Chlorine dioxide content determination method

Abstract

The invention relates to a chlorine dioxide content determination method which adopts the previous four steps in a five-step iodometry method. The method is characterized in that the phosphate buffer solution is added in the step 1 and the step 3 until the pH value of the test solution is 7; 15-20 ml of potassium iodide solution is added in; and 2.5mol / L hydrochloric acid solution is added in the step 2 and the step 4 until the pH value is 2. The invention ensures that the added phosphate buffer solution meet the requirement of neutral pH and also ensures the potassium iodide solution sufficient so as to obtain sufficient reaction, and the pH value of the obtained solution is adjusted to 2 after the values A and C are measured; and except for the influence of the pH value of the solution to all the components thereof, the invention can determine the content of ClO2 in the chlorine dioxide disinfectant, is objective and accurate in measuring result and can reflect the contents of all the components in the chlorine dioxide disinfectant.

Description

technical field [0001] The invention relates to an improved chlorine dioxide content determination method, which can more accurately measure the ClO contained in the chlorine dioxide disinfectant 2 content. Background technique [0002] The five-step iodometric method is the method recommended in the American "Water and Wastewater Standard Test Method". The instrument used in this method is simple and can detect ClO at the same time 2 , ClO 2 - , Cl 2 , ClO 3- The four components are the key to evaluating the content in water or wastewater, and they are also ideal detection methods that cannot be realized by iodometric method and malonic acid iodometric method in the detection of water and wastewater components. The five-step iodometric method described in the 2002 edition of "Technical Specifications for Disinfection" is as follows: [0003] Step 1: Add 200ml of distilled water and 1ml of phosphate buffer to a 500ml iodine measuring bottle, draw 1.0-10.0ml of chlorin...

AI Technical Summary

Problems solved by technology

Otherwise, ClO 2 - Easily decomposes into unstable intermediates, resulting in titration steps without titration endpoints

However, the discussion and research of the five-step iodometric method for determining the content of chlorine dioxide in disinfectants stipulated in the 2002 edition of "Technical Specifications for Disinfection" requires adding 1ml of phosphate buffer solution, which cannot meet the nearly neutral pH requirement.

In addition, after measuring the A value and the C value, the pH value of the resulting solution must be adjusted to 2, but it should not be too small. However, the five-step iodometric method stipulated in the 2002 version of the "Disinfection Technical Specification" stipulates the discussion and discussion of the chlorine dioxide content of the disinfectant. Research, requiring the addition of 2.5ml hydrochloric acid, can not meet the requirement of PH value of 2, resulting in inaccurate measurement results