MATRIX: Citrus Juice: 100% juice (natural strength) or juice concentrate
LIMIT OF DETECTION: 37 ppb in 100% juices and approximately 30 ppb in juice concentrates.
RANGE OF DETECTION: 37 ppb to 15 ppm in 100% juices and approximately 30 ppb to 12 ppm in
MATERIALS: Aldicarb RaPID Assay, Kit and Sample Diluent. Reagents: methanol (pesticide grade) and distilled or deionized water. Equipment: qualitative filter paper (coarse), scintillation vials, stir bars, magnetic stir plate, tabletop centrifuge, 15 mL centrifuge tubes and serological pipets.
SAMPLE TREATMENT: 100% fruit juices: Filter the juice through the qualitative filter paper to remove the pulp. Hold the filtrate and proceed to the analysis step below. Juice concentrates: Weigh 2 grams of the concentrate into a scintillation vial. Add 4 mL of methanol to the vial with a serological pipet. Add a stir bar to the vial, cap and stir on a magnetic stir plate for 10 minutes. Pour the mixture into a centrifuge tube and centrifuge at high speed for 5 minutes. Reserve the supernatant and proceed to the analysis step below.
ANALYSIS AND INTERPRETATION: 100% fruit juices: Dilute an aliquot of the juice filtrate 1:150 in Aldicarb Sample Diluent (0.1 mL filtrate + 14.9 mL diluent). Analyze the diluted extract as the 'sample' according to the package insert for the Aldicarb RaPID Assay. Calculate the aldicarb concentration in the original fruit juice sample by multiplying the assay result (ppb) by 150. Juice concentrates: Dilute an aliquot of the methanol supernatant 1:50 in Aldicarb Sample Diluent (0.1 mL filtrate + 4.9 mL diluent). Analyze the diluted supernatant as the 'sample' according to the package insert for the Aldicarb RaPID Assay. The water content of commercially available orange juice concentrate is estimated by the US FDA at 0.58 mL water per gram of concentrate weight.