Determination by glyphosate and aminomethylphosphonic acid in crops by capillary gas chromatography with mass-selective detection: collaborative study.
A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries; 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.
Alferness
P L
PL
Zeneca Ag Products, Western Research Center, Richmond, CA, USA. palferness@biomarinpharm.com
Wiebe
L A
LA
D002849:Chromatography, Gas / Q000379:methods*; D018556:Crops, Agricultural / Q000737:chemistry*; D005998:Glycine / Q000031:analogs & derivatives* / Q000032:analysis*; D006540:Herbicides / Q000032:analysis*; D007753:Laboratories / Q000592:standards; D009754:Nuts / Q000737:chemistry; D009943:Organophosphorus Compounds / Q000032:analysis*; D011786:Quality Control; D015203:Reproducibility of Results; D013025:Glycine max / Q000737:chemistry; D003313:Zea mays / Q000737:chemistry; D000097797:Glyphosate
D005998:Glycine; D006540:Herbicides; D009943:Organophosphorus Compounds; D000097797:Glyphosate; C036423:1-aminomethylphosphonic acid