Aqueous phase hexylchloroformate derivatization and solid phase microextraction: Determination of benzoylecgonine in urine by gas chromatography-quadrupole ion trap mass spectrometry

Brad J. Hall, Aashish R. Parikh, Jennifer S. Brodbelt

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

A derivatization/solid phase microextraction (SPME) method for the determination of benzoylecgonine in urine was developed. The derivatization is conducted directly in 1 mL of urine while sonicating for 3 min with 12 μL of hexyl chloroformate and 70 μL of a mixture containing acetonitrile:water:hexanol:2-dimethylaminopyridine (5:2:2:1 v/v), yielding benzoylecgonine hexyl ester (BHE) as the product. After the 3 min period, an aliquot of 250 μL is transferred to a vial for SPME. After the desired extraction time the 100 μm polydimethylsiloxane SPME fiber was transferred to the GC-MS for separation and analysis with a quadrupole ion trap mass spectrometer. The hexyl chloroformate derivatization and SPME procedures were optimized for compatibility and sensitivity. The method was found linear for 0.10 to 20.0 μg/mL (r2 = 0.999) of benzoylecgonine in urine using benzoylecgonine-d3 as an internal standard (1.5 μg/mL). Intra-day precisions were 8.8 and 6.8% RSD for 0.30 μg/mL and 17 μg/mL benzoylecgonine standards in urine (n = 6), respectively. Inter-day precision (n = 3) were ≤3.3% RSD, indicating good reproducibility. A detection limit of 0.03 μg/mL (S/N = 3) was achieved, thus making the SPME method a simplified alternative to SPE for GC-MS confirmation after EMIT tests for benzoylecgonine which have a cutoff of 0.30 μg/mL. Quantitative results by SPME and SPE of two clinical urine specimens known positive for cocaine by EMIT were in excellent agreement. Benzoylecgonine was detected by the derivatization/SPME method in 22 out of 22 other urine specimens known positive for cocaine.

Original languageEnglish (US)
Pages (from-to)527-534
Number of pages8
JournalJournal of Forensic Sciences
Volume44
Issue number3
StatePublished - May 1999

Fingerprint

Solid Phase Microextraction
Gas Chromatography
Mass Spectrometry
Urine
Ions
Cocaine
water
hexylchloroformate
benzoylecgonine
Limit of Detection
Esters
Water

Keywords

  • Benzoylecgonine
  • Chloroformate derivatization
  • Cocaine metabolite
  • Forensic science
  • Forensic toxicology
  • Gas chromatography-mass spectrometry
  • Hexyl chloroformate
  • Solid phase microextraction (SPME)

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Law

Cite this

@article{38209d52eddf4f268ed04293ef3b3ccb,
title = "Aqueous phase hexylchloroformate derivatization and solid phase microextraction: Determination of benzoylecgonine in urine by gas chromatography-quadrupole ion trap mass spectrometry",
abstract = "A derivatization/solid phase microextraction (SPME) method for the determination of benzoylecgonine in urine was developed. The derivatization is conducted directly in 1 mL of urine while sonicating for 3 min with 12 μL of hexyl chloroformate and 70 μL of a mixture containing acetonitrile:water:hexanol:2-dimethylaminopyridine (5:2:2:1 v/v), yielding benzoylecgonine hexyl ester (BHE) as the product. After the 3 min period, an aliquot of 250 μL is transferred to a vial for SPME. After the desired extraction time the 100 μm polydimethylsiloxane SPME fiber was transferred to the GC-MS for separation and analysis with a quadrupole ion trap mass spectrometer. The hexyl chloroformate derivatization and SPME procedures were optimized for compatibility and sensitivity. The method was found linear for 0.10 to 20.0 μg/mL (r2 = 0.999) of benzoylecgonine in urine using benzoylecgonine-d3 as an internal standard (1.5 μg/mL). Intra-day precisions were 8.8 and 6.8{\%} RSD for 0.30 μg/mL and 17 μg/mL benzoylecgonine standards in urine (n = 6), respectively. Inter-day precision (n = 3) were ≤3.3{\%} RSD, indicating good reproducibility. A detection limit of 0.03 μg/mL (S/N = 3) was achieved, thus making the SPME method a simplified alternative to SPE for GC-MS confirmation after EMIT tests for benzoylecgonine which have a cutoff of 0.30 μg/mL. Quantitative results by SPME and SPE of two clinical urine specimens known positive for cocaine by EMIT were in excellent agreement. Benzoylecgonine was detected by the derivatization/SPME method in 22 out of 22 other urine specimens known positive for cocaine.",
keywords = "Benzoylecgonine, Chloroformate derivatization, Cocaine metabolite, Forensic science, Forensic toxicology, Gas chromatography-mass spectrometry, Hexyl chloroformate, Solid phase microextraction (SPME)",
author = "Hall, {Brad J.} and Parikh, {Aashish R.} and Brodbelt, {Jennifer S.}",
year = "1999",
month = "5",
language = "English (US)",
volume = "44",
pages = "527--534",
journal = "Journal of Forensic Sciences",
issn = "0022-1198",
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T1 - Aqueous phase hexylchloroformate derivatization and solid phase microextraction

T2 - Determination of benzoylecgonine in urine by gas chromatography-quadrupole ion trap mass spectrometry

AU - Hall, Brad J.

AU - Parikh, Aashish R.

AU - Brodbelt, Jennifer S.

PY - 1999/5

Y1 - 1999/5

N2 - A derivatization/solid phase microextraction (SPME) method for the determination of benzoylecgonine in urine was developed. The derivatization is conducted directly in 1 mL of urine while sonicating for 3 min with 12 μL of hexyl chloroformate and 70 μL of a mixture containing acetonitrile:water:hexanol:2-dimethylaminopyridine (5:2:2:1 v/v), yielding benzoylecgonine hexyl ester (BHE) as the product. After the 3 min period, an aliquot of 250 μL is transferred to a vial for SPME. After the desired extraction time the 100 μm polydimethylsiloxane SPME fiber was transferred to the GC-MS for separation and analysis with a quadrupole ion trap mass spectrometer. The hexyl chloroformate derivatization and SPME procedures were optimized for compatibility and sensitivity. The method was found linear for 0.10 to 20.0 μg/mL (r2 = 0.999) of benzoylecgonine in urine using benzoylecgonine-d3 as an internal standard (1.5 μg/mL). Intra-day precisions were 8.8 and 6.8% RSD for 0.30 μg/mL and 17 μg/mL benzoylecgonine standards in urine (n = 6), respectively. Inter-day precision (n = 3) were ≤3.3% RSD, indicating good reproducibility. A detection limit of 0.03 μg/mL (S/N = 3) was achieved, thus making the SPME method a simplified alternative to SPE for GC-MS confirmation after EMIT tests for benzoylecgonine which have a cutoff of 0.30 μg/mL. Quantitative results by SPME and SPE of two clinical urine specimens known positive for cocaine by EMIT were in excellent agreement. Benzoylecgonine was detected by the derivatization/SPME method in 22 out of 22 other urine specimens known positive for cocaine.

AB - A derivatization/solid phase microextraction (SPME) method for the determination of benzoylecgonine in urine was developed. The derivatization is conducted directly in 1 mL of urine while sonicating for 3 min with 12 μL of hexyl chloroformate and 70 μL of a mixture containing acetonitrile:water:hexanol:2-dimethylaminopyridine (5:2:2:1 v/v), yielding benzoylecgonine hexyl ester (BHE) as the product. After the 3 min period, an aliquot of 250 μL is transferred to a vial for SPME. After the desired extraction time the 100 μm polydimethylsiloxane SPME fiber was transferred to the GC-MS for separation and analysis with a quadrupole ion trap mass spectrometer. The hexyl chloroformate derivatization and SPME procedures were optimized for compatibility and sensitivity. The method was found linear for 0.10 to 20.0 μg/mL (r2 = 0.999) of benzoylecgonine in urine using benzoylecgonine-d3 as an internal standard (1.5 μg/mL). Intra-day precisions were 8.8 and 6.8% RSD for 0.30 μg/mL and 17 μg/mL benzoylecgonine standards in urine (n = 6), respectively. Inter-day precision (n = 3) were ≤3.3% RSD, indicating good reproducibility. A detection limit of 0.03 μg/mL (S/N = 3) was achieved, thus making the SPME method a simplified alternative to SPE for GC-MS confirmation after EMIT tests for benzoylecgonine which have a cutoff of 0.30 μg/mL. Quantitative results by SPME and SPE of two clinical urine specimens known positive for cocaine by EMIT were in excellent agreement. Benzoylecgonine was detected by the derivatization/SPME method in 22 out of 22 other urine specimens known positive for cocaine.

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KW - Cocaine metabolite

KW - Forensic science

KW - Forensic toxicology

KW - Gas chromatography-mass spectrometry

KW - Hexyl chloroformate

KW - Solid phase microextraction (SPME)

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