GB/T 5009.218-2008Determination of multi pesticide residues in fruits and vegetables (English PDF)

2.1 Principle

Sample water - acetone extract homogeneous, methylene chloride liquid - liquid partition, gel column purification, and then by the activated carbon solid-phase column purification, washing

Off was concentrated and dissolved constant volume, gas chromatography - mass spectrometry (GC-MS) measurement and validation, external standard.

2.2 Reagents and materials

Unless otherwise specified, the reagents were of analytical grade and water for the two water conductivity 25 °C <=0.10mS/m.

2.2.1 acetone (C3H6O)

residual level.

2.2.2 dichloromethane (CH2Cl2)

residual level.

2.2.3 ethyl acetate (C4H8O2)

residual level.

2.2.5 n-hexane (like -C6H14)

residual level.

2.2.6 Methanol (CH4O)

residual level.

2.2.7 Benzene (C6H6)

residual level.

2.2.8 Sodium chloride (NaCl)

pure class distinctions.

2.2.9 anhydrous sodium sulfate (Na2SO4)

650 °C burning 4h, stored in a sealed container for later.

2.2.10 aqueous sodium chloride solution

20g/L.

2.2.11 activated carbon SPE column (pesticarb)

0.5g, or rather who, prior to use 5mL hexane pre-rinse.

2.2.13 standard solution

2.2.13.1 standard stock solution

namely, accurately weighed amount of each pesticide standards, with acetone or appropriate solvent (see Table A.1 and

Table A. 2) preparation of a concentration of standard stock solution 500µg/mL ~ 1000µg/mL of. The solution can be stored at 0 °C ~ 4 °C refrigerator

12 months.

2.2.13.2 intermediate standard working solution

According to the nature of the pesticide and its retention time is different from the 211 kinds of pesticide into A, B two

Each pesticide standard stock solution group were accurate pipetting volume can be diluted to a suitable concentration with acetone A mixed group of standards needed

Group B and intermediate working fluid intermediate mixed standard working solution. This solution can be stored for 6 months at 0 °C ~ 4 °C refrigerator.

2.2.13.3 mixed standard working solution

accurate Pipette a volume of A group of intermediate mixed standard working solution and intermediate mixed standard working group B

Liquid, diluted with n-hexane may need to be suitable concentration of group A working standard solutions A and B mixed standard working solution. The solution can be

0 °C ~ 4 °C refrigerator for 1 month.

2.3 instruments and equipment

2.3.1 Gas chromatography - mass spectrometry

source with electron impact (EI).