GB/T 4324.17-2012Methods for chemical analysis of tungsten - Part 17: Determination of sodium content - Flame atomic absorption spectrometry (English PDF)

3.1

Ammonia (rho = 0.88g/mL), pure class distinctions.

3.2

Hydrogen peroxide (rho = 1.10g/mL), pure class distinctions.

3.3

cesium chloride solution (20g/L).

3.4 Sodium standard stock solution

Weigh 0.2542g advance by burning 550 °C 1h sodium chloride (wNaCl>=99.9%), placed in a quartz beaker

In, dissolved in water and transferred to 1000mL volumetric flask, dilute with water to volume, and mix. Stored in a plastic bottle, the solution containing 1mL

100µg sodium.

3.5 Sodium standard solution

Pipette 25.00mL sodium standard stock solution (3.4), placed in 500mL volumetric flask, dilute to the mark, mix uniform. Stored in a plastic bottle, containing 5µg solution 1mL sodium.

3.6 tungsten matrix

the composition of the sample is similar to the sodium content of not more than 0.0003%.

4.1

Atomic absorption spectrometer, with a sodium hollow cathode lamp.

Under optimum working conditions for those who can reach the following indicators can be used.

--- Characteristic concentration. in the solution was measured and consistent substrate solution, wherein the sodium concentration is not more than 0.01µg/mL.

--- Precision. standard solution with the highest concentration of 10 times the absorbance measurements, the standard deviation should not exceed 1.5% of the average absorbance;

The lowest concentration of standard solution used (instead of "zero concentration" standard solution) absorbance measured 10 times, and the standard deviation should not exceed the maximum

0.5% concentration of the standard average absorbance.

--- Linear curve. the curve according to concentration, is divided into five sections, the difference between the absorbance of the absorbance difference between the highest and the lowest segment of the segment

Ratio of not less than 0.7.