PESTICIDE ANALYSIS WITH THE PULSED-FLAME PHOTOMETER DETECTOR AND A DIRECT SAMPLE INTRODUCTION DEVICE

New methods for fast, sensitive, and informative pesticide analysis in food products are described, These methods are based on sampling with a novel direct sample introduction device (DSI), gas chromatographic analysis, and pesticide detection with the pulsed name photometric det ector (PFPD), Sampling with the DSI is based on introduction of blende d fruit or vegetable in a small glass vial that retains the harmful no nvolatile residue and is disposed of after the analysis, The DSI-GC-PF PD combination provides several new features that are demonstrated and discussed: (a) Extract-free analysis is achieved with the DSI, which serves as an effective alternative to sample extraction and cleanup me thods, (b) Faster analysis is achieved through the use of the DSI due to the reduction of the upper GC program temperature, since the low-vo latility compounds are retained in the sample vial, (c) Relatively eff icient and uniform DSI thermal extraction and PFPD detection can be ac hieved, allowing the use of internal standards for pesticide calibrati on. (d) Higher sensitivity is provided by the PFPD as well as through the use of the DSI for sampling larger volumes of extract solutions. ( e) Sulfur interference is eliminated with the PFPD in its phosphorus-s elective detection mode, using software exploiting differences in S an d P delayed pulsed name emission time dependence. (f) Sulfur pesticide s are effectively analyzed by the PFPD in its sulfur-selective detecti on mode at the usual required levels and with less matrix interference than with NPD in the nitrogen mode, (g) Simultaneous sulfur and phosp horus pesticide analysis is demonstrated, including heteroatom identif ication and the provision of P and S atom ratio information in the ana lyzed pesticide.