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A rapid analytical and quantitative evaluation of formaldehyde in squid based on Tri-step IR and partial least squares (PLS)
- Gu, Dong-Chen, Zou, Meng-Jun, Guo, Xiao-Xi, Yu, Pan, Lin, Zhi-Wei, Hu, Tu, Wu, Ya-Fen, Liu, Yuan, Gan, Jian-Hong, Sun, Su-Qin, Wang, Xi-Chang, Xu, Chang-Hua
- Food chemistry 2017 v.229 pp. 458-463
- formaldehyde, freshness, glycogen, high performance liquid chromatography, infrared spectroscopy, least squares, models, proteins, public health, quantitative analysis, screening, squid
- Formaldehyde abuse for retaining squid freshness is detrimental to public health. The aim is to establish a rapid and quantitative detection method of formaldehyde in squid for screening massive samples. A linear relationship between formaldehyde concentration in squid and formaldehyde concentration in squid soaked water was observed using HPLC. Chemical profile variances of squids were rapidly analyzed by Tri-step infrared spectroscopy. Specifically, with increasing formaldehyde concentration, peak intensities of 2927cm−1 (vas(CH2)), 1081cm−1 (glycogen), 1631cm−1 (β-sheet proteins) decreased while 1655cm−1 (α-helix proteins) increased. Spectral curve-fitting results further disclosed that β-sheet proteins were transformed to α-helix and β-turn conformations. Furthermore, a quantitative prediction model based on IR spectra was established by PLS (R2, 0.9787; RMSEC, 5.51). The developed method was applicable for rapid (c.a. 5min) and quantitative analysis of formaldehyde in squids with LOD of 15mg/kg.