| Sample pretreatment is an indispensable and weaker procedure in analyzing process, especially for bio-samples, because of the complex matrix, low concentration, interference to the determination or pollution to the apparatus. Samples must be suitable for testing and the analytes should be preconcentrated some times. Although the functions of modern analytical instruments have been improved a lot, the quality of sample pretreatment still has effect on the results. Therefore, it plays a rule in analytical chemistry that looking for simpler, more efficient, quicker and environmental friendly sample pretreatment methods.A new type of sample preparation technique-solid-phase microextraction (SPME), was developed, which included syringes fiber SPME and in-tube SPME. It combines with pre-separation and pre-concentration. The operating of SPME requires no solvent or a small amount of solvent(less than 50 u 1), that reducing solvent consumption and avoiding environmental pollution.In-tube SPME-GC/FID or GC/MS methods were set up to determine drugs and poisons in bio-samples. A home-made multi-sample solid-phase microextraction equipment was used to deal with up to fifteen samples simultaneously. Comparing with the method in literature report, the multi-sample microextraction equipment is easy to make. The process of microextraction can be accomplished in few minutes. The eluate can be used repeatedly or by other methods.Purpose: Set up methods to determine drugs and poisons in bio-samples by using in-tube SPME-GC/FID or GC/MS.Method: The influential factors to SPME were selected, that were type of microextraction phase, capillary column length, sample volume, flow-rate of sample, desorption solvent, desorption solvent volume, desorption solvent flow rate, pH of sample. Find out notable and non-notable influential factors by the orthogonal experimental design. Set up method to examine abused drugs, pesticides, poisons in biology fluid with in-tube SPME-GC-FID, GC-MS.Result: The result of the orthogonal experimental design show that pH ofsample and desorption solvent volume are notable influential factors in in-tube SPME.The concentration of the analytes is tip-top when the volume of desorption solvent is 10ul. 30ul can elute all of the extracted analytes. The pH of sample effecting amount of extracted compounds, namely feeble acidic condition is in favor of acidic analytes, basic condition is favor of basic ones. By using a 120cm long capillary column, 1.0mL sample and methanol as elution solvent, the flow rate of desorption solvent shoes less influence to extraction result, so higher flow rate of drugs and poisons with in-tube SPME-GC-FID, GC-MS show that in the range of 0.1~10.0ug/mL the linear correlations are fine (r>0.99), the recoveries are ranged from 0.01% to 7.2%, the rate of enrichment are ranged from 0.5%~86.8%, RSD less than 13.0%. The results of quantity and quality are all accurate for the artificial and real samples.Conclusion: The subject supplies a faster and accurate method to determination of drug and poisons with in-tube SPME-GC-FID or GC-MS. |
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