Development of an isotope dilution liquid chromatography/tandem mass spectrometry method for the accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage reference materials

Journal of Analytical Science and Technology

Table 1 Measurement results of gravimetrically fortified samples to kimchi cabbage powder by ID-LC/MS/MS at various mass fractions

Analytes	Fortified value (mg/kg)	Measured value (mg/kg)^a	Difference (%)^b
Imidacloprid
#1	2.482	2.503 ± 0.033	0.85
#2	2.481	2.503 ± 0.025	0.85
#3	0.625	0.620 ± 0.006	− 0.88
#4	0.491	0.487 ± 0.005	− 0.89
#5	0.245	0.246 ± 0.003	0.78
#6	0.246	0.246 ± 0.003	0.21
Clothianidin
#1	2.923	2.998 ± 0.032	2.58
#2	2.921	3.002 ± 0.036	2.77
#3	0.736	0.735 ± 0.004	− 0.09
#4	0.578	0.583 ± 0.003	0.72
#5	0.288	0.290 ± 0.002	0.55
#6	0.289	0.290 ± 0.004	0.31
Thiamethoxam
#1	2.760	2.757 ± 0.034	− 0.10
#2	2.758	2.765 ± 0.036	0.22
#3	0.695	0.701 ± 0.008	0.91
#4	0.546	0.550 ± 0.006	0.75
#5	0.272	0.276 ± 0.004	1.67
#6	0.273	0.277 ± 0.003	1.61

^aThe number after ‘±’ is the expanded uncertainty of the preceding value with the level of confidence of 95%
^bRelative difference of the measured value from the gravimetrically fortified value