Abstract

A portable Raman system with an immersion fiber optic probe was assessed for point-of-collection screening for the presence of adulterants in liquid milk. N-rich adulterants and sucrose were measured in this proof-of-concept demonstration. Reproducibility, limit of detection range and other figures of merit such as specificity, sensitivity, ratio of predicted to standard deviation, standard error of prediction and root mean squared error for cross validation were determined from partial least squares (PLS) and partial least squares with discriminant analysis (PLS-DA) calibrations of milk mixtures containing 50–1000 ppm (parts per million) of melamine, ammonium sulphate, Dicyandiamide, urea and sucrose. The spectra were recorded by immersing the fiber optic probe directly in the milk solutions. Despite the high scattering background which was easily and reliably estimated and subtracted, the reproducibility for four N-rich compounds averaged to 11% residual standard deviation (RSD) and to 5% RSD for sucrose. PLS calibration models predicted the concentrations of separate validation sets with standard errors of prediction of between 44 and 76 ppm for the four N-rich compounds and 0.17% for sucrose. The sensitivity and specificity of the PLS-DA calibration were 92% and 89%, respectively. The study shows promise for use of portable mini Raman systems for routine rapid point-of-collection screening of liquid milk for the presence of adulterants, without the need for sample preparation or addition of chemicals.

© 2016 The Author(s)

Terahertz spectroscopy detection of zinc citrate in flour and milk powder mixtures

Ziyu Song, Min Liao, Dongxiong Ling, Changshui Chen, and Dongshan Wei
Appl. Opt. 61(25) 7443-7448 (2022)

Demonstrating the application of Raman spectroscopy together with chemometric technique for screening of asthma disease

Rahat Ullah, Saranjam Khan, Fizah Farman, Muhammad Bilal, Christoph Krafft, and Shaheen Shahzad
Biomed. Opt. Express 10(2) 600-609 (2019)

Raman spectroscopy combined with a support vector machine for differentiating between feeding male and female infants mother’s milk

Rahat Ullah, Saranjam Khan, Samina Javaid, Hina Ali, Muhammad Bilal, and Muhammad Saleem
Biomed. Opt. Express 9(2) 844-851 (2018)

Miniaturized optical fiber probe for prostate cancer screening

Antonio Iele, Armando Ricciardi, Claudia Pecorella, Andrea Cirillo, Fanny Ficuciello, Bruno Siciliano, Roberto La Rocca, Vincenzo Mirone, Marco Consales, and Andrea Cusano
Biomed. Opt. Express 12(9) 5691-5703 (2021)

Identification and quantification of vegetable oil adulteration with waste frying oil by laser-induced fluorescence spectroscopy

Shiguo Hao, Lian Zhu, Ronglong Sui, Mengling Zuo, Ningning Luo, Jiulin Shi, Weiwei Zhang, Xingdao He, and Zhongping Chen
OSA Continuum 2(4) 1148-1154 (2019)