建立了茶汤中两种不同溶解度农药噻虫嗪和高效氯氟氰菊酯残留分析方法,并利用该方法研究了浸泡时间、温度、次数、茶叶形状和茶叶中残留量对两种农药浸出规律的影响。结果表明：恒定水温100℃时,浸泡不同时间,15βmin时,整叶茶和碎茶中噻虫嗪浸出率达最大值分别为81.2%和88.6%;25βmin时碎茶中高效氯氟氰菊酯的浸出率达到最大为5.5%,此时整叶茶中为0.41%。不同水温下冲泡15βmin时,噻虫嗪和高效氯氟氰菊酯在茶汤中的浸出率均随着浸泡温度的升高而增加,当水温100℃时,整叶茶和碎茶中噻虫嗪的浸出率达到最大,分别为83.9%和89.1%;高效氯氟氰菊酯的浸出率也达到最大,分别为0.55%和4.1%。恒定水温100℃,冲泡15βmin 3次,整叶茶实际样品中噻虫嗪和高效氯氟氰菊酯的浸出率随浸泡次数增加而逐次减小,总浸出率最大分别为93.25%和1.94%。茶汤中噻虫嗪总浸出浓度与它在成茶中的残留量呈线性关系Y=0.9267X–0.0336,R²=0.9954;高效氯氟氰菊酯总浸出浓度与它在成茶中的残留量呈二次函数关系Y=0.0026X²–0.0023X+0.0096,R²=0.9765。在此基础上对茶叶中噻虫嗪和高效氯氟氰菊酯残留量进行风险评估,结果表明饮茶摄入两种农药残留对人体健康影响的风险很小。

A residue analysis method for thiamethoxam and lambda-cyhalothrin in tea infusion was established, and the influence of brewing time, brewing temperature, tea shape and residue concentration in made tea to the brewing behavior from made tea to tea infusion were investigated by this method. The results showed that: when constant temperature of 100℃ for different brewing time (5~30βmin), the brewing rate of thiamethoxam were maximum at 15βmin, which were 81.2% in whole leaf tea and 88.6% in broken tea, the brewing rate of lambda-cyhalothrin reached the maximum of 5.5% at 25βmin in broken tea, and the whole leaf tea for 0.41%; after brewing in different temperature for 15 min, the brewing rates of thiamethoxam and lambda-cyhalothrin were increased according to the brewing temperature, when the temperature was 100℃, in the whole leaf tea and in the broken tea, the brewing rates of thiamethoxam were the maximum at 83.9% and 89.1%, respectively; and for lambda-cyhalothrin were the maximum at 0.55% and 4.1%, respectively. When constant temperature at 100℃, after brewing 15 min for three times, the brewing rates of two pesticides were decreased with the brewing times, and the total maximum brewing rates of thiamethoxam and lambda-cyhalothrin were at 93.25% and 1.94%, respectively. The extracting concentration of thiamethoxam in tea infusion from made tea were meeting the linear relationship, the equation was Y=0.9267X－0.0336, R²=0.9945, and the concentration of lambda-cyhalothrin in tea infusion extracting from made tea were meeting the quadratic function relationship, the equation was Y=0.0026X²－0.0023X＋0.0096, R²=0.9765. On the basis of research, the risk assessment on thiamethoxam and lambda-cyhalothrin in tea during drinking showed that the risk to human health via tea drinking was very small.