Page 22 - 理化检验-化学分册2025年第三期

苏涵君，等：基于可见-近红外光谱技术快速检测水质酸度

[21] LI H D，LIANG Y Z，XU Q S，et al. Key wavelengths method for multivariate calibration[J]. Analytica Chimica
screening using competitive adaptive reweighted sampling Acta，2009，648（1）：77-84.

Rapid Detection of Water Acidity Based on Visible-Near
Infrared Spectrometry Technique

SU Hanjun, LI Lina *

(College of Mechanical Engineering and Automation, Huaqiao University, Xiamen 361021, China)
Abstract: In order to meet the requirements of rapid, accurate and continuous online detection of the water acidity
(pH), a method for rapid detection of the water acidity was proposed based on visible-near infrared spectrometry (Vis-NIRS)
technique in combination with chemometric methods. The original Vis-NIRS data were collected from 60 water solution samples
with varying acidities. These samples sets were split by Kennard-Stone (K-S) algorithm and sample set partitioning based
on joint X-Y distance (SPXY) algorithm. The original spectral data were pre-processed by the methods including Savitzky-Golay
(S-G) convolution smoothing, standard normal variate (SNV), first derivative (1D), second derivative (2D) and orthogonal signal
correction (OSC). Successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) algorithm were
used for characteristic wavelength screening. Different partial least squares (PLS) quantitative analysis models were established and
compared to determine the effect of the best model. As shown by the results, the SPXY algorithm for sample set partition, SNV
for spectral data pre-processing, and CARS for characteristic wavelength screening produced better performance for water acidity
PLS quantitative analysis model. The prediction set had a coefficient of determination of 0. 978 6 and a root mean square error of
0. 380 3, and the variable number of wavelengths involved in modeling was reduced from 2 860 to 45, greatly speeding up model
calculation. The proposed method could achieve rapid and accurate water acidity detection.
Keywords: visible-near infrared spectrometry (Vis-NIRS); water acidity; pre-processing; competitive adaptive reweighted
sampling algorithm; partial least squares （PLS）; qualitative analysis model

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