Chemical Meaning of Near Infrared Spectra from a Portable Near Infrared Spectrometer for Various Plastic Wastes

Abstract

We examined NIR spectra obtained from various plastic wastes using a portable near infrared spectrometer; herein, we discuss chemical implications of spectral characteristics. A barcode spectrum derived from the second-order derivatives spectrum provides effective alternatives to discriminate plastic types. Principal component analysis, which is applied to barcode spectra, reveals characteristics and similarity of NIR spectra among plastic samples. Chemical structure of plastic samples reflects NIR spectra. Spectral differences can be explained with reference to whether the plastic has some functional group (aromatic CH, CO and Cl) or not.

Use of an NIR MEMS spectrophotometer and visible/NIR hyperspectral imaging systems to predict quality parameters of treated ground peppercorns

“…PC1 loadings were mainly influenced by absorption bands at 650 nm which may be attributed to chlorophyll (Seifert & Zude-Sasse, 2016). In the NIR-HSI spectra PC1 explained 93.2% of the variance with PC1 loadings mainly influenced by the absorption bands at 1216, 1342, 1412 and 1643 nm which may be attributed to the 2nd overtone of C-H bond stretching, the combination of -CH 2 , first overtone of -OH stretching in water and first overtone of aromatic -CH respectively (Kumagai et al, 2003;Rodriguez-Saona et al, 2017;Šašić & Ozaki, 2000).…”

“…Both technologies can be used for in-line control of multiple analytes in peppercorn processing. (Kumagai et al, 2003;Rodriguez-Saona et al, 2017;Šašić & Ozaki, 2000). Due to the larger spectral range of the NIR HSI system, better prediction models were developed compared to the NIR-MEMS systems.…”

Application of a Portable near Infrared Spectrometer for the Manufacturing of Noodle Products

“…3 We are also conducting a thorough investigation of the feasibility of the use of NIR and have attained some positive results. [4][5][6] In this study we intend to produce a practical use for NIR, based on a series of our developments using a portable NIR instrument. This practical use hinges not only on its feasibility at the premises where Inaniwa Udon is manu-factured, but also on empirical chemical interpretation of NIR spectra.…”

Material identification and imaging of microplastics when dispersed in water using near-infrared light toward combination with a flow cell

“…For example, the peak at λ = 1680 nm was observed for PS and PMMA, and the peak at λ = 1730 nm was observed for PE and PP. 28,29) The spectrum shapes of each material were notably different in this wavelength range, and they are thus expected to be effective when used for material identification. 17) We hereafter denote the spectrum data of the four materials as reference data.…”

“…The correlation coefficient was calculated to evaluate the similarities in spectrum shapes between the measured data and reference data. 12,14,28) We took the reference data at each water thickness condition. The material was identified when the highest coefficient value among the four plastic materials was higher than the threshold value 0.7.…”