| Background Comparing to other medicine, the development of anesthesiology has a younger history. Although anesthesiology has made great progress in the last thirty years and the rates of death relative to anesthesiology decline significantly, the accidents caused by anesthesia still can't be avoided. At present few clinical anesthesia is finished with a single drug, because there is no one drug achieving full effects of the anaesthetic requirements. Hence, the combined application of narcotic drugs make the drugs used in the operation more complicated. In the field of pharmaceutical analysis, the determination of various drugs largely confined to the same kinds of drugs under the same analytic method condition, such as benzodiazepines and barbiturates, etc. The study of simultaneous determination of drugs based on the compatibility of different kinds of clinical medicine drugs has less been reported, especially in the medical dispute cases involving anesthetic drugs. Therefore, based on the compatibility use of clinical drug use, the study of simultaneous determination of different kinds of drugs is expected to provide a novel derection and method in the field of pharmaceutical analysis and forensic toxicological analysis.Objective 1.To estblish the simultaneous determination of propofol, midazolam and fentanyl in biological samples. 2. To provide a quick, simple, reliable analytical method for determination of anaesthetics in medical dispute cases. 3. To monitor the blood concentration of anaesthetics in clinical operation.Methods 1. Gas chromatography analysis methods: After adding buffer, the biological samples were extracted by a mixture solvent of n-hexane: dichloromethane: isopropanol(50:45:5, v/v/v) in liquid-liquid extraction, then detected qualitatively on gas chromatography – mass spectrometry(GC-MS). A quantitative analysis for propofol by gaschromatography equipped with a flame ionization detector(GC-FID), midazolam and fentanyl by gas chromatography equipped with nitrogen phosphorus detector(GC-NPD) were performed. 2. Qualitative analysis: chromatography condition was as follows: a DB-5 capillary column used for compounds separation. A programmed oven temperature was performed as follows: the initial oven temperature was 60 ?, hold for 1 minute, then increased to 300 ? at a rate of 15 ?/min, hold for 10 minute. The temperature of the injector was 280 ?. The injector was operated in the spiltless mode. Carrier gas: high purity helium, flow rate was 1 m L/min. The injection volume was 1 ?L. Mass spectrometry condition: the ionization energy was 70 e V and the transfer line temperature was 280 ?. The electron impact(EI) ion source, quadrupole mass analyzer, and the interface temperature were maintained at 230, 150, and 280 ?, respectively. Thymol, estazolam and papaverine were the internal standards of propofol, midazolam, and fentanyl, respectively. The MS was operated in the selected ion monitoring(SIM) mode : the ions m/z 135, 150 for thymol, 163, 178 for propofol, 310, 325, 312 for midazolam, 245, 146, 189 for fentanyl, 338, 324, 308 for papaverine, and 259, 294, 239 for estazolam. 3. Quantitative analysis: The standard curves were obtained by plotting the peak-area ratios of analytes versus internal standards against the concentration of analytes.Results The developed method for the qualitatively simultaneous determination of anaesthetics by GC-MS was successfully applied. The order of the target analytes were as follows: 7.670 min for thymol, 8.326 min for propofol, 17.017 min for midazolam, 17.664 min for fentanyl, 18.347 min for papaverine and 19.031 min for estazolam. The limits of detection were between 0.5 and 50 ng/m L or ng/g(S/N?3). The endogenous components has no interfere with the detection.Using the quantitatively analysing method of GC-FID/NPD, the linear relationships were well. The lower limits of quantitation were between 1.0 and 100 ng/m L or ng/g(S/N?10). The spiked samples average recoveries of analytes were between 85.18% and 129.17%. Intra day precisions were between 2.94 % and 9.78 %. Inter day precisions were between 0.86 % and 9.19 %.Conclusion The developed GC-MS and GC-FID/NPD method could simultaneous determinate multiple anaesthetics qualitatively and quantitatively. The method is simple for specimens pretreated, rapid, accurate, reliable and practicable. It is suitable for forensictoxicological analysis. Scientific basis are provided in such medical dispute cases. This method is also suitable for monitoring the blood concentration of anaesthetics in clinical operation. |
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