Application Of Hollow Fiber Liquid-phase Microextraction For Analysis Of Opiates Drugs

The situation of drugs has been increasingly serious in recent years,Drug-related crimes have turned to be more various,the number of drug users has been constantly growing and the public order cases and criminal cases caused by drugs abuse have gradually increased,which have severely endangered social security.There were 2,345,000 registered drug users nationwide including 980,000 opium-abused users,which were accounting for 41.8% of all by the end of 2015,showing that conventional problems with opium-related drugs have not yet effectively resolved in China.Moreover,codeine is the primary drug that the youth abuse,and the addictive prescription drug such as tramadol and methadone etc.have become even more serious invisible social problems.China's anti-narcotics is facing tremendous pressure and challenge.Concerning the opiates drug test of drug users,pretreatment methods are time consuming and require of organic solvent in large quantity.Therefore,the development of fast,simple,inexpensive,environmental-friendly and automatic sample pretreatment methods is the hot-button topic in analytical chemistry,which has great and practical significance to drug testing.Hollow-fiber liquid-phase microextraction(HF-LPME)technique is recently developed sample pretreatment technique,which employs hollow fiber as organic solvent carrier with the functions of sampling,extraction and concentration.It decreases the quantity of organic solvent,has better enrichment capacity and purification performance,andcan be directly followed by instrument analysis.The technique has been in preliminary application in pharmaceutical analysis and environmental chemistry.This study focused on HF-LPME and its application in drug testing,taking opiate drugs as target analytes,,and aiming at extending this technique to forensic science.Based on previous studies,the following researches about sample pretreatment technique were conducted in this paper.1.This study set up a liquid-liquid-liquid three-phase extraction apparatus coupled with high performance liquid chromatography to analyze the metabolite of heroin in urine(i.e.morphine,6-acetylmorphine and codeine).The experiments optimized the type of hollow fiber membrane and extraction conditions affect extraction performance such as extraction solvent,pH of sample phase and receive phase,extraction time,agitation rate and salt effect and so forthwere investigated.The enrichment factor(EF)of this method was in the range of 85~165,the limits of detection(LOD)was achieved in the range of 10~50ng/mL with relative standard deviation(RSD)was lower than 7.4%,The method has applied to the testing of heroin-using suspects and cough mixture containing codeine with success.This HF-LPME method possess some advanced feature such as high selectivity,high enrichment factor,high stability and reliability,providing a kind of green pretreatment method of analyzing addicts in the public security department.2.Using methadone and tramadol as target analytes,the paper developed hollow fiber liquid extraction coupled with high performance liquid chromatography method,for the both drugs respectively,Different extraction operation modes were used respectively to make a comparison of them in operation and the effect of extraction,aiming to determine the optimal analysis mode of hollow fiber extraction.By optimizing the experimental conditions,the two compounds were obtained higher enrichment factor(more than 100 times)and the lower detection limit(tramadol is 10 ng / mL,methadone is 10ng/ mL),with the recovery in the 54 ~80%;RSD less than 6.8%.According to the experiment,the extraction mechanism of hollow fiber was discussed,which can be used to predict the enrichment effect among similar compounds.3.Using ionic liquid as a new type solvent in extraction,the paper established ionic liquid assisted hollow fiber three phase liquid microextraction method,to extract and enrich four opiates drugs,morphine,tramadol,codeine,methadone in urine.Using ionic liquid as solvent extraction,the study showed it not only has good extraction performance,but also has a very good barrier function,which can eliminated macromolecules interference in the complex matrix effectively.At the same time,through adjusting the received phase and sample phase pH and using trioctylphosphine oxide to assist the extraction,high enrichment factor(98 ~178 times)and the lower detection limit(below 10 ng /mL)were obtained.