Methylene blue spectrophotometric method for determination of quality verification report sulfide

First, the method of verifying step

1.1 Reagent preparation: preparation according to GB / T16489-1996.

1.2 Draw standard curve: Draw predetermined GB / T16489-1996 Procedure.

1.3 Precision Experiment: Take a standard high concentration of sodium sulfide, medium and low water samples three gradients, measured parallel to the respective six, to calculate the relative standard deviation of six samples for each concentration.

1.4 Accuracy test: (Department of Environmental Protection Institute of standard samples, reference material number 205528) with a sulfide standard sample tested. Of 10mL standard substance solution to a predetermined amount of zinc acetate added sodium / B mixed solution of pure water and 250ml

Brown volumetric flask to volume with pure water, immediately after mixing. After samples were taken the standard solution was diluted with 15mL

6 parallel samples were made, in accordance with GB / T16489-1996 experiment Experimental Procedures. Calculate the standard sample concentration, and determination

Whether the error allowable range.

1.5 Determination of sample: Press GB / T16489-1996 measurement, the following steps:

1.5.1 nitrogen through the airtightness detection device, off the air supply.

1.5.2 Take 20ml zinc acetate - sodium acetate in 100ml colorimetric tube.

1.5.3 certain volume of standard solution was added sodium sulfide three-neck flask, add 5ml antioxidant solution, oxygen-free water was added to a total volume of about 200ml. Fitted with nitrogen inlet, nitrogen gas is turned on at a rate of 200 ~ 300ml / min after pre-blowing 2 ~ 3min,

Off the air supply.

1.5.4 water bath temperature was raised to 60 ℃.

1.5.5 Open piston graduated tube with acid, phosphoric acid solution was added to the flask 10ml, adding an acid to close the calibration tube of the piston.

1.5.6 nitrogen turned on, a flow of 300ml / min continuously blowing 30min, to / min flow rate 400ml blowing 5min, in time to make the last remaining hydrogen sulfide gas in the device. Rinse with a small amount of water absorption liquid conduit inserted, removed cuvette turning it off, water was added to about 60ml, was slowly added 10 ml of N, N-dimethyl-p-phenylenediamine solution, immediate stoppering, iron sulfate and then addition of 1ml ammonium solution, sufficiently shaken and immediately Mesa, placed 10min.

1.5.7 The solution was washed with water volume to 100ml, shake. 1cm cuvette water as reference, measured Jinan Shing Electronic Technology Co., Ltd. at a wavelength of 665nm method verification report

Absorbance. The measured absorbance after deducting the value of the absorbance of the blank test, isolated sulfide content in the calibration curve.

Second, the method of validation results

The linear range of the standard curve and 2.1

Third, pay attention

1 during the test, the oxygen-free water are deionized water, oxygen and nitrogen can be blown off.

2 Standard solution of sodium sulfide to be present with current standard, immediately after the calibration according to the standard dilution and fixed using standard sodium sulfide

liquid.

3 airtightness test and inspect the entire piping prior to avoid leakage.

4 during the test to ensure a uniform flow of nitrogen.

5 color, inclusive of two reagents added sulfuric acid, should be added slowly along the wall, and stopper immediately to avoid loss of hydrogen sulphide escaping.

Note that mass 6 nitrogen, the nitrogen purity ≥99.999%.

Jinan Shing Electronic Technology Co., Ltd. Method Validation Report

Conclusions

Our instruments meet the "Water quality Determination of sulfide - Methylene blue spectrophotometric method" (GB / T16489-1996) testing requirements.

experimenter:


Reviewed by:


Approved by:


Approval Date: The date