A simple and effective general test method for 2-butoxyacetic acid (2-BAA) in urine samples was developed. 2-Butoxyacetic acid is a metabolite and biomarker for exposure to 2-butoxyethanol (2-BE), a glycol ether and is of concern because of the general toxicity of this class of compounds. Glycol ethers have been frequently reported to damage the male reproductive system, hematopietic system, and fetal/embryonic development. Occupational exposure by these widely used glycol ethers is likely, since they are readily absorbed through the skin. Specifically, 2-BE is used as a component in paints, inks and common house hold cleaning products, and is of interest to this laboratory for exposed populations. For the use of this test on urine, specimens were first spiked with deuterated 2-BAA; the deuterated analog was used as a procedural internal standard. The samples were extracted with ethyl acetate, concentrated, and treated by acid catalyzed esterification to produce the corresponding ethyl esters of 2-BAA. Subsequently, the ethyl ester derivatives were extracted using methylene chloride and concentrated to produce the final solution for gas chromatographic analysis. A mass selective detector (MSD) using a 50-m X 0.20-mm (id) HP-1 capillary column and a temperature program of 60 to 150oC was used for the gas chromatographic measurement. Ion m/z 57 was monitored for the ethyl ester of 2-BAA and ion m/z 66 was monitored for the internal standard. A series of recovery studies using 1, 5, 10 and 20 µg/ml 2-BAA spiked urine samples demonstrated good accuracy and precision; recovery varied between 100-102% of theory. The limit of detection (LOD) was found to range from 0.005 to 0.015 µg/ml for this analysis method.
The Toxicologist. Society of Toxicology 46th Annual Meeting and ToxExpo, March 25-29, 2007, Charlotte, North Carolina