GB/T 40175.3-2021Textiles—Methods of biochemical analysis—Part 3: Organophosphorus pesticide (enzyme-linked immunosorbent assay) (English PDF)

1 Scope

This document specifies the enzyme-linked immunosorbent assay for four organophosphorus pesticide residues, including parathion-methyl, DIMETHYL-P-NITROPHENYLPHOSPHATE, fenitrothion, and fenthion, in textiles.

This document applies to all kinds of textiles.

2 Normative references

The contents of the following documents constitute the indispensable clauses of this document through normative references in the text. For dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.

GB/T 6682, Water for analytical laboratory use - Specification and test methods

3 Terms and definitions

There are no terms and definitions that need to be defined in this document.

4 Principle

The organophosphorus pesticides in the sample and the organophosphorus pesticide antigens that have been coated on the ELISA plate in the kit competitively combine with the organophosphorus pesticide antibody; then, add the enzyme-labeled secondary antibody to form an antigen-primary antibody- […]

5 Reagents and materials

5.2 Washing liquid: Before use, add water to dilute the concentrated washing solution 5.1h) in a volume ratio of 1:9 (1 part of concentrated washing solution + 9 parts of water).

5.3 Color-developing agent: Before use, mix substrate A solution 5.1e) and substrate B solution 5.1f) in a volume ratio of 1:1.

5.4 N-hexane.

5.5 Ethyl acetate.

5.6 Methanol.

5.7 Phosphate buffer solution (0.01 mol/L): Dissolve 8.0 g of sodium chloride, 0.2 g of potassium chloride, 1.44 g of disodium hydrogen phosphate and 0.24 g of potassium dihydrogen phosphate in 800 mL of deionized water; use 0.01 mol/L hydrochloric acid to adjust the pH value of the solution to 7.4; add water to make the volume up to 1000 mL.

5.8 Methanol-phosphate buffer solution: Mix methanol and buffer solution (5.7) in a volume ratio of 1:4.

6 Equipment and utensils

6.1 Microplate reader: The wavelength is 450 nm.

6.2 Balance: The sensitivities are 0.1 g and 0.0001 g.

6.3 Micro adjustable pipette and matching tips: 50 µL, 100 µL, 1 000 µL.

6.4 Temperature-controllable ultrasonic bath: The working frequency is 40 kHz; the temperature control accuracy is ±5 °C.

6.5 Nitrogen-blowing instrument.

6.6 Oven: The temperature control accuracy is ±1 °C.

6.7 pH meter: It is equipped with glass electrode; the measurement accuracy is at least accurate to 0.1.

7 Test procedure

8 Calculation and expression of results

Calculate the average absorbance value of the standard solution and the sample solution respectively; calculate the relative absorbance value of the standard solution or the sample solution according to Formula (1).

Where: A - relative absorbance value;

B - average absorbance value of the series standard working solution or sample solution;

B0 - average absorbance value of 0 µg/L standard working solution.