T/NAASS 042-2022 Active Group standards

T/NAASS 042-2022 Determination of Chloride Ion Concentration in Fresh Milk Using Ion Chromatography

Publish Date: 2022-12-28 Implement Date: 2023-01-31 For services related to genuine standard inquiry, procurement, translation, and other related services in China, please Contact Us

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Basic Information

Standard Code: T/NAASS 042-2022

Standard Type: Group standards

Standard Status: Active

is_force_gb: no

CCS Name: -

ICS Name: Animal husbandry and breeding

Publish Date: 2022-12-28

Implement Date: 2023-01-31

Scope

Scope: This document specifies the ion chromatography method for determining the chloride ion content in raw milk. This document is applicable to the determination of chloride ion content in raw milk; Main technical content: The principle is that the sample is diluted, acetonitrile is used to precipitate proteins, then the sample passes through a degreasing column for purification. Based on the different affinity of various ions for the ion chromatography column, the ions are separated and detected by an electrical conductivity detector using an external standard method. Unless otherwise specified, all reagents used in this method are of analytical grade, and the water used meets the requirements of GB/T 6682 for Class I water. Reagents and materials: Unless otherwise specified, all reagents used in this method are of analytical grade. Acetonitrile (CH3CN): chromatographically pure. Methanol (CH3ON): chromatographically pure. 40 mmol/L potassium hydroxide solution: Weigh 2.24 g of potassium hydroxide and dilute it to 1000 mL with water. Chloride ion standard solution (ρ(Cl) = 1000 mg/L, water as the matrix): Accurately transfer 0, 50 μL, 100 μL, 250 μL, 500 μL, 750 μL, and 1000 μL of the chloride ion standard solution (4.1.4) into a 50 mL volumetric flask and mix well with water. The resulting chloride ion standard working solutions have concentrations of 0, 1.0, 2.0, 5.0, 10.0, 15.0, and 20.0 μg/mL. Store at 0–4 °C and have a validity period of 1 month. Materials: Filter membrane: 0.22 μm. RP column (1.0 mL), or a comparable pre-treatment column capable of removing organic substances. Activate the column with 5 mL of methanol and 10 mL of water in turn and allow it to stand for 30 minutes before use. Instrumentation and equipment: Ion chromatograph equipped with an electrical conductivity detector and suppressor. Ultrasonic cleaner. Analytical balance: with a sensitivity of 0.01 g. Refrigerator with a 4 °C refrigeration compartment.