Determination of methylmalonic acid and glutaric acid in urine by aqueous‐phase derivatization followed by headspace solid‐phase microextraction and gas chromatography‐mass spectrometry

Abstract

In this work, a novel technique of aqueous-phase derivatization followed by headspace solid-phase microextraction and gas chromatography-mass spectrometry was developed for the determination of organic acids in urine. The analytical procedure involves derivatization of organic acids to their ethyl esters with diethyl sulfate, headspace sampling, and GC/MS analysis. The proposed method was applied to the determination of methylmalonic acid and glutaric acid in urine. The experimental parameters and method validation were studied. Optimal conditions were obtained: PDMS fiber, extraction temperature 55 degrees C, extraction time 30 min, and 60 microL of diethyl sulfate as derivatization reagent with 2 mg of the ion pairing agent tetrabutylammonium hydrogensulfate. The method was linear over three orders of magnitude, and detection limits were 21 nM for methylmalonic acid and 34 nM for glutaric acid, respectively. Consequently, in-situ derivatization/HS-SPME/GC/MS is an alternative and powerful method for determination of organic acids as biomarkers in biological fluids.

Determination of organic acids in urine by solid‐phase microextraction and gas chromatography–ion trap tandem mass spectrometry previous ‘in sample’ derivatization with trimethyloxonium tetrafluoroborate

“…The choice of crown ethers as a support compound for the reaction, reported by some authors (Knapp, 1979;Davis, 1977;Neu et al, 1991), is very expensive and in the presence of moisture produces artifacts. Another possibility for 'in-matrix' derivatization of organic acid is represented by alkylation with dimethyl sulfate or diethyl sulfate (Diaz et al, 2006;Li et al, 2007) to the corresponding methylester. The addition of modifiers, such as ion-pairing agents which activate the analytes during derivatization in the injection port, increases esterification yields (Nietzel et al, 1998;Sarriòn et al, 2000;Li et al, 2007).…”

“…Another possibility for 'in-matrix' derivatization of organic acid is represented by alkylation with dimethyl sulfate or diethyl sulfate (Diaz et al, 2006;Li et al, 2007) to the corresponding methylester. The addition of modifiers, such as ion-pairing agents which activate the analytes during derivatization in the injection port, increases esterification yields (Nietzel et al, 1998;Sarriòn et al, 2000;Li et al, 2007). Quaternary ammonium salts, tetramethylammonium hydroxide and tetramethylammonium hydrogen sulfate were employed to convert C 14 -C 22 fatty acid (Pan and Pawliszyn, 1997), but the effect of the injector temperature on the efficiency of derivatization was a critical factor.…”

Development of microwave-assisted headspace solid-phase microextraction followed by gas chromatography-mass spectrometry for the analysis of phenol in a cigarette pad

“…In our previous studies, SPME processes followed by GC-MS have been developed for the analyses of essential oils and biomarkers such as acetone in blood. [21][22][23][24][25][26][27][28] It has been demonstrated in the previous work that microwave irradiation can improve the HS-SPME extraction efficiency and shorten the extraction time. For example, microwave-assisted HS-SPME has been successfully applied to the analysis of volatile compounds in traditional Chinese medicines.…”

An ultrastable zinc-based organic framework as a recyclable luminescent probe for methylmalonic acid detection

“…64 Sensing properties toward MMA MMA serves as a typical biomarker for vitamin B 12 deficiency, and its concentration in the serum and urine can reflect the degree of cobalamin transport and metabolism disorders in humans. [65][66][67] To verify the sensing potential of compound 1 in the serum system toward MMA, the luminescence response toward major constituents (1 mg mL À1 , 500 mL) in serum including glucose, NaCl, KCl, MgCl 2 , CaCl 2 , urea, NaHCO 3 , L-pro and their mixture was investigated, respectively. Interestingly, the emission intensity relies on the identities of serum components: obvious luminescence quenching of compound 1 was observed with the addition of MMA into 1-H 2 O, while other substances had a negligible effect on the luminescence of compound 1 (Fig.…”