GC Determination of Organochlorine Insecticides in Orange Juice with Solid Phase Microextraction

A new extraction probe prepared by coating nanocarbon tube on stainless steel wire was used in the solid-phase microextraction (SPME) of organochlorine insecticides which were determined by GC with electron-capture detection. In the GC-analysis,SPME was integrated with the head-space technique (HS-SPME). Various factors influential to the HS-SPME,i.e. time and temperature of extraction,ionic strength,kind of organic solvents,volume of headspace,pH value of the sample solution and its dilution,etc.,were studied and optimized. Eight insecticides were determined with ranges of linearity within 0.05-6.0 μg·L-1,and detection limits (S/N=3) ranged from 0.003-0.022 μg·L-1. Using orange juice sample as matrix,tests for recovery and precision were made by addition of standard solutions of the insecticides,giving values of recovery in the range 71.0%-131.0%,and RSD′s (n=6) less than 10%.