism metabolites (methionine, homocysteine, S-adenosylmethionine and S-adenosylhomocysteine), 3 urea cycle intermediates (arginine, citrulline and ornithine) and 7 polyamines (putrescine, spermidine, spermine, N¹-acetylputrescine, N¹-acetylspermidine, N¹-acetylspermine and N¹,N¹²-diacetylspermine). The chromatographic separation was performed on the BEH amide column within 14 min using water and acetonitrile (both with 0.1% formic acid) as the mobile phases. The results of method validation showed good selectivity, linearity (r² > 0.99), recovery (93.1%-112.1%), inter-day and intra-day precision (RSD < 13.6% and RSD < 11.0%, respectively), stability (RSD < 15.1%) and matrix effect (76.0%-113.2%). The method is simple, quick and sensitive without derivatization processes and the use of ion-pairing reagents. This approach was successfully applied in urine, serum and tissue matrices, as well as in identifying potential biomarkers for hyperthyroidism and hypothyroidism. The method is promising to provide more information on pathophysiological mechanisms in metabolomics study.

Advances in Solid-Phase Microextraction

Analysis imposes substantial challenges, especially when dealing with analytes present at trace levels in complex matrices [...]

A rapid method for the quantification of urinary phthalate monoesters: A new strategy for the assessment of the exposure to phthalate ester by solid-phase microextraction with gas chromatography and tandem mass spectrometry

In the following work, a new method for the analysis of the phthalate monoesters in human urine was reported. Phthalate monoesters are metabolites generated as a result of phthalate exposure. In compliance with the dictates of Green Analytical Chemistry, a rapid and simple protocol was developed and optimized for the quantification of phthalate monoesters (i.e., monoethyl phthalate, monoisobutyl phthalate, mono-n-butyl phthalate, mono-(2-ethylhexyl) phthalate, mono-n-octyl phthalate, monocyclohexyl phthalate, mono-isononyl phthalate) in human urine, which entails preceding derivatization with methyl chloroformate combined with the use of commercial solid phase microextraction and the analysis by gas chromatography-triple quadrupole mass spectrometry. The affinity of the derivatized analytes toward five commercial coatings was evaluated, and in terms of analyte extraction, the best results were reached with the use of the divinylbenzene/carboxen/polydimethylsiloxane fiber. The multivariate approach of experimental design was used to seek for the best working conditions of the derivatization reaction and the solid phase microextraction, thus obtaining the optimum response values. The proposed method was validated according to the guidelines issued by the Food and Drug Administration achieving satisfactory values in terms of linearity, sensitivity, matrix effect, intra- and inter-day accuracy, and precision.

Recovery of Aromatics from Orange Juice Evaporator Condensate Streams by Reverse Osmosis

The aim of this work was to analyze the potential of reverse osmosis (RO) membranes in the recovery and concentration of aroma compounds from orange juice evaporator condensate (EC) streams. Concentration experiments were performed by using three RO spiral-wound aromatic polyamide membranes (SG1812C-34D, SC1812C-34D and SE1812) with different NaCl rejections. The effect of transmembrane pressure, axial feed flowrate and volume concentration ratio (VCR) on permeate flux was studied. Rejections of the investigated membranes towards specific aroma compounds (octanol, α-terpineol, terpinen-4-ol, cis-carveol, karvon, linalool) in selected operating conditions were also evaluated. The concentrations of the aroma compounds were determined by gas chromatography coupled with mass spectrometry (GC-MS) using headspace solid-phase microextraction (HS-SPME) as a sample preparation approach. For all selected membranes, the permeate flux increased linearly by increasing the operating pressure from 5 to 25 bar; on the other hand, the feed flowrate did not have any significant effect on the permeate flux. High retention values towards aroma compounds (>80%) were measured for all selected membranes. However, the SC membrane showed the highest rejection values (>96%) and the best correlation between concentration factor of aroma compounds and VCR.

Development of a new chromogenic method for putrescine quantification using coupling reactions involving putrescine oxidase

Quantification of polyamines, including putrescine, is generally performed using high-performance liquid chromatography (HPLC) or gas chromatography. However, these methods are time-consuming because of sample derivatization and analytical reagent preparation. In this study, we developed a simple and high-throughput putrescine quantification method on a 96-well microtiter plate using putrescine oxidase from Rhodococcus erythropolis NCIMB 11540, peroxidase, 4-aminoantipyrine, and N-ethyl-N-(3-sulfopropyl)-3-methylaniline sodium salt. The developed method (named as PuO-POD-4AA-TOPS method) was applicable to bacterial culture supernatants. Furthermore, putrescine concentrations determined by the developed method roughly corresponded to the concentrations determined by HPLC.

Recent Applications and Newly Developed Strategies of Solid-Phase Microextraction in Contaminant Analysis: Through the Environment to Humans

The present review aims to describe the recent and most impactful applications in pollutant analysis using solid-phase microextraction (SPME) technology in environmental, food, and bio-clinical analysis. The covered papers were published in the last 5 years (2014–2019) thus providing the reader with information about the current state-of-the-art and the future potential directions of the research in pollutant monitoring using SPME. To this end, we revised the studies focused on the investigation of persistent organic pollutants (POPs), pesticides, and emerging pollutants (EPs) including personal care products (PPCPs), in different environmental, food, and bio-clinical matrices. We especially emphasized the role that SPME is having in contaminant surveys following the path that goes from the environment to humans passing through the food web. Besides, this review covers the last technological developments encompassing the use of novel extraction coatings (e.g., metal-organic frameworks, covalent organic frameworks, PDMS-overcoated fiber), geometries (e.g., Arrow-SPME, multiple monolithic fiber-SPME), approaches (e.g., vacuum and cold fiber SPME), and on-site devices. The applications of SPME hyphenated with ambient mass spectrometry have also been described.

Biogenic Amines Formation Mechanism and Determination Strategies: Future Challenges and Limitations

The evolution in foodstuff-monitoring processes has increased the number of studies on biogenic amines (BAs), in recent years. This trend with future perspective needs to be assembled to address the associated health risks. Thus, this study aims to cover three main aspects of BAs: (i) occurrence, physiology, and toxicological effects, most probable formation mechanisms and factors controlling their growth; (ii) recent advances, strategies for determination, preconcentration steps, model technique, and nature of the matrix; and (iii) milestone, limitations with existing methodologies, future trends, and detailed expected developments for clinical use and on-site ultra-trace determination. The core of the ongoing review will discuss recent trends in pre-concentration toward miniaturization, automation, and possible coupling with electrochemical techniques, surface-enhanced Raman scattering, spectrofluorimetry, and lateral flow protocols to be exploited for the development of rapid, facile, and sensitive on-site determination strategies for BAs.

Selection and application of ssDNA aptamers against spermine based on Capture-SELEX

Spermine contamination ranks as one of the food safety issues, it will cause some adverse reactions if the intake of spermine is excessive in human body. So it is of great significance to establish fast and efficient analysis method to detect spermine in foods. In this study, the spermine aptamers with high affinity and specificity were obtained by the capture systematic evolution of ligands by exponential enrichment (Capture-SELEX) technique. Forty-one aptamer sequences were obtained by cloning and sequencing, and were divided into eight families based on homology and secondary structure analysis. The affinity and specificity of candidate aptamers was analyzed by isothermal titration calorimetry (ITC) and fluorescence assay. The aptamers named APJ-6 was picked out as the optimal aptamer that recognizes spermine specifically with the Kd value of 9.648 ± 0.896 nM. In order to verify the practicability of the selected aptamers, the sensitive aptamer-based fluorescene assay was designed. Under optimized conditions, this aptasensor exhibited a low detection limit of 0.052 nM, as well as a linear within the range of 0.1-20 nM. Besides, it has been further applied for the determination of spermine in pork samples and the recoveries ranged from 86.45% to 98.15%, showing its great potential for sensitive analysis in food safety control.

Improved profiling of polyamines using two-dimensional gas chromatography mass spectrometry

Polyamines are a class of poly-cationic aliphatic amines, playing a role in different cellular processes such as maintaining intracellular pH and membrane potential that are relevant for general cellular physiology and ageing. The development of analytical methods for detection and quantitation of this class of compounds has been challenging due to the basic nature of these species. Both liquid chromatography (LC) and gas chromatography (GC) have been applied for separation, mostly coupled to mass spectrometry (MS) for detection. However, current methodologies suffer from lengthy extraction protocols and limitations in separation and detection levels. Here, we present a simplified and optimised method for straightforward extraction of polyamine metabolites including spermine, spermidine, norspermidine, cadaverine and putrescine from cellular and tissue material. We demonstrate that strong acid-based extraction and chemical derivatisation not only improves isolation, but also recovery. Combined with two-dimensional gas chromatography, this method provides clear separation and femtomole sensitivity for the profiling of polyamines.

Electrophoretic analysis of polyamines in exhaled breath condensate based on gold-nanoparticles microextraction coupled with field-amplified sample stacking

In this work, citrate-capped gold-nanoparticles (citrate-AuNPs) have been firstly used for selective extraction of trace polyamines, putrescine (Put) and cadaverine (Cad), followed by field-amplified sample stacking (FASS) coupled with capillary electrophoresis and capacitively coupled contactless conductivity detection (FASS-CE-C⁴D). Put and Cad were extracted by electrostatic attractions between the amine group of the polyamines and the citrate ligands adsorbed on the surfaces of AuNPs. AuNPs microextraction (AuNPs-ME) effectively shortened preparation time (50 min) by introducing ultrasound, and the required sample extraction volume was only 1 mL. Furthermore, a synergistic enrichment strategy based on off-line AuNPs-ME and on-line FASS significantly improved the detection sensitivity, making the enrichment factors up to 1726-1887 times. Under the optimum conditions, Put and Cad could be well separated from the potential coexisting substances and then directly determined by CE-C⁴D without derivatization. Due to its low sample consumption, high sensitivity (LODs: 0.070-0.17 ng mL^-1), and acceptable recoveries (90-105%), this AuNPs-ME/FASS-CE-C⁴D method provides a rapid, economical and eco-friendly approach for direct determination of polyamines in human exhaled breath condensate, and has potential application prospects in preliminary noninvasive diagnosis of oral and respiratory inflammation.