[Rapid determination of nutrient components in lake sediments using near infrared spectroscopy]

The lake sediments record important environmental evolution information of lake in recent 100 years. However, a rapid and precise combination analytical method measuring nutrient components in lake sediments can not be established. The near infrared reflectance spectra (NIRS) of sediment coring samples were determined by near-infrared reflectance spectrometry. The respective near NIRS calibration models for predicting total carbon (TC), total nitrogen (TN), total organic carbon (TOC) and total phosphorus (TP) were built first in China using partial least squares (PLS) algorithm with six spectral pretreatment tools including first-order derivate, wavelet denoise, orthogonal signal correction (OSC), wavelet denoise combining orthogonal signal correction (OSC), first-order derivate combining orthogonal signal correction (OSC), and orthogonal signal correction (OSC) combining wavelet compression. The results showed that although NIR all calibration models can not well predict TOC, the first-order derivate combining OSC spectral calibration model had a good prediction for TC and TN, and for TP OSC spectral calibration model was good. The correlation coefficients between measuring values and predicted values in validation set for TC, TN and TP were 0.76, 0.87 and 0.81, respectively. RMSEP (Root mean square error of the prediction) for TC, TN and TP were 0.13%, 0.0082% and 0.012%, respectively. The study has an important significance of driving the domestic researches on spectroscopy characteristic of lake sediments and establishment of rapid analytical technique determining nutrient components of lake sediments.