How to choose the correct COD analyzer?

How to choose the correct COD analyzer? The traditional COD measuring instrument method is time-consuming and has large operating errors, and the COD measuring device appears with the development of science and technology
.

There are various types of COD analyzers on the market today, so how do you choose a COD analyzer? 1.
The detection principle of the COD analyzer First of all, it is necessary to judge whether it is tested according to the standard
.

The standard is "Determination of Water Chemical Oxygen Demand Rapid Digestion Spectrophotometry (HJT399-2007)"
.

§ Equipment technical parameters a.
High and low range Some commercial COD meters are not divided into high frequency and low frequency files, they are used for high frequency detection wavelength detection
.

Therefore, the detection of water samples with low COD values ​​does not meet the standard requirements, and there are large errors and inaccuracies
.

In the standard, when the sample COD value is 15 - 250 mg L, the total absorbance of the two chromium ions, hexavalent chromium and trivalent chromium, at a wavelength of 440 nm ± 20 nm is specified to be measured
.

When the COD value in the sample was 100 to 1000 mg L, the absorbance of trivalent chromium ions generated by reduction at 600 nm±20 nm was measured
.

Of course, the COD testing equipment currently on the market is basically based on testing standards
.

§ Measurement range Due to various factors or design purposes, the detection range of the instrument is different, and the instrument can choose the correct measurement range according to the basic conditions of the required water sample
.

For example, different measuring instruments are designed for different needs: the detection range is 0-2000 mg and 0-10000 mg respectively
.

C.
The three technical indicators of accuracy, repeatability and optical stability can be used to evaluate tool performance and measurement error
.

The higher the precision, the smaller the indication error, the more accurate the measurement of the instrument, the smaller the deviation relative to the standard, and the better the repeatability of the instrument
.

In addition, the light source used in the instrument is also critical.
COD analyzers use a light source
.

Cold light sources commonly used by tools
.

Of course, it will be slightly more expensive, but the instrument is optically stabilized
.

§ Function In order to meet different requirements, the COD analyzer adds data storage, printing and USB interface to transfer data to the computer
.

To meet external requirements, it is designed with portable tools, large built-in battery capacity,
etc.

This bills factory reset and other features
.

Different functions can be selected according to your needs and estimates
.

 The above is the relevant introduction about the selection of COD analyzer.
I believe that everyone has a corresponding understanding of this after reading it.
When choosing, you should choose according to your own needs.
I hope it will help you
.