Determination Of Organic Pollutants In Solid Sample By Hollow Fiber-based Liquid-phase Microextraction Combined Gas Chromatography-mass Spectrometry

Hollow-fiber based liquid-phase micro-extraction (HF-LPME), which was developed on basis of the hanging drop liquid-phase micro-extraction (HD-LPME), functions as a new quick, convenient, environment-sound sample pre-procession technology combining extraction, collection with sample injection and featuring minimization & automation capability.Until now it has been applied to pre-procession of various materials'analysis, not only to sampling test in biological & environmental fields, but also to other areas as food & health industry, being focused on by different analysis men & testers recently. Report is rare about HF-LPME applying directly to solid organism sample test, such as soil, whereas most parts to water sample analysis at home and abroad currently. Therefore, two parts below, HF-LPME being applied to determination & analysis of solid sample as soil & milk powder, was research on according to unique features of HF-LPME.Three kinds of Pyrethroid pesticide were selected as research objects, and their volume were measured with HF-LPME & GC-MS, eventually optimum extraction conditions being determined, as well as chromatography and mass spectrometry conditions. Results show that on the condition of cyclohexane as extracting agent, rate of water/soil as 3∶1, ultrasonics time as 5 min, stirring velocity as 900 r/min, extracting time as 20min, temperature as 25°C, adding 25 % minerals NaCl, and pH as 4, linear range of three kinds of Pyrethroid pesticide (bifenthrin, cypermethrin & deltamethrin) were respectively 0.01～25 mg/kg,0.5～50 mg/kg and 0.5～50 mg/kg, as limits of detection respectively were 0.003,0.020 and 0.040 mg/kg, relative standard deviation(RSD) were 4.3 %,4.7% and 8.6 %. In this way, recoveries were determined aiming to real samples with different adding standard soil samples, respectively as 1mg/kg, 5mg/kg and 10 mg/kg. The result shows that recoveries of the first one were 109.4%, 113.8% and 83.6%. The second were 112.9%, 111.1% and 84.6%, and the third were 113.2%, 112.7% and 88.6%. This method could be used in quick determination of pyrethroid pesticide in soil.A new quick & direct measuring method was researched of BPA in solid sample of milk powder by pre-procession of HF-LPME on basis of GC-MS. Results show that on the condition of benzene as extracting agent, rate of water/solid as 4∶1, ultrasonics time as 3 min, stirring velocity as 650 r/min, extracting time as 15min, temperature as 35°C, adding 20 % minerals NaCl, and pH as 6.5, it achieved the best extraction effect, with linear range as 0.01～25 mg/kg,linear equation as c = 1E-05A - 0.0789,Correlation coefficient as 0.9992, the limits of detection as 0.0002 mg/kg,and RSD as 4.9%.In conclusion, as a simple, quick, economical, pollution-free method, HF-LPME could be applied to pre-procession of solid sample, and achieve a sound extraction effect.