Analysis of Urinary Benzodiazepines Using Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry

Abstract

A solid-phase extraction and GC-MS confirmation method was developed for certain urinary diazolo- and triazolobenzodiazepines, including the metabolites of lorazepam, clonazepam, alprazolam, and triazolam. The latter two do not form benzophenones, and the others are not readily confirmed by conventional thin-layer chromatography or GC-MS techniques. Samples were hydrolyzed with glucuronidase at 37 degrees C, adjusted to pH 4.5, extracted with Bond Elut Certify columns, dried, and derivatized using BSTFA with 1% TMCS. Sample preparation time averaged 4 hours. A GC-MS selected-ion-monitoring acquisition method targeting retention time, molecular ion abundances, and qualifier ion ratios was used to determine positive results. The recovery of 7-NH2-clonazepam was 95%, and recoveries of alpha-hydroxyalprazolam, alpha-hydroxytriazolam, and lorazepam were greater than 66%. Linearity was demonstrated from 0.1 to 1.0 microgram/mL for each drug. Within-run CVs were less than 11%, and between-run CVs were less than 16%. Using this technique, we have been able to confirm suspected cases of abuse that had not been confirmed by previous techniques.

Extraction and analysis of clonazepam and 7-aminoclonazepam in whole blood using a dual internal standard methodology

“…Instrumental methods of analysis have employed gas chromatography [7], with prior derivatization [8], high performance liquid chromatography [9] with mass spectrometry www.elsevier.com/locate/forsciint Forensic Science International 166 (2007) 209-217 [10]. Gas chromatography/mass spectrometry using chemical derivatives such as BSTFA [11] and HFBA [12] have also been reported.…”

Liquid chromatography–electrospray ionisation mass spectrometry for the determination of nine selected benzodiazepines in human plasma and oral fluid

“…Generally, capillary GC coupled to mass spectrometry (MS) is the method of choice for most of the toxicological analysis. Electronic impact GC-MS provides a selective analytical procedure for the analysis of BZP in biological samples [14][15][16][17] although several authors have demonstrated that the negative-ion chemical ionisation (NCI) is a more sensitive technique [18][19][20][21]. However, this method is generally tedious to apply because BZP are very polar and thermally unstable, so they cannot be evaporated and chromatographed without decomposition, unless previous derivatisation [22].…”

HPLC-DAD for analysis of different classes of drugs in plasma

“…[1][2][3][4][5][6][7] Liquid-liquid extraction can be tedious and time consuming, where as SPE extraction methods described in previous investigations though were efficient and reliable, but were not rapid enough for emergency toxicological screening and required the preparation of various buffers and solutions. Many investigators have directed their systematic toxicological analysis to the use of gas chromatography (GC), [5][6][7][8] thin-layer chromatography (TLC), [9][10][11] and high-performance liquid chromatography (HPLC) 12,13 as drug screening tools. GC coupled with mass detector can identify low concentrated compounds if only derivatization step is performed for certainly highly polar and thermolabile drugs and metabolites.…”