Applications Of New Solid-phase Extraction Technique In Determination Of Poisons From Criminal Cases

Along with the development of analytical techniques, many instrumentary analysis methods were introduced into analysis of poisons in criminal cases and have achieved a major breakthrough. However, due to the diversity of samples, development of appropriate pretreatment method is necessary to meet the need of instrument analysis.Fe3O4@Si02nano particles modified with C18groups were used as adsorbent of matrix solid-phase dispersion extraction to extract pesticides from water samples and hypnotics from urine samples, followed by GC-MS analysis. Extraction conditions including amount of magnetic particles, type and amount of elution solvent and extraction time were investigated to optimize the extraction conditions. The highest enrichment factor reached1015times. The extraction method was applied to the analysis of pond water in poisoning case and dimethoate and cypermethrin were determined with concentrations of9.0ng/Lå'Œ16ng/L, respectively. Experiment results show that using magnetic nano particles as adsorbent can accomplish the separation of assorbent and sample matrix easily by magnet with good reproducibility, high recovery, high enrichment fator and low LOD.Solid-phase extraction coupled with GC/MS/MS was applied to extraction and enrichment of nine hypnotics for qualitative and quantitative analysis. The developed method was applied into the analysis of hypnotics in human heart blood from real case. Moreover, ultrasonic wave assisted solid-phase extraction and liquid-liquid extraction coupled with GC/MS/MS were performed to analyze residues of organophosphorus pesticides in vegetable. The methods were proved simple, fast and sensitive.