Chemometric Approach to a Rapid Attenuated Total Reflection Fourier Transform Infrared Analysis of Complex Heroin-Based Mixtures

Abstract

Heroin is one of the most frequently seized drugs in the South-Eastern Europe. Due to the position in the Balkan route, the Republic of Serbia keeps important role in suppression of the trafficking of heroin for domestic and foreign illegal market. This research is aimed to provide a good scientific approach in the field of seized heroin analysis. Two different forms of heroin are present in the illegal market, mostly in mixtures with typical "cutting" agents: caffeine, paracetamol and sugars. It was observed that the quantity of pure heroin in seized samples slightly increases from year to year. The aim of this study was to produce a reliable and fast procedure for classification of illicit heroin samples and determination of the concentration range of heroin in the samples. For that purpose the Fourier Transformed Infrared Spectroscopy (ATR technique) was used and combined with chemometric methods (PCA, CA, PLS). Principal components analysis (PCA), as an unsupervised model, was used for exploratory purposes, to identify trends, similarities and differences between samples, by reducing the dimensionality of the data. The cluster classification of examined samples turned out to be extremely useful to evaluate the possibilities of the ATR-FTIR technique to classify the samples appropriately into the patterns, the constituted clusters. Additionally PLS was the suitable method for the purpose of determination of the heroin hydrochloride concentration range in examined samples. It is proved that the joined application of spectroscopy and chemometrics can be extremely convenient and useful for forensic and drugs control laboratories.

Interpol Review of Drug Analysis 2019-2022

“…2019 DART-HRMS followed by multivariate statistical analysis to infer the sources of heroin samples seized in China [ 134 ]; electrochemical strategies to detect heroin in street samples without the use of electrode modifications [ 135 ]; 2020 HPLC-MS/MS method for detection and quantification of the main alkaloids in heroin [ 136 ]; 2021 development of an HPLC-MS/MS method for the quantification of the main alkaloids in heroin [ 137 ]; ATR FT-IR method for classification and determination of the concentration range of illicit heroin in seized samples [ 138 ].…”

Full Characterisation of Heroin Samples Using Infrared Spectroscopy and Multivariate Calibration

“…However, heroin is rarely encountered as such and often contains many impurities and adulterants, resulting in colours ranging from white to dark brown. The wide variety in purity poses the greatest risk when using heroin, due to the difficulty in dosing and thus the risk of (lethal) overdoses [ 12 , 13 ]. For illustration, a Serbian study showed a variety in purity in their sample set from 1.7 to 58.8% w / w [ 13 ].…”

“…The wide variety in purity poses the greatest risk when using heroin, due to the difficulty in dosing and thus the risk of (lethal) overdoses [ 12 , 13 ]. For illustration, a Serbian study showed a variety in purity in their sample set from 1.7 to 58.8% w / w [ 13 ]. Diluents that are often encountered in these samples are inert powders like chalk, flour, talcum powder and glucose, but also pharmacological active compounds like acetaminophen and caffeine [ 12 , 13 ].…”

“…For illustration, a Serbian study showed a variety in purity in their sample set from 1.7 to 58.8% w / w [ 13 ]. Diluents that are often encountered in these samples are inert powders like chalk, flour, talcum powder and glucose, but also pharmacological active compounds like acetaminophen and caffeine [ 12 , 13 ]. A whole range of impurities might be present, originating from the production process.…”

“…In general, heroin samples are analyzed using gas or liquid chromatography paired with mass spectrometry (GC/LC–MS), possibly followed by other techniques for purity determination or quantification of certain adulterants [ 8 , 9 ]. From the techniques available at the majority of the drug checking services, infrared spectroscopy (IR) shows the highest potential, especially when it is used together with multivariate calibration techniques [ 12 , 13 , 19 , 20 , 21 , 22 , 23 ]. The combination of infrared spectroscopy, both mid- and near IR, and multivariate calibration was already applied in a plethora of fields, ranging from illegal medicines [ 24 ] and cosmetics [ 25 ], through e-liquids [ 26 , 27 ] and food analysis [ 28 , 29 , 30 ] to the analysis of illicit drug samples.…”