The residual levels and dissipation rates of 1-naphthylacetic acid in garlic and soil were determined by high performance liquid chromatography-tandem mass spectroscopy (HPLC-MS/MS). The limit of quantification (LOQ) of the developed method was 0.005 mg/kg. The half-lives of 1-naphthylacetic acid in garlic plants and soil were 0.80-1.4 days and 0.94-2.0 days, respectively.
The final residues of 1-naphthylacetic acid in garlic, garlic sprout and soil could not be detected and were all below 0.05 mg/kg (the MRL of EU). Results of the ultimate residues in garlic and soil showed that this pesticide is safe to be used under the recommended dosages.