ANALYTE: Carbendazim, a metabolite of benomyl
RANGE OF DETECTION: 25 to 500 ppb
Benomyl/Carbendazim RaPID AssayÒ Kit and Sample DiluentReagents: acetone (pesticide grade), sodium chloride Equipment: homogenizer or blender with acetone resistant container cup, 50 mL polypropylene conical tubes, 13 x 100 mm glass test tubes, serological pipets, micropipette (50mL), vortex mixer, centrifuge (optional), scale or balance, nitrogen gas.
SAMPLE PREPARATION: Chop the tomato sample to be analyzed coarsely by hand or in a food processor.
With homogenizer: Add 20 mL of acetone to 10 grams of chopped tomato sample in 50 mL conical tube. Homogenize the sample thoroughly to disrupt vegetable tissues. With blender: Weigh out an amount of chopped sample that provides a representative subsample of the tomatoes to be analyzed. Add the weighed sample to a blender with an acetone resistant cup. Add a volume of acetone (in mL) equal to twice the weight (in grams) of the tomatoes, e.g. 50 g tomatoes plus 100 mL acetone. Blend the mixture thoroughly to disrupt vegetable tissues. Transfer approximately 25 mL of the mixture to a 50 mL conical tube. Allow large particulates in the homogenate to settle to the bottom of the conical tube (at least five minutes). If tomato solids do not settle easily, centrifuge gently. Transfer approximately 4 mL of the acetone extract (upper layer) to a tube containing 1/4 teaspoon (or approx. 2.0 g) of sodium chloride. Cap the tube and vortex to mix thoroughly. Allow the aqueous and acetone phases to separate for about 5 minutes. ANALYSIS Carefully transfer 50 mL of the acetone phase (top layer) to a glass test tube and evaporate to dryness under nitrogen. Redissolve the residue in exactly 2.5 mL of the Sample Diluent. Analyze the diluted extract as the 'sample' according to package insert of the RaPID Assay.