title: Improving the sensitivity of NIR spectroscopy with an enrichment technique: determining a trace analyte of ethyl carbamate.
abstract: An exploration was made to develop a determination method of a low-concentration analyte by NIR spectroscopy. An absorber, silica gel was employed to extract and enrich a low-concentration analyte of ethyl carbamate. The solid absorber with the enriched analyte was measured by NIR spectroscopy in the range of 800 - 2500 nm. Afterwards, PLS regression was performed between the NIR spectra and the concentrations of the analyte for quantitative analysis of the low-concentration analyte. The spectra of 20 solid samples of analyte-absorbed silica gel showed a good correlation with the concentrations of ethyl carbamate in the samples. A leave-one-out cross validation was applied to evaluate the prediction ability of PLS models built with the full spectra, spectra in the region of 1920 - 1970 nm and the region of 2250 - 2430 nm, respectively. The values of the root-mean-square error of the cross validation (RMSECV) were about 0.1 mg L(-1) (0.1 ppm).
authors.affiliation: Center of Analysis and Test, East China University of Science and Technology, Shanghai, China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Wei
authors.forename: Zixia
authors.initials: Z
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Yiping
authors.initials: Y
authors.lastname: Du