Objective: To establish methods for determining residual of imidacloprid and spinosad in Salviae Miltiorrhizae Radix et Rhizoma

and investigate dynamic residual of these two pesticides. Method: Samples were extracted with organic solvents

purified by solid phase extraction cartridges and detected by HPLC-DAD. Result: These two pesticides were pretreated by solid phase extraction (SPE) method

and purified more thoroughly.Detection methods had high sensitivity

good reproducibility

accuracy

precision and detection limits were in line with requirements of determination of pesticide residues.Degradation dynamics data showed that considering residues of 2 h as initial residues

half-life periods (t1/2) of imidacloprid and spinosad were 3.65 d and 1.64 d.It showed that spinosad degraded faster than imidacloprid in the beginning.After one day

degradation curves of imidacloprid and spinosad in Salviae Miltiorrhizae Radix et Rhizoma consistented with first-order kinetic equations

t1/2 of them were 6.93 d and 11.55 d.It showed that spinosad had a longer duration of pesticide.At the same dosage level of pesticide

residue of spinosad was lower than imidacloprid

it showed that safe periods of spinosad was shorter than imidacloprid.The final residues of imidacloprid in soil and product were 0.02 mg·kg-1 and 0.18 mg·kg-1

and spinosad was not detected (<1.9 μg·kg-1) which showed that the final residue of spinosad was lower. Conclusion: It is concluded that in Salviae Miltiorrhizae Radix et Rhizoma planting

spinosad can be an ideal alternative pesticide to imidacloprid.