Decrease in the matrix effect of GC/MS by a gold-plated ion source

The matrix effect is often observed when trace levels of pesticides in agricultural products are analyzed by GC/MS. In this study, we created a gold-plated ion source that included an ion source body, a draw-out plate lens, and an interface socket. When agricultural products fortified with a pesticide at 100 ppb were tested by GC/MS equipped with a gold-plated ion source, the matrix effect was reduced. The rates of decrease in the matrix effect value in samples of potato, spinach, orange brown rice, and soybean were 2.3%, 14%, 20%, 38%, and 15%, respectively. The rate of decrease was especially significant in the sample of brown rice. This result showed that the gold-plated ion source effectively reduced the interaction between the food matrix and the ion source. (c) Pesticide Science Society of Japan