Pesticides are used in a variety of different ways during the production of food. Ranging from preventing crop damage by insects, rodents and molds during growth to prolonging storage of food after harvest. Because of the frequent usage, the residual pesticides are often found in many agricultural products and their monitoring and control is an important step in achieving and maintaining overall food safety in the modern society.

Mass spectrometry in connection with different separation techniques currently represents the main analytical approach for determination of residual pesticides in food. Traditionally, samples need to be collected and send to a laboratory for analysis using techniques such as GC-MS or HPLC-MS, which are costly and time-consuming. In addition, the conventional mass spectrometry usually requires laborious sample pretreatment, which does not allow for immediate in-situ sample determination. Presented here is an application of Thermal Desorption ElectroSpray Ionization (TD-ESI) for pesticide screening coupled to a portable mass spectrometer. TD-ESI is a mass spectrometry technique from the family of ambient ionization methods that utilizes very simple probing of different surfaces with no or limited sample pretreatment while it is still noted for its selective and sensitive detection capabilities. In TD-ESI a solid surface or a liquid sample is touched by a simple metallic probe that absorbs the analyte. The probe is then inserted into a heated tube and the desorbed analyte is carried by gas flow into an orthogonally mounted electrospray. The electrospraty plume extracts the analyte and further ionization and ion introduction follows the conventional electrospray mechanism. Bayspec’s Portability™ mass spectrometer is less than 10kg highly portable and battery operated linear ion trap mass spectrometer with atmospheric pressure inlet (API). When TD-ESI is combined with Portability™ then it is possible to perform fast in-field detection of analytes including residual pesticides, directly of the surfaces of fresh food products without any sample pre-treatment. Fast pesticide screening by Portability™ mass spectrometer can immediately disclose fake organic food products as well as to discover elevated levels of residual pesticides.