Determination of metals in natural waters by spectrophotometry in combination with PLS algorithm

Abstract

Currently determination of metals in natural waters is carried out by atomic absorption spectroscopy ( AAS ). The main disadvantage of the existing methods is the time-consuming sample preparation. The determination of metals by spectrophotometry using non selective piridilazorezortsin reagent ( PAR ) and the algorithm of projection to latent structures ( PLS ) was proposed to improve the rapidity of analysis. Preparation of natural water to the analysis comprises the neutralizing of pre-conserved and filtered water sample followed by adding the reagent and buffer solutions. Absorption spectra were recorded in the range 350-600 nm. Spectra of the samples were investigated by the method of principal components. It is shown that the spectra are not homogeneous and they form several groups. The most informative part of the spectrum is 400-520 nm. For the first time PLS-calibration was built on the spectra of real water samples using the data obtained by AAS. This approach allows us to take into account the influence of other components and to determine simultaneously 4 metals (Fe, Cu, Mn, Zn) in natural waters with errors of 1-5% rel. and the relative standard deviation of 0.01 to 0.06 that is comparable to the method of AAS in accuracy. The minimal sample preparation significantly reduces the analysis time and labor intensity. Keywords : spectrophotometric analysis, method of projection to latent structures, natural waters (Russian) DOI: http://dx.doi.org/10.15826/analitika.2014.18.4.007 P.A. B uriukina, I.V. Vlasova, K.A. Spiridonova Dostoevsky Omsk State University , Omsk, Russian Federation REFERENCES 1. GOST 4388-72. Voda pit’evaia. Metody opredeleniia massovoi kontsentratsii medi [State Standard 4388-72. Drinking water. Methods for determination of the mass concentration of copper]. Moscow, 1972. 9 p. (in Russian). 2. PND F 14.1:2.44-96. 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