Rapid analysis of urinary opiates using fast gas chromatography–mass spectrometry and hydrogen as a carrier gas

A sensitive and specific fast gas chromatography–mass spectrometry (FGC–MS) analytical method using hydrogen as a carrier gas is developed for the rapid simultaneous determination of morphine, codeine, hydrocodone and hydromorphone in human urine. Urine samples were spiked with deuterated internal standards, morphine-d3, codeine-d3, hydrocodone-d3 and hydro-morphone-d3, subjected to acid hydrolysis, treated with hydroxylamine to convert the keto-opiates to oximes and then extracted using a positive pressure manifold and silica based solid phase extraction columns. The extracts were derivatized using BSTFA with 1% TMCS.Gas chromatographic–mass spectrometric analysis was performed in electron ionization mode by selective ion monitoring, using hydrogen as a carrier gas, a short narrow bore GC capillary column, and fast temperature program, allowing for a rapid analytical cycle to maximize the instrument time for high throughput laboratories. While maintaining specificity for these drugs, concentrations in human urine ranging from 50 to 5,000 ng/mL can be measured with intraday and interday imprecision, expressed as variation coefficients, of less than 2.3% for all analytes within a run time of less than 3.5 minutes.