The detection and analysis of organo-nitrogen pesticides (ONP's) that may be present in Luke extracts of fresh produce presents a particular challenge. High background is generated by natural food components that respond to the nitrogen-selective detector used in the accepted gas-chromatographic regulatory methodology. Replacement of the nitrogen-selective detector with a mass spectrometer dramatically improves both selectivity and sensitivity. This method employs a GC/MSD operating in the selected ion mode (SIM), programmed to scan only for ions representative of the target compounds, thereby eliminating most background interferences. By using known retention times, many different ion "groups" that include pesticides with similar retention times can be created to effectively screen for most ONP's. When GC/MSD/SIM results from routine regulatory samples containing incurred residues were compared with results obtained via established GC and HPLC methods, agreement between methods was excellent for several pesticides in a variety of matrices. To date, this method has been used to analyze Luke extracts of approximately 1000 fruit and vegetable samples for ONP's. Eleven different ONP's have been detected during this time period, well in excess of the total number of ONP's reported as being found in 1993 and 1994 using conventional regulatory methods.