Chemical analysis

ChemScan manufactures a range of single and multi-parameter online process chemical analysers to measure chemicals at municipal drinking water treatment plants and municipal wastewater treatment plants or in an industrial process involving liquids.

The process analyser can be thought of as an online ultraviolet-visible spectrometer, designed to collect the full absorbance signature of a sample at 256 wavelengths. This is accomplished by drawing a volume of sample into a flow cell, transmitting known intensities of light through the sample and detecting the intensity of light that remains at each wavelength in the range.

The standard instrument detects light from 200 to 450 nm. Special versions of the instrument can increase the number of wavelengths and extend the range through the visible spectrum.

The instrument applies pattern recognition techniques to the full absorbance signature of a sample in order to detect multiple chemical parameters using a single analyser. A manifold system is used to monitor multiple sample points in a process.

The unit can detect any chemical substance that absorbs light in the ultraviolet or visible wavelength range. Absorbance in this wavelength range is typically associated with the bond structures of specific molecules. Ions of nutrients, ions of heavy metals that form coordination compounds in water, unsaturated (double- or triple-bonded) hydrocarbons and aromatics are usually good candidates for analysis using ultraviolet or visible spectrometry.

Chemicals that possess natural absorbance characteristics can be detected directly using primary absorbance techniques. Chemicals that do not possess natural absorbance require the assistance of a reagent for indirect detection using secondary analysis techniques.

ChemScan has developed many primary and secondary analysis methods that take advantage of the multiple wavelength detection capability to simplify the analysis. It can also perform multiple primary and secondary analyses of a sample.

All analysers are designed to perform automatic zeroing and cleaning. Deionised water is used as the zero standard, while dilute acid or bleach is the typical cleaning solution. Zero and clean intervals are operator selectable from the analyser menu.