(1) Calibration of the electrode:a.

(1) Calibration of the electrode:
a. Calibration of electrode potential must be done each days or before analysis of sample bath.
b. Prepare four calibration standards using 100-mL volumetric flasks as follows:
- Standard A - 5.00 mL of sodium sulfide stock solution, 50 mL of SAOB and dilute to a total volume of 100 mL with water.
- Standard B - 1.00 mL of sodium sulfide stock solution, 50 mL of SAOB and dilute to a total volume of 100 mL with water.
- Standard C - 2.00 mL of calibration standard A, 50 mL of SAOB and dilute to a total volume of 100 mL with water.

Results (English) 3:

（1）电极的电极电位的
校准：校准必须每一天或之前的样品液分析。
准备四校准标准使用100毫升量瓶如下：
-标准- 5毫升的硫酸钠溶液，50毫升的硫化物抗氧化剂缓冲剂和稀的总体积100毫升的水。
标准B 1毫升的硫化钠溶液，50毫升的硫化物抗氧化剂缓冲剂和稀释至总体积100毫升水。
标准的C - 2毫升的校准标准，50毫升的硫化物抗氧化剂缓冲剂和稀释至总体积100毫升水。