Analysis of anaesthetics and analgesics in human urine by headspace SPME and GC

Abstract

The determination of widely used anaesthetic and analgesic drugs in biological fluids is of major clinical importance. Typical methods used for sample preparation employ liquid-liquid extraction protocols which are complex, costly, not handy and not amenable to automation. In the present communication, we report the development of a methodology that employs headspace solid-phase microextraction (HS-SPME) for the determination of four anaesthetic (lidocaine, midazolam, diazepam and ketamine) and three analgesic drugs (fentanyl, remifentanyl and codeine) in human urine. Important parameters controlling SPME were studied: selection of SPME fibre, type and amount of salt added, preheating and extraction time, extraction temperature, sample volume and desorption time. GC with nitrogen phosphorus detection (GC-NPD) facilitates sensitive and selective detection of the anaesthetics. The developed method renders an efficient tool for the precise and sensitive determination of the anaesthetics and analgesics in human urine (RSDs ranged from 7.7 to 12.6%, whereas LODs ranged from 0.01 to 1.5 ng/mL). The method was applied to the determination of the anaesthetics and analgesics in human urine from patients that had undergone coronary by-pass surgery operations. The proposed protocol can function as an attractive alternative for clinical acute intoxications and medico-legal cases.

Determination of midazolam and 1-hydroxymidazolam from plasma by gas chromatography coupled to methane negative chemical ionization mass spectrometry after sublingual administration of midazolam

“…The mixed-mode SPE method has been used for the determination of midazolam and its metabolites in oral fluids [21], plasma [15,37], serum [24], and urine [15,26,28,31]. Midazolam has also been assayed from human plasma by direct immersion solid-phase microextraction (SPME) using a polyacrylate fiber after plasma deproteinization step [13] and from human urine by headspace-SPME using a polydiemethylsiloxane fiber [19].…”

“…Several chromatographic methods have been described for the simultaneous determination of midazolam and 1-hydroxymidazolam including reversed-phase or normal phase high performance liquid chromatography (HPLC) coupled with single wavelength or photodiode-array ultraviolet detectors [15][16][17][18]. Midazolam has been measured from human urine and plasma by gas chromatography with a nitrogen phosphorus detector (GC-NPD) and/or an electron capture detector (GC-ECD) [19,20].…”

Separation and determination of anesthetics by capillary electrophoresis with mixed micelles of sodium dodecyl sulfate and Tween 20 using electrochemiluminescence detection

“…It is necessary to determine local anesthetics sensitively for biochemical and clinical analysis. To date, several analytical assays have been proposed such as gas chromatography (GC) , liquid chromatography (LC) and capillary electrophoresis (CE) .…”

Postmortem Redistribution of Lidocaine after Epidural Anesthesia Accidental Death

“…As far as forensic toxicological identification, analytical methods for lidocaine are well developed and documented [9][10][11]. However, there is no obvious evidence indicated the cause of death in anesthesia, difficult to distinguish the cause of death between accident and natural.…”