Extraction of pesticide residues in tea by water during the infusion process

The extraction rate of pesticide residues in water during the infusion process is dependent on the water solubility. The extraction of pesticide residues by boiling water can be regarded as a reversible equilibrium between adsorption and dissolution. The influence of chemical degradation is not important. When the water solubility is lower than 5 mg/kg, the extraction rate is 1-4%. Within the water solubility range of 10-150 mg/kg the extraction rate (Ri) is very sensitive to the water solubility (S); the relationship can be described as Ri = 59.8log S-42.5. When water solubility is higher than 170 mg/kg, the extraction rate is 90-100%.