Determination of Emamectin Benzoate in Eel, Halibut, and Shrimp Using QuEChERS-EDTA and LC-MRM

Abstract

As a part of efforts to establish the positive list system (PLS) in South Korea, a method to determine residual emamectin benzoate (EB) in various aquatic products using QuEChERS-EDTA and LC-MRM was developed. The developed method was validated in the aspects of specificity, linearity (correlation coefficient of at least 0.996), sensitivity (the limit of detection and the lower limit of quantitation ${\leq}5ng/g$), recovery (the recovery range of 87.4 and 96.2), and precision (the relative standard deviation of recovery between 0.9 and 13.5). Additionally, the validated method was successfully applied for monitoring EB contamination in eel, halibut, and shrimp collected from local food markets. To our knowledge, the present method is the first one to determine residual EB in various aquatic products at the level satisfying the PLS and could contribute to the establishment of the PLS in South Korea.

Figure 1. Chemical structures of emamectin B1a (EMA B1a) and emamectin B1b (EMA B1b).

Figure 2. Schematic diagram of the present method using QuEChERS-EDTA (the Q3 method) and LC-MRM

Figure 3. MRM chromatograms from blank eel (A) and standard (5 ppb)-spiked eel (B) analyses. S and C stand for the screening transition peak and the confirmatory transition peak, respectively.

Table 1. Properties of emamectin B1a (EMA B1a)

Table 2. Recovery of emamectin B1a (EMA B1a) at 5 ppb from different QuEChERS methods. Q1: the Standard Method EN 15662 [13]; Q2: the QuEChERS-EDTA method from [14]; Q3: the Q2 method with modification

Table 3. Matrix effect of emamectin B1a (EMA B1a) on eel, halibut, and shrimp samples

Table 4. Method validation information