Chlorine precision test strips are used to measure free chlorine, which is an important element of water. These test strips can be a useful tool for many reasons. They can help to prevent and avoid the bleaching out of paints, carpets, and other materials, and they can also be a valuable tool in testing for contaminants.
Chlorine precision test strips Bleaching out effect
For people who are looking to test the chlorine concentration in their swimming pools, there are two main methods that are available. First, there is the traditional dip test strip. It is a convenient tool for semi-quantitative analysis of substances. Nevertheless, its sensitivity is limited. In contrast, the lateral flow test can detect very low amounts of free chlorine.
However, the bleaching out effect can occur when high concentrations of chlorine or bromine are used. This can result in an inaccurate reading. The best indicator of this effect is a thin blue line separating the wet portion from the dry portion of the test strip.
A second method is to use a colorimetric technique. This test method is more accurate than the conventional dip test because the sample volume is larger. Another advantage of this technique is that no action is required during the analysis time.
There are a number of other tests that can be performed to test for various chlorine-related parameters. Some of them are colorimetric, titrimetric and OTO.
A free chlorine test using leuco crystal violet reached a detection limit of 0.2 ppm. Unfortunately, this is not as specific as the SA chromophore.
The colour intensity of the test is also influenced by the contact time. When two strips are stuck together, the results will be darker.
Chlorine precision test strips Measurement of free chlorine
Free chlorine test strips are convenient tools for semi-quantitative analysis of free chlorine. They are usually made of plastic, with a small chemical pad attached at the bottom.
Typically, free chlorine is measured using a chromophore, such as N,N-diethyl-p-phenylene-diamine (DPD). DPD is a colourless compound that changes to a pink-coloured colour when oxidising agents are present. It can also be combined with potassium iodide to detect combined chlorine.
Chlorine test strips are available for a wide range of parameters. However, they are not suitable for in-field testing. Hence, they should be calibrated in-situ at frequent intervals.
Chlorine tests can be used to measure free and total chlorine. The concentration of free chlorine is typically 0.2 to 4 PPM. This is the level recommended by the World Health Organization for disinfection purposes.
There are three methods of measuring free chlorine: manual visual measurements, amperometric sensors, and colorimetric test kits. Each method offers different advantages and disadvantages. For example, manual visual measurements are more sensitive to interference from the sample. But colorimetric test kits are cheaper and more accurate. Flow tests increase the sensitivity of chlorine measurements.
The DPD method can be used with lab or field instrumentation. However, it is susceptible to interference from other oxidants, such as chloramines, manganese, and chromium.
Chlorine precision test strips Common uses
Whether you are testing chlorine levels, pH, alkalinity, or redox parameters, test strips are an invaluable tool for semi-quantitative analysis. They change colour as they come into contact with analyte containing solutions.
The first line of the chart shows the intensity of the colour produced by a flow test in a small analyte solution. It varies depending on the length of the wick used. This is similar to the color change produced by a conventional colourimetric chlorine dip test strip.
For a flow test, 5 to 0.2 ppm free chlorine solutions were pumped through the reaction zone of a sample pad. In order to test the colour intensity of a high concentration of chlorine, a buffer was added. This increases the colour intensity. However, it also causes a reduction in the number of stripes that are visible.
Flow tests with commercial free chlorine test strips show detection limits that are not low enough. A hybrid flow test with a sample pad and wicking pads was performed to increase sensitivity.
Another redox dye, leuco crystal violet, was added to a SA solution. The SA ink was printed on cotton linters paper of 9 cm in length.
A flexible PP needle was held at 20 deg. A cellulose acetate solution was diluted with 0.3 to 5% (m/v) of SA solution.