SN/T 5104-2019 in English

Standard Technical Background

This standard is an industry standard for entry-exit inspection and quarantine. Aiming at the demand for port drinking water safety supervision, this standard uses anodic stripping voltammetry to establish a simultaneous detection scheme for six heavy metals. Compared with the traditional atomic absorption method, this method has the advantages of low detection limit (0.01mg/L), simple pretreatment and simultaneous analysis of multiple elements.

Core Detection Principle

Key instrument configuration

The standard requires the use of the NanoTek2000 voltammetric analysis system, with a three-electrode system:

• Working electrode: Φ10mm glassy carbon electrode
• Reference electrode: Ag/AgCl (3mol/L KCl)
• Auxiliary electrode: Platinum wire electrode

Key points for standard implementation

Quality control requirements

Preparation of standard solution

Key reagents must be high-grade pure Specifications:

1. Zinc standard solution: 1.000g high-purity zinc powder is dissolved in (1+99)HNO₃
2. Mercury standard solution: 0.1354g HgCl₂ is dissolved in (1+19)HNO₃ and K₂Cr₂O₇ stabilizer is added

Technology Evolution Analysis

Compared with GB/T 5750 series drinking water standards, this standard has the following features:

• The detection limit is reduced by 50% (lead is reduced from 0.02mg/L to 0.01mg/L)
• The mercury film electrode technology is introduced to improve the sensitivity of arsenic detection
• The standard addition method is used to eliminate matrix interference