When using the instrument for the first time, please use the standard sample for operational measurement. Only after the sample measurement is accurate (within ±5% error) can other water sample measurement be carried out.

Process of operation
Turn on the host power supply, press program key → Press OK key → Select CODL pre-, CODM pre-or CODH pre-(according to the concentration of the sample to be tested) → Press OK key to enter the zero calibration interface for preheating.

Open the power supply of the digester and select the COD digestion mode (165℃, 20мин);

When the sample COD was 0-150mg/L (CODL pre-), two low-range prefabricated reagent tubes were taken. Blank: suck 2mL distilled water into a cuvette;

Sample: Take 2mL sample in another cuvette;

When the sample COD is 150-1500mg/L (CODM pre-), two high-range prefabricated reagent tubes were taken. Blank: suck 2mL distilled water into a cuvette; Sample: Take 2mL sample in another cuvette;When the sample COD is between 1500-15000mg/L (CODH pre-), two high-range prefabricated reagent tubes were taken. Blank: suck 2mL distilled water into a cuvette; Sample: Take 1.8mL distilled water in another cuvette, and then add 0.2mL sample (or dilute the sample 10 пута, take 2mL);

Flow chart of water quality COD-N prefabricated reagent detection

Cover the above test tube and shake well (make sure the lid is tight, the test tube is hot, be careful to burn); When the digester buzzes and alarms, place the blank and sample in the digester with good temperature, cover with the protective cover, and press the confirm key to start digestion; When the digestion instrument beeping alarm again, то је, for the completion of digestion, take out the test tube cooling to room temperature (natural cooling, or natural cooling after 3-5 minutes of water cooling);

After the colorimetric tube is cooled to room temperature, wipe it clean. Under the corresponding items that have been preheated, put the blank into the instrument, press the zero key for zero calibration, then put it into the sample tube, press the measurement key for sample measurement, and the indicated value is the concentration value.

Напомене:
Built-in working curve, can be directly water sample measurement;

When measuring, the water sample can be roughly predicted first, and the over-range dilution sample can be measured;

When taking/adding samples and reagents, the pipette should be taken at the level of the concave liquid;

Pipettes or pipet tips for sample/reagent removal should not be used interchangeably to prevent reagent contamination;

Precipitation is a normal phenomenon;

Please ensure that the cover of the digestion tube is tightened before digestion;

Do not shake the digestion tube violently during wiping and measuring;

Make sure the water sample is colored before testing, but it must be clear.

Insert the blank digestion tube into the colorimetric groove for about 2-3 seconds and then press “Confirm” after the reading is stable;

It is normal for the data to fluctuate in a small range within a short time during sample measurement. (The average value is preferred as the final result)

Flow chart of water quality COD-N prefabricated reagent detection

Опис

The main interference factor of COD measurement is chloride ion, and the reagent comes with anti-chlorine interference 1000mg/L.

Samples cannot be placed for a period of time or repeated for test comparison at different time periods.

The measurement data should be within the corresponding range, if not, it can only roughly judge the water sample height, the need for accurate data should be selected

Low or high range or diluted determination, so that the measurement data in the corresponding range.

The colorimetric solution can not be placed in the digestion tube for a long time, and the digestion tube and its experimental tools should be cleaned in time.

Water sample pretreatment process and color matching process should be completed in a compact manner.

After the completion of the colorimetric solution can not be dumped at will, should be collected uniformly, centralized treatment.

If the digestion tube is scratched, please replace it in time to avoid affecting the accuracy of data.