Cleanup for Analysis of Residual Pesticides in Foods
To ensure the safety of the increasing number of imported food products, residue standards have been established in Japan for over 200 types of pesticides.
To allow efficiently inspecting for all these pesticides in foods, Japan's Ministry of Health, Labour and Welfare has developed a method for rapid analysis of residues in foods (multiresidue pesticide analysis method) that enables simultaneously analyzing multiple analytes (notified in 1997). This method uses a GPC cleanup method to partially automate the pretreatment process. Due to a partial revision of food standards in 1999, methods other than the test methods specified in the Food Sanitation Act may now be used.
Therefore, to further automate the process, Shimadzu now offers a Prep-Q system, which connects a GPC cleanup system to a GC-MS system online. This provides an even faster and labor-saving system for screening residual pesticides in foods.
First, an extract containing pesticides is obtained from the food sample and concentrated.
1. Use a GPC column to separate oil/fat and dye components from pesticide components based on differences in molecular weight.
2. Use a flow line switching valve to reject oil/fat and dye components and trap pesticide components in the sample loop.
3. Use the newly developed large-volume GC-MS injection method to inject the concentrated pesticide components trapped in the loop into the GC column.
4. Use GC-MS to simultaneously analyze multiple pesticide components (screening analysis).
Chlorine-based pesticides, pyrethroids, organophosphorus pesticides, nitrogen-based pesticides, and carbamate pesticides contained in agricultural products* * Excluding leachates from tea.
1. Simultaneous screening analysis of multiple analytes is now possible using a compact GPC column and large-volume sample injection into a GC-MS system.**
2. Connecting GPC-GCMS online cuts the analysis time in half.***
3. Downsizing the GPC column reduces solvent consumption dramatically to 1/200 of the normal level.****
4. Automation reduces manual operations and operator variability.
** Jointly developed based on the concept and direction from the Osaka Prefectural Institute of Public Health
*** Analysis time per sample is about 80 minutes (30 min for extraction, 10 min for GPC sample preparation and GC automatic concentration and injection, and 40 min for GCMS measurement).
**** About 1 mL of solvent is required per sample for GPC cleanup.
Prep-Q Method Requires Even Less Time Than the "Multiresidue Pesticide Analysis Method"
Examples of Mass Chromatograms and Mass Spectra of Pesticides in Potato Extract