A fast and simple solid phase microextraction coupled with gas chromatography-triple quadrupole mass spectrometry method for the assay of urinary markers of glutaric acidemias

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.

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.

Development and Application of Green or Sustainable Strategies in Analytical Chemistry

Analytical chemistry is bound to face growing challenges in the near future, especially for the quantification of trace analytes in complex matrices [...]

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.

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.

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.

Microwave-assisted synthesis of porphyrin conjugated microporous polymers for microextraction of volatile organic acids in tobaccos

Conjugated microporous polymers (CMPs) with permanent microporosity and extended p-conjugated skeletons have recently shown the fascinating application in separation and enrichment. In this report, porphyrin CMP that possessed microporous structure and nitrogen-rich pyrrole building blocks was successfully synthesized by microwave-assisted method. Then, a novel coating based on porphyrin CMP was fabricated on silica fiber for efficient enrichment volatile organic acids (VOAs). The simulation showed the coating exhibited strong interaction with volatile organic acids based on charge transfer interaction, hydrogen bond and size effect. Hence, we proposed a method for determination of volatile organic acids in tobaccos by headspace solid-phase microextraction (HS-SPME) with porphyrin CMP coating by gas chromatography-mass spectrometry. The results showed that the coating provided high enrichment factors for VOAs ranging from 66,657 to 133,970 and low limits of detection from 4.6 to 22 ng/L. A good linearity was observed for propionic acid and crotonic acid ranging from 0.050 to 8.0 μg/L, 2-methylheptanoic acid ranging from 0.063 to 1.5 μg/L, others ranging from 0.025 to 3.0 μg/L with the determination coefficient (R2) between 0.9900 and 0.9980. The strategy for determination of volatile compounds in complex solid samples was successfully applied to the analysis of volatile organic acids in tobacco leaves. The results showed that the method was accurate and reliable.

A targeted metabolomic protocol for quantitative analysis of volatile organic compounds in urine of children with celiac disease

Volatile organic compounds (VOCs) in biological samples have gained popularity for disease monitoring and diagnosis. Celiac disease (CD) is one of the many prevalent health conditions which are challenging to diagnose. The aim of this study was to optimize a solid phase microextraction followed by gas chromatography-mass spectrometry, for quantitative analysis of a wide range of VOCs in the urine of patients with CD. Multivariate design of experiment was used to optimize the extraction conditions for the analysis of 15 urinary VOCs. Based on the performed experiments, extraction using 2.98 g of sodium chloride and 21 μL of 6 M hydrochloric acid for 15 min at 30 °C, using a CAR/PDMS fiber in headspace mode was found to be the most effective procedure for the analysis of the selected biomarkers. It was also demonstrated that the proposed method could distinguish between children with CD and healthy children based on the profile of VOCs. It is believed that quantitative analysis of these biomarkers will extend our understanding of CD and could be used for monitoring in patients under treatment.

Quantitation of plasma and urine 3-hydroxyglutaric acid, after separation from 2-hydroxyglutaric acid and other compounds of similar ion transition, by liquid chromatography-tandem mass spectrometry for the confirmation of glutaric aciduria type 1

BACKGROUND

Glutaric aciduria type 1, a deficiency of glutaryl-CoA dehydrogenase, causes an accumulation of neurotoxic metabolites glutaric acid and 3-hydroxyglutaric acid (3-HGA). Testing of these analytes is routinely done by GC-MS but seldom account for interference from isomers or compounds with similar ion transitions. We developed a liquid chromatography tandem mass spectrometry method that accurately measures 3-HGA in urine and plasma specimens, while utilizing similar reagents and instrumentation used for the routine performance of amino acid and acylcarnitine analysis in determining the diagnosis of several metabolic disorders.

METHOD

Plasma and urine samples were added aliquots of the deuterated 3-HGA internal standard and acetonitrile. The protein-free supernatant was brought to dryness, and the residue derivatized using 3 M HCL in 1-butanol with heating. The dried derivative was then reconstituted in 50% methanol-water solution and aliquot transferred to an HPLC vial for analysis by LC-MS/MS. Separation was performed using a C8 HPLC column under flow gradient conditions of 0.2% formic acid in water and methanol, respectively. Ionization was by ESI and detection of selected precursor-product ion transitions by multiple reaction monitoring (MRM) in positive mode.

RESULTS

The butyl-ester derivative of 3-HGA eluted at 7.82 min while 2-hydroxyglutaric acid (2-HGA) eluted at 8.21 min. This was equivalent to a separation factor of 1.05 and a resolution of 1.03, respectively. The 3-HGA calibration curve was linear over the range 6.20-319 ng mL^-1 (r² = 0.9996), and the reportable range determined by the linearity was found to be 1.54-384 ng mL^-1. The calculated limits of detection and quantitation were 0.348 and 1.56 ng mL^-1, respectively. Intra- and Inter-assay %CVs for quality control plasma and urine samples ranged from 2 to 18%, with recoveries of 66-115%. The method correlated to the gold standard GC-MS method for both serum (r² ≥ 0.996) and urine analysis (r² ≥ 0.949). The concentration of 3-HGA in normal, non-GA1 individuals was ≤25.2 ng mL^-1 (in plasma) and ≤ 35.0 μmol mmol^-1 of creatinine (in urine).

CONCLUSIONS

This LC-MS/MS method accurately quantified plasma and urine 3-HGA concentration after successful resolution from 2-HGA and other compounds with similar ion transitions. This method is suitable for confirmatory testing of 3-HGA, as a follow-up to an abnormal newborn screen test result, with concern for GA type 1.