To establish a method for the simultaneous detection of 154 kinds of pesticides and their metabolites in roasted coffee by liquid chromatography-quadrupole/linear ion trap mass spectrometry.
The samples were extracted with 1% acetic acid in acetonitrile, followed by salting-out and dehydration using sodium chloride and anhydrous magnesium sulfate. The lipids in the extract were then removed with the enhanced lipid removal product Bond Elut EMR-Lipid. Further purification was performed using Carbon S and primary secondary amine (PSA) solid-phase sorbents. Analysis was carried out via multiple reaction monitoring, information-dependent acquisition and enhanced product ion (EPI) scanning, combined with library searching against the EPI spectral library of 154 kinds of pesticides in a multi-step mode. Matrix-matched external standard method was adopted for quantitative determination.
The linear relationship of 154 kinds of pesticides was good linearity with in the range of 2–200 ng/mL (r>0.990). At the spiked levels of 0.01, 0.05 and 0.10 mg/kg, the average recovery rates were 70.4%–117.5%. The relative standard deviations (RSDs, n=6) were 1.7%–14.9%. The limits of detection and limits of quantitation of the method were 0.07–3.00 µg/kg and 0.25–10.00 µg/kg, respectively. The method was accurate and effective. It complied with the testing requirements for pesticide residue limits in China, the European Union and Japan.
This method is simple, rapid and reliable, and can be used for the rapid screening and quantitative analysis of 154 kinds of pesticide residues in roasted coffee.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |