Malays. J. Anal. Sci. Volume 30 Number 2 (2026): 1733

Research Article

Discrimination and source correspondence of cling film using ATR-FTIR spectroscopy and chemometrics techniques

Muhammad Naeim Mohamad Asri^1*, and Sathyasri Mohagana Sundaram²

¹Faculty of Science and Technology, Universiti Sains Islam Malaysia, 71800, Nilai, Negeri Sembilan, Malaysia

²Faculty of Health Science, Management and Science University (MSU), Shah Alam, Selangor, Malaysia

^*Corresponding author: m.naeim@usim.edu.my

Received: 12 October 2025; Revised: 6 January 2026; Accepted: 22 February 2026; Published: 28 April 2026

Abstract

In forensic investigations, cling film is often used by drug dealers to wrap drugs on illegal activities. Subsequently, the identification and source correspondence of cling film has become increasingly important for investigators to establish a potential link between a suspect to the crime. In this work, a non-destructive technique of ATR-FTIR spectroscopy was used with two chemometric methods of Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA) to discriminate and identify the source correspondence of 81 samples of two types of cling film (PVC and LDPE). The PCA chemometric model after non-destructive ATR-FTIR spectroscopy effectively segregated and classified the two cling film classes according to types. Furthermore, HCA was performed to investigate the structure-spectral property relationship between both types of cling film. It successfully distinguished the samples into two classes (Group 1 = LDPE samples and Group 2 = PVC samples), aligning with the PCA analysis results. This study further explored whether the trained PCA model can be extended to simulated forensic case scenario and found that all seven unknowns were correctly predicted to their original source. The findings suggest that non-destructive ATR-FTIR spectroscopy and the two chemometric methods (PCA and HCA) can be essential tools for the discrimination of cling film and source correspondence in real forensic scenario.

Keywords: analytical chemistry, chemometrics, cling film, attenuated total reflectance infrared spectroscopy, principal component analysis

References

1. Causin, V., Marega, C., Carresi, P., Schiavone, S. and Marigo, A. (2006). A quantitative differentiation method for plastic bags by infrared spectroscopy, thickness measurement and differential scanning calorimetry for tracing the source of illegal drugs. Forensic Science International, 164: 148–154.

2. Tsumura, Y., Ishimitsu, S., Kaihara, A., Yoshii, K. and Tonogai, Y. (2002). Phthalates, adipates, citrate and some of the other plasticizers detected in Japanese retail foods: A survey. Journal of Health Science, 48: 493–502.

3. Roux, C., Bull, S., Goulding, J. and Lennard, C. (2000). Tracing the source of illicit drugs through plastic packaging—a database. Journal of Forensic Sciences, 45: 99–114.

4. Burman, L. and Albertsson, A. C. (2005). Chromatographic fingerprinting – a tool for classification and for predicting the degradation state of degradable polyethylene. Polymer Degradation and Stability, 89: 50–63.

5. Sajwan, M., Aggarwal, S. and Singh, R. B. (2008). Forensic characterization of HDPE pipes by DSC. Forensic Science International, 175: 130–133.

6. Arora, T., Verma, R., Kumar, R., Chauhan, R., Kumar, B. and Sharma, V. (2021). Chemometrics based ATR-FTIR spectroscopy method for rapid and non-destructive discrimination between eyeliner and mascara traces. Microchemical Journal, 164: 106080.

7. Asri, M. N. M., Verma, R., Nor, N. A. M., Ibrahim, M. H., Sharma, V. and Ismail, D. (2021). On the discrimination between facial creams of different brands using Raman spectroscopy and partial least squares discriminant analysis for forensic application. Science & Justice, 61(6): 657–664.

8. Sharma, A., Verma, R., Kumar, R., Chauhan, R. and Sharma, V. (2020). Chemometric analysis of ATR-FTIR spectra of fingernail clippings for classification and prediction of sex in forensic context. Microchemical Journal, 159: 105504.

9. Sharma, A. and Sharma, V. (2022). Forensic analysis of cigarette ash using ATR-FTIR spectroscopy and chemometric methods. Microchemical Journal, 178: 107406.

10. Kumar, R., Sharma, K. and Sharma, V. (2020). Bloodstain age estimation through infrared spectroscopy and chemometric models. Science & Justice, 60: 538–546.

11. He, X. and Wang, J. (2019). Rapid and non-destructive forensic identification of tyre particles by attenuated total reflectance–Fourier transform infrared spectroscopy and chemometrics. Analytical Letters, 53: 714–734.

12. Socrates, G. (2015). Infrared and Raman characteristic group frequencies: tables and charts. John Wiley & Sons Ltd., UK: pp. 80 – 89.

13. Larkin, P. J. (2011). IR and Raman spectroscopy: principles and spectral interpretation. Elsevier Inc., USA: pp. 100 – 112.

14. Gilburt, J., Ingram, J. M., Scott, M. P. and Underhill, M. (1991). The analysis of cling films by infrared spectroscopy and thermal desorption capillary gas chromatography. Journal of Forensic Sciences Society, 31: 337–347.

15. Griffin, R. M. E., Lewis, R., Bennett, J., Hamill, J. and Kee, T. G. (1996). Analysis of cling films and coloured cellophanes and the application to casework. Science & Justice, 36: 219–227.

16. Laasonen, M., Rantanen, J., Harmia-Pulkkinen, T., Michiels, E., Hiltunen, R., Räsänen, M. and Vuorela, H. (2001). Near infrared reflectance spectroscopy for the fast identification of PVC-based films. Analyst, 126: 1122–1128.

17. Holman, S. W., Emmett, T. F. and Cole, M. D. (2012). A quantitative assessment of the chemical variation in food grade polyethylene cling film, a common wrapping material for illicit drugs, using attenuated total reflection-Fourier transform infrared spectroscopy. Analytical Methods, 4: 1667–1673.

18. Cleverly, B. (1979). The comparison of matching low density polyethylene bags by infrared spectroscopy. Journal of Forensic Sciences, 24: 339–345.

19. Nissen, K. E., Keegan, J. T. and Byrne, J. P. (1998). Characterization of plastic films from trace element analysis using inductively coupled plasma-mass spectrometry. Canadian Journal of Analytical Sciences and Spectroscopy, 43: 122–128.

20. Telford, C. J., Burrows, B. A., Sauzier, G., Van Bronswijk, W., Houck, M. M., Maric, M. and Lewis, S. W. (2017). Classification of polyethylene cling films by attenuated total reflectance–Fourier transform infrared spectroscopy and chemometrics. Analytical Methods, 9: 3800–3808.