[Simultaneous analysis of trace Cu2+, Ca2+ and Zn2+ in surface water from Yangtze and Jialing River with Kalman filter-spectrophotometry].

1-(2-pyridine azo)-2-naphthol(PAN) is one of color reagent to determine the concentration of many trace metal ions. The analyzing conditions of PAN chelating reaction with three metal ions such as Cu2+, Cd2+ and Zn2+, the spectral properties at maximum absorption wavelength of these chelate compounds, pH effect and reaction time and so on were studied. Combining with Kalman filter algorithm and spectrophotometric simultaneously determining on-line technology the water samples containing the three metal ion compounds chelated with PAN from our laboratory, Yangtze River and Jialing River were analyzed quantitatively under optimal analysis condition, and the recovery is between 90.