Abstract:

A high performance liquid chromatography method was developed for determining chemical hybridizing agent
SQ-1 and its dissipation curve in leaves and spikelets of foxtail millet. The samples were extracted with acetonitrile,
cleaned up with N-propylethylenediamine (PSA) and quantified by the external standard method. There was a good linear
relationship between the peak area and concentration of SQ-1 over the range from 1 to 1 000 mg/L, and the linear equation
was y = 30 377x + 27 634, with a correlation coefficient of 0.999 9. The lowest detectable concentration was 0.05 mg/kg.
The mean recoveries of SQ-1 in leaves and spikelet of foxtail millet varied from 87.0% to 95.5% with a relative standard
deviation ranging from 0.74% to 2.28% at fortification levels of 10–500 mg/kg. The results indicated that SQ-1 could be
transported from leaves to spikelets. The trend of SQ-1 residual dynamics was first increased and then decreased. The halflives
of SQ-1 were 1.83–2.08 days in leaves and no SQ-1 pesticide residues were detected after 21 days. The half-lives of
SQ-1 were 25.21–28.41 days in spikelets, and its degradation rate in spikelets was significantly lower than in leaves.

Key words: foxtail millet, chemical hybridizing agent, residues, degradation kinetics, high performance liquid chromatography (HPLC)