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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.