Direct methyl esterification with 2,2-dimethoxypropane for the simultaneous determination of urinary metabolites of toluene, xylene, styrene, and ethylbenzene by gas chromatography-mass spectrometry

Abstract

Objectives The purpose of this study was to develop a simple and accurate gas chromatography‐mass spectrometry (GC‐MS) method for simultaneous determination of four urinary metabolites from four organic solvents, that is, hippuric acid (HA) from toluene, methylhippuric acid (MHA) from xylene, and mandelic acid (MA) and phenylglyoxylic acid (PGA) from styrene or ethylbenzene for biological monitoring. Methods The four metabolites were directly methyl‐esterified with 2,2‐dimethoxypropane and analyzed using GC‐MS. The proposed method was validated according to the US Food and Drug Administration guidance. The accuracy of the proposed method was confirmed by analyzing a ClinChek ® —Control for occupational medicine (RECIPE Chemicals +Instruments GmbH). Results Calibration curves showed linearity in the concentration range of 10‐1000 mg/L for each metabolite, with correlation coefficients >0.999. For each metabolite, the limits of detection and quantification were 3 mg/L and 10 mg/L, respectively. The recovery was 93%‐117%, intraday accuracy, expressed as the deviation from the nominal value, was 92.7%‐103.0%, and intraday precision, expressed as the relative standard deviation (RSD), was 1.3%‐4.7%. Interday accuracy and precision were 93.4%‐104.0% and 1.2%‐9.5%, respectively. The analytical values of ClinChek obtained using the proposed method were sufficiently accurate. Conclusions The proposed method is a simple and accurate which is suitable for routine analyses that could be used for biological monitoring of occupational exposure to four organic solvents.

Liquid phase microextraction techniques combined with chromatography analysis: a review

“…Recently, Takeuchi et al proposed the 2,2-dimethoxy-propane (DMP) as a derivatizing agent to determine organic acids: DMP acted as dehydration and derivatization reagent; in the presence of HCl, the organic acids were directly methylated with DMP and can be analyzed by GC-MS. The advantages of using DMP are that extraction and evaporation procedure are not needed [139].…”

Luminescent sensors based on coordination polymers with adjustable emissions for detecting biomarker of pollutant ethylbenzene and styrene

“…As displayed in Table S1, LCP 1 crystallizes in the trigonal R-3 space group, and the asymmetric unit consists of one crystallographically independent Nd 3+ ion, three TCPB 3− ligands, and three coordinated DMF molecules (Figure 1a). Each Nd 3+ ion is bonded to six oxygen atoms from TCPB 3− ligands (O 1 , O 2 , O 4 , O 6 , O 7 , and O 9 ) and three oxygen atoms from coordinated DMF molecules (O 3 , O 5 , and O 8 ) with Nd O bond distances of 2.357(2)-2.535(2) (4) Å and bond angle O Nd O of 52.63(7)-148.23 (9) (Table S2), consistent with the normal range reported in the literature. [19] In the crystal lattice, Nd 3+ ion displays a tricapped trigonal prism geometry (Figure 1b), and the neighboring ninecoordinated Nd 3+ ions are bridged via the carboxylate groups of TCPB 3− ligand, forming the 2D layer coordination network (Figure 1c).…”

“…[ 7 ] The strong correlation between the exposure level of EB/S and quantity of urinary PGA excreted has also been reported in occupational environments. [ 6,7 ] Currently, the analytical methods developed for PGA analysis (capillary electrophoresis, [ 8 ] gas chromatography–mass spectrometry, [ 9 ] and liquid chromatography–mass spectrometry [ 10 ] ) have some limitations of complex sample processing, lack of portability, high costs, and time‐consuming procedures. Luminescence technique is highly preferred for chemical sensing and affords potential advantages of quick response, high sensitivity and selectivity, and cost efficiency.…”

Ultrastable Tb-Organic Framework as a Selective Sensor of Phenylglyoxylic Acid in Urine

“…A variety of detection methods for PGA have been reported, including high-performance liquid chromatography–mass spectrometry (HPLC–MS), , gas chromatography–mass spectrometry, reagent-free ion chromatography, voltammetry, and multipumping flow systems . Nevertheless, these precise measurement techniques often face the shortcomings of expensive equipment, tedious sample pretreatment, possible toxic chemical exposure, and considerable time consumption …”