Determination of 2-butoxyethanol and butoxyacetic acid in rat and human blood by gas chromatography-mass spectrometry

Determination of urinary metabolites of alkyl cellosolves by solid phase extraction and GC/FID

Alkyl cellosolves include ethylene glycol monomethylether, ethylene glycol monoethylether, ethylene glycol monobuthylether. And their urine metabolites are methoxyacetic acid, ethoxyacetic acid and butoxyacetic acid. The current analytical method for urinary alkoxyacetic acid is liquid-liquid phase extraction. But the liquid-liquid phase extraction method needs a more complex pre-treatment process and has a low recovery rate. We determined the appropriate extraction solvent and its flow rate. We also evaluated the non-absorptive rate and recovery rate according to particle size. Finally we developed a convenient solid phase extraction method for the analysis of urine cellosolve metabolites. As a result, the recovery rates for methoxyacetic acid, ethoxyacetic acid and butoxyacetic acid were 100.4 +/- 1.6%, 100.2 +/- 1.8% and 100.7 +/- 10.0% respectively, when acetone was used as the extraction solution. The most appropriate flow rate was 0.1 ml/min. At a particle size of 140-200 mesh, non-absorption percentages for methoxyacetic acid, ethoxyacetic acid, butoxyacetic acid were 3.2 +/- 0.3%, 1.0 +/- 0.1% and 1.1 +/- 0.1%, and the recovery rates according to particle size were similar. Further evaluation of the recovery rate and non-absorptive rate according to the mini column shape, stationary phase and recovery rate with various extracting solutions is required.

Synthesis, characterization, and use of 2-[(2H(9))butoxy]acetic acid and 2-(3-methylbutoxy)acetic acid as an internal standard and an instrument performance surrogate, respectively, for the gas chromatographic-mass spectrometric determination of 2-butoxyacetic acid, a human metabolite of 2-butoxyethanol

2-[(2H(9))Butoxy]acetic acid and 2-(3-methylbutoxy)acetic acid were synthesized, mixed with 2-butoxyacetic acid, and separated by capillary gas chromatography on a fused-silica column with a length of 50 m, inside diameter of 0.200 mm, and a "free fatty acid phase" wall coating of 0.3 microm film. 2-[(2H(9))Butoxy]acetic acid, 2-butoxyacetic acid, and 2-(3-methylbutoxy)acetic acid were baseline resolved at retention times of 13.55, 13.78, and 15.20 min; 2-(3-methylbutoxy)acetic acid having a peak efficiency of 360,000. Mass spectrometric detection using selected ion monitoring at m/z 66, 57, and 71 showed linear analytical responses from 0.04 ng to at least 200 ng with a limit of detection of 0.04 ng for 2-butoxyacetic acid.

Repeated ingestion of 2-butoxyethanol: case report and literature review

BACKGROUND

Ethylene glycol monobutyl ether (2-butoxyethanol) is not commonly associated with significant human poisoning. Exposures are usually through occupational contact and typically involve inhalation injury. Animal studies report severe hemolysis occurring in rats and mice. Rare published human cases give varied descriptions of the clinical course associated with 2-butoxyethanol poisoning including reports of metabolic acidosis, ethylene glycol production, oxaluria, renal failure, and anemia. We report a case of two separate ingestions (80 to 100 grams) of a glass cleaner concentrate containing 22% 2-butoxyethanol, and its primary metabolite butoxyacetic acid.

CASE REPORT

An 18-year-old male ingested 360-480 mL of 22% 2-butoxyethanol on two separate occasions. Approximately 10hours after the first ingestion, the patient developed severe CNS depression, metabolic acidosis, hematuria, and mild elevation of hepatic enzymes. He was treated initially with ethanol therapy but continued to deteriorate and was started on hemodialysis. Approximately 10 days after discharge, the patient ingested 480 mL of the same product and received ethanol and hemodialysis within four hours of ingestion. During his second admission the patient did not develop the delayed severe CNS depression or profound metabolic acidosis. Clinically significant hemolytic anemia, oxaluria, ethylene glycol production, and renal failure were not noted in either episode. The patient recovered on both occasions without sequelae.

CONCLUSION

Hemodialysis may be an effective treatment intervention for managing severe acute 2-butoxyethanol intoxication, however, further investigation is warranted.

Optimization of the headspace solid-phase microextraction for determination of glycol ethers by orthogonal array designs

A headspace solid-phase microextraction (HS-SPME), in conjunction with gas chromatography-flame ionization detection for use in the determination of six frequently used glycol ethers at the microg/l level is described. A 75 microm Carboxenpolydimethylsiloxane fiber was used to extract the analytes from an aqueous solution. Experimental HS-SPME parameters such as extraction temperature, extraction time, salt concentration and sample volume, were investigated and optimized by orthogonal array experimental designs. The relative standard deviations for the reproducibility of the optimized HS-SPME method varied from 1.48 to 7.59%. The correlation coefficients of the calibration curves exceeded 0.998 in the microg/l range of concentration with at least two orders of magnitude. The method detection limits for glycol ethers in deionized water were in the range of 0.26 to 3.42 microg/l. The optimized method was also applied to the analysis of glycol ethers in urine and blood samples with the method detection limits ranged from 1.74 to 23.2 microg/l.

Determination of estrogens in river water by gas chromatography-negative-ion chemical-ionization mass spectrometry

A method for the determination of estrogens (17alpha-estradiol, 17beta-estradiol, estrone, ethynyl estradiol, and estriol) as pentafluorobenzyl-trimethylsilyl (PFB-TMS) derivatives by gas chromatography-mass spectrometry (GC-MS) with negative-ion chemical-ionization (NICI) is described. The NICI of all the derivatives produced an intense [M-PFB]- ion as the base peak. The reagent gas (methane) flow-rate and the ion source temperature were determined to be 2.0 ml/min and 240 degrees C, respectively, for the optimized NICI-selected ion monitoring (SIM) conditions. The sensitivities of the PFB-TMS derivatives in the NICI mode were 8.0-130 times higher than those of the PFB-TMS derivatives in electron ionization (EI) mode, and 12-25 times higher than those of all the TMS derivatives in the EI mode. This method was applied to the analysis of estrogens in river water using a solid-phase extraction as the sample preparation. The recoveries of the target chemicals from a river-water sample spiked with standards at 2 ng/l level were 85.8-126.5% (RSD, 6.2-13.0%). The methodical detection limits ranged from 0.10 to 0.28 ng/l.

Butoxyethanol ingestion with prolonged hyperchloremic metabolic acidosis treated with ethanol therapy

BACKGROUND

Severe toxic ingestions of butoxyethanol (CAS No. 111-76-2) are rare despite the prevalence of this glycol ether in products such as glass and surface cleaners. Manifestations of acute butoxyethanol toxicity include metabolic acidosis, hemolysis, hepatorenal dysfunction, and coma, but vary widely in reported cases. Furthermore, the optimal therapeutic approach is not yet established. Much of the toxicity of butoxyethanol has been ascribed to its aldehyde and acid metabolites which are similar to those produced by oxidative metabolism of methanol and ethylene glycol. Although the roles of alcohol dehydrogenase inhibition with ethanol or fomepizole and hemodialysis are clear in the case of toxic ingestions of methanol and ethylene glycol, they remain poorly defined for butoxyethanol poisoning.

CASE REPORT

We report the case of a 51-year-old female who ingested up to 8 ounces of Sanford Expo White Board Cleaner (butoxyethanol and isopropanol). She developed prolonged hyperchloremic metabolic acidosis and mental status depression and was treated with ethanol therapy but not hemodialysis. This patient recovered without apparent sequelae. The kinetics of butoxyethanol metabolism in this case are described and the potential therapeutic options are discussed.

Improved method to measure urinary alkoxyacetic acids

OBJECTIVES

To simplify the current preparation of samples, and to improve the specificity and reliability of the conventional analytical methods to measure urinary alkoxyacetic acids.

METHODS

Samples containing alkoxyacetic acids including methoxy, ethoxy, and butoxyacetic acids (MAA, EAA, and BAA) were acidified with HCl and extracted with a mixed solvent of methylene chloride and isopropyl alcohol, then analysed by gas chromatography/mass spectrometry (GC/MS).

RESULTS

Optimal results were obtained when pH was 1.05-1.45, the ratio of methylene chloride and isopropyl alcohol was 2:1, and when extraction time was 10 minutes. Over the concentration range 0.3-200 micrograms/ml, MAA, EAA, and BAA could be determined with a pooled coefficient of variation (nine concentrations, six replicate samples) of 5.55%, 6.37%, and 6.41%, respectively. Urine samples were stable for at least 5 months and 3 freeze-thaw cycles at -20 degrees C. The limits of detection of MAA, EAA, and BAA were 0.055, 0.183, and 0.009 microgram/ml, respectively. The matrix effect of urine samples was negligible for MAA and EAA, but were marginally significant for BAA. The average recoveries of alkoxyacetic acids were 99%-101%. In urine samples MAA from 15 exposed workers showed a strong linear correlation (r = 0.999, slope = 1.01) between the new GC/MS method and Sakai's GC method.

CONCLUSIONS

The simplified non-derivatisation pretreatment of samples coupled with GC/MS can provide a specific, sensitive, simple, safe, and reliable method for the biological monitoring of occupational exposure of ethylene glycol ethers.