Determination of Isocarbophos in Bio-testing Materials by GC-MS

Isocarbophos in bio-testing materials was separated by SPE on Oasis HLB SPE column from sample solution buffered at pH 4.5 with PBS.The SPE column was dried by centrifugation and eluted with ethylacetate to desorb isocarbophos from the column.The eluate was concentrated to 1 mL by N2-blowing and used for GC-MS analysis.Conditions for GC-MS analysis ware studied and the optimum parameters were given.Relatively high pre-column pressure,high flow-rate of carrying gas and low temperature at the connection inlet from GC to MS were adopted to reduce or avoid thermodecomposition of sample.Based on the mass spectrogram of standard isocarbophos,the attribution of strong ion fragments were confirmed and standard spectrum database of isocarbophos was proposed,which is the basis of qualitative analysis of isocarbophos.Range of linearity found for determination of isocarbophos was between 0.05-100 mg·L-1.Values of average recovery,RSD (n=5) and limit of detection (3S/N) were found to be 93.3%,2.5% and 0.05 mg·L-1 respectively.