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Sample Extraction Methods

Pesticides in Baby Food: Sample Extraction Methods

July 1, 1995

Appendix 1

 

Multi-Residue Screens

 

Luke Extraction as per PAM1 (Pesticide Analytical Manual Vol.1)

Modifications:

 

 

 

  • 160 ml of filtrate instead of 80 ml. Final volume 10 ml.
  • ECD Clean up: 2ml acetone extract and evaporated with N2 to dryness.

 

Dissolve in Petroleum ether. Transfer pet ether to pre-conditioned Supelco 1gm Florisil column, and elute with 10ml 10% acetone in pet ether. Evaporate to 5ml final volume.

 

N-Methyl Carbamate (HPLC)

 

Luke Extraction as per PAM1, then filter 1 ml acetone extract through 0.45 filter into autosampler vial.

 

Organosulfur Pesticides (Propargite)

 

Luke Extraction as per PAM1

 

Thiabendazole

 

Luke Extraction as per PAM1, then use 5ul of filtered acetone extract.

Eluent 1:

 

 

 

 

 

 

 

  • 500ml methanol
  • 450ml Water
  • 50ml Acetic Acid
  • 4gm Sodium Acetate Trihydrate

 

Eluent 2: 70:30 IP Solution:methanol (confirmations)

 

Benomyl

 

Luke extraction as per PAM1, then 2 ml of acetone extract was evaporated to dryness with N2, dissolved in 1 ml of methanol and 1 ml of IP solution is added. The sample is set overnight to convert any residual benomyl to MBC.

 

 

 

  • Eluent: 70:30 IP solution: methanol
  • IP solution:1 gm Sodium Decanesulfonic acid, 7ml H3PO4, 10ml triethylamine to 1 l water.

 

 

ETU

 

100 grams of product was extracted in methanol-aqueous sodium acetate solution, filtered with diatomaceous earth and eluted in methylene chloride as per Krause, JOAC 72: 6,1989.

 

  • Eluent: 0.025 M Phosphoric Acid