Ultraviolet Spectroscopic Detection of Nitrate and Nitrite in Seawater Simultaneously Based on Partial Least Squares.

ABSTRACT: A direct, reagent-free, ultraviolet spectroscopic method for the simultaneous determination of nitrate (NO3-), nitrite (NO2-), and salinity in seawater is presented. The method is based on measuring the absorption spectra of the raw seawater range of 200-300 nm, combined with partial least squares (PLS) regression for resolving the spectral overlapping of NO3-, NO2-, and sea salt (or salinity). The interference from chromophoric dissolved organic matter (CDOM) UV absorbance was reduced according to its exponential relationship between 275 and 295 nm. The results of the cross-validation of calibration and the prediction sets were used to select the number of factors (4 for NO3-, NO2-, and salinity) and to optimize the wavelength range (215-240 nm) with a 1 nm wavelength interval. The linear

SUBMITTER: Wang H 

PROVIDER: S-EPMC8234976 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature