A comparison and evaluation of analysis procedures for the quantification of (2-methoxyethoxy)acetic acid in urine

Several extraction and derivatization procedures were evaluated for the quantification of (2-methoxyethoxy) acetic acid (MEAA) in urine. MEAA is a metabolite and a biomarker for exposure to 2-(2-methoxyethoxy)ethanol, a glycol ether with widespread use in various industrial applications and the specific use as an anti-icing additive in the military jet fuel formulation JP-8. Quantification of glycol ether biomarkers is an active area Of Current analytical research. Various sample preparation procedures were evaluated; liquid-liquid extraction (LLE) using ethyl acetate yielded the highest recovery, and solid-phase extraction (SPE) gave low recovery of MEAA. Two derivatization procedures were thoroughly investigated and validated. Silylation of MEAA with N-methyl-N-[tert-butyldimethylsilyl]trifluoroacetamide (MTBSTFA) was one approach, and esterification of MEAA using ethanol was the other. Quantification was by means of a gas chromatograph (GC) equipped with a mass spectrometer for a detector and using a polydimethylsiloxane (HP-1) capillary column. Deuterated 2-butoxyacetic acid (d-BAA) was used as an internal standard. Recovery studies of spiked human urine demonstrated the accuracy and precision for both procedures. The limit of detection (LOD) and other figures of merit for both derivatization procedures will be discussed in detail. Applications of these analysis procedures are also discussed.