GB/T 38789-2020Oral care and cleansing products—Determination of 10 elements in toothpaste—Inductively coupled plasma mass spectrometry (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

1 Scope

This standard specifies the inductive coupling plasma of 10 metal elements of lead, arsenic, mercury, selenium, iron, copper, manganese, cadmium, chromium and titanium in toothpaste and mouthwash Principles of measuring methods of progeny mass spectrometry, reagents or materials, instruments and equipment, instruments and equipment, test data processing, detection limit and quantification limit and precision.

This standard applies to the determination of 10 elements in lead, arsenic, mercury, selenium, iron, copper, manganese, cadmium, chromium and titanium in toothpaste.

2 Normative references

The following documents are essential for the application of this document. For dated references, only the dated version applies to this document. For the cited documents without date, the latest version (including all amendments) applies to this document.

GB/T 33087 High purity water specification and test method for instrument analysis

3 Principle

After digestion, the sample is measured by inductively coupled plasma mass spectrometer, characterized by the element mass-to-charge ratio (m/z), using external standard method The intensity ratio of the mass spectrometry signal of the element to the mass signal of the internal standard element is proportional to the concentration of the element to be measured for quantitative analysis.

4 Reagents or materials

Unless otherwise stated, the reagents used are of analytical purity, and the water used is high purity water in accordance with GB/T 33087.

4.2 30% hydrogen peroxide

Excellent grade pure.

4.3 Hydrofluoric acid

Excellent grade pure.

4.4 Nitric acid solution (5%, volume fraction)

Accurately measure 50mL of nitric acid (see 4.1), slowly add 950mL of water, and mix well.

4.5 Element standard stock solutions (each 1000 mg/L)

Lead, arsenic, mercury, selenium, iron, copper, manganese, cadmium, chromium, and titanium use standard substance certificates Single or multi-element standard stock solution.

4.6 Standard stock solution of internal standard elements (each 1000mg/L)

Scandium, germanium, indium, rhodium, rhenium, bismuth, etc. use single elements with standard substance certificates Or multi-element standard stock solution.

4.7 Mixed standard working solution

Pipette appropriate amount of elemental standard stock solution (see 4.5) and dilute with nitric acid solution (see 4.4) to make a mixed standard For the quasi-working solution series, see the mass concentration of each element in Appendix A A1.

Note: According to the mass concentration level of the element in the sample digestion solution, appropriately adjust the mass concentration range of each element in the standard series.

4.8 Internal standard working solution

Take appropriate amount of internal standard element stock solution (see 4.6), prepare a suitable concentration of internal standard working solution with nitric acid solution (see 4.4) For the reference concentration of the liquid and internal standard elements, see Appendix A.2.

Note: The internal standard solution can be added manually in the preparation of mixed standard working solution and sample digestion solution, or it can be added online by the instrument.

5 Instruments