Bromate Analysis System
Incorporating the LC-20Ai solvent delivery pump for inert LC reduces baseline noise. The LC-20Ai features an improved solvent delivery control mechanism as the reaction reagent delivery pump of the bromate analysis system. This enables even higher-sensitivity bromate analysis.
The SIL-20AC autosampler features a pump measuring method and a total volume injection method for significantly improved injection accuracy. It also has an inert tubing kit in order to reduce the absorption and decomposition of bromate caused by contact with metallic parts.
The water quality standard specifies a maximum level of 10 mg/L as the criteria for total nitrate and nitrite ion content, but the target value for nitrite content as a water quality management item is 0.05 mg/L maximum (provisional). In this case, with a quantitation range lower concentration limit of 0.005 mg/L, the quantitation value will be inaccurate due to the influence on the nitrite ion peak by the tailing peak of the of the carbonate ion which elutes from the tap water immediately before the nitrite ion. Therefore, utilizing the ultraviolet absorption property of the nitrite ion, a simple UV detector was used for measurement of the nitrite ion. Use of a UV detector avoids any influence from the carbonate ion since it does not exhibit UV absorption, allowing selective detection of the nitrite ion.
Fig. 3 shows an example of conductivity detection of tap water spiked with ethylenediamine and the standard mixture of ions (see Table 2 for spike quantities). Fig. 4 shows an example of absorbance detection. The nitrite ion was analyzed with high sensitivity and good accuracy without influence from neighboring peaks, and with excellent peak response due to the advantage of using a UV detector.