Abstract:

Sulfate and nitrate as important components of atmospheric particulates water-soluble components have important effects on climate and human health, thus realization of the fast quantitative detection has important scientific significance. The one-component aqueous solution of sulfate and nitrate were analyzed by attenuated total reflection Fourier transform infrared spectrum (FTIR/ATR). The result shows that the linear relation is good and the correlation coefficients are 0.9982 and 0.9997, respectively. The mixture of sulfate and nitrate was prepared using the orthogonal experiment design, the quantitative analyses of sulfate and nitrate were carried out by one-dimensional linear regression and multivariate calibration based on partial least squares (PLS) model respectively. The result shows that the prediction accuracy of sulfate by one-dimensional linear regression is better than the prediction accuracy of sulfate by multivariate calibration and the average relative error of predictive value is 2.6%, the prediction accuracy of nitrate by multivariate calibration is better than the prediction accuracy of sulfate by one-dimensional linear regression and the average relative error of predictive value is 2.31%. The method is rapid and simple and it is the foundation of the quantitative analysis of sulfate and nitrate in aerosol aqueous solution at the same time.

Key words: sulfate, nitrate, FTIR-ATR spectroscopy, partial least squares