The Manufacture And Application Of A Portable Colorimeter

Turbidity is an important specification for the evaluation of water quality. How to improve the measurement accuracy is one of the main researching objects of turbidimeter. The efforts to improve the accuracy and stability during the design of turbidimeter are described in this paper. For this purpose, two turbidimeters are designed, which is based on two measuring fundamentals of turbidity—scattering light method and transmission light method, then the measurement experiments are done.The trace Cr(Ⅵ) is usually determined by colorimetry using diphenylcarbazine, which is not able to be dissolved in water. In this paper, the diphenylcarbazine citrate was synthesized and the solubility of the diphenylcarbazine citrate was improved notably. Therefore, a new rapid spectrometry for Cr(Ⅵ)determination in situ was established using the reagent newly synthesized and the portable photometer made in our lab. In the weak acid medium, diphenylcarbazine citrate is colored by Cr(Ⅵ) to form a magenta-colored complex as the diphenylcarbazine usually does. The molar absorptivity for Cr(Ⅵ) is 3.32×104L·mol-1·cm-1 at 540nm, and the Beer's law is obeyed in the range of0.03～2.00mg／L. All the analysis can be completed within 3 minutes. Contents of Cr(Ⅵ) in electroplating waste water and industrial waste water were determined in situ , and all the results were satisfactory.During the past 20 years, evaporative light-scattering detection (ELSD) has moved into the mainstream of detection choices for liquid chromatography (LC) separation. The evaporative light scattering detector is a preferred detector for some applications — for example, carbohydrate, lipid, or polymer analysis — but it also is an attractive complement to spectroscopic detectors for a host of other applications. ELSD offers freedom from some of the limitations of spectroscopic detection because it is not limited to compounds that contain UV-absorbing chromophores, and it is immune to mobile-phase variations and gradient baseline shifting. And the fundamental and application of ELSD are detailed introduced in this paper.