Detection and Quantification of Alprazolam Added to Long Drinks by Near Infrared Spectroscopy and Chemometrics

Abstract

In the present work, a fast, relatively cheap, and green analytical strategy to identify and quantify the fraudulent (or voluntary) addition of a drug (alprazolam, the API of Xanax®) to an alcoholic drink of large consumption, namely gin and tonic, was developed using coupling near-infrared spectroscopy (NIR) and chemometrics. The approach used was both qualitative and quantitative as models were built that would allow for highlighting the presence of alprazolam with high accuracy, and to quantify its concentration with, in many cases, an acceptable error. Classification models built using partial least squares discriminant analysis (PLS-DA) allowed for identifying whether a drink was spiked or not with the drug, with a prediction accuracy in the validation phase often higher than 90%. On the other hand, calibration models established through the use of partial least squares (PLS) regression allowed for quantifying the drug added with errors of the order of 2–5 mg/L.

Discrimination of Robusta Amazônico coffee farmed by indigenous and non-indigenous people in Amazon: comparing benchtop and portable NIR using ComDim and duplex

“…At all stages, the PLS-DA classification threshold was established by applying linear discriminant analysis (LDA) on the predicted y values. 32 Finally, the spectral variables that most contributed to the dis-crimination were verified using the variable importance in the projection (VIP) indices. They were discussed based on previously published literature on NIR coffee analysis.…”

Rapid Determination of Geniposide and Baicalin in Lanqin Oral Solution by Near-Infrared Spectroscopy with Chemometric Algorithms during Alcohol Precipitation

“…Near-infrared (NIR) spectroscopy, with its features of being fast, nondestructive, and efficient, has been an ideal PAT tool in multiple fields since the end of the 20th century [9][10][11][12]. In most research, samples can be analyzed by NIRs without pretreatment [13][14][15].…”