190 / 311
3/9/2017
6
Conclusion: M3’s pure acetonitirle extraction has achieved relatively good results for pesticides of different polarities, which
takes a balanced, stable and similar to straight trend line. While M1’s hydration increases the extraction efficiency of certain
polarity water-soluble pesticides; but the adoption of hexane liquid/liquid partitioning further causes certain loss of extracted
polarity pesticides, leading to an arc trend line high in the middle and low at both ends; Overall speaking, M3’s extraction
efficiency is superior to M1’s. For M2, hydration procedures are likewise adopted, which increases the extraction efficiency of
the pesticides of strong polarities and lowers the extraction efficiency of the pesticides of weak polarity. Because of the
application of SPE, the line of M2 is similar to downtrend line with the front rise and the back-end fall.
The recovery change diagram for 7 polarity sectors by the three methods
M1
M2
M3
0.0
20.0
40.0
60.0
80.0
100.0
0.3
1.6
2.6
3.5
4.5
5.4
6.0
average of REC
median of logKow
Spiked level 0.1mg/kg
Special study on the effect of tea hydration on the efficiency of the analytical method
Correlation comparison of fortified recoveries of 456 pesticides with pesticide logKow values with the
three methods of M1, M2 and M3
Organization and implementation of AOAC collaborative study
USA
Canada
Germany
Spain
Italy
Belgium
Japan
Korea
India
China
Taiwan
America
：
USA, Canada; Europe: Germany, Spain, Italy, Belgium; Asia: Japan, Korea, India, China and Taiwan
Collaborators for AOAC collaborative study: 30 labs from 11 countries and regions participated in the
collaborative study by GC-MS, GC-MS/MS and LC-MS/MS