Although chlorine (Cl2) has been used as a chemical warfare agent since World War I there is no known specific and reliable biomarker to indicate the presence of chlorine. We distinguished chlorinated human nails from unchlorinated ones using Raman spectroscopy and Fourier Transform Infrared (FT-IR) Spectroscopy. This research was carried out between October 2018 and July 2019 on two nail samples taken from 55 male and 104 female volunteers. One sample from each participant was chlorinated, while the second sample was used as a control. Spectral data were collected from chlorinated and unchlorinated (control) human nails using Raman and FT-IR spectroscopy. Raman measurements were made between 100 and 3200 cm−1, while FT-IR measurements were recorded over the range of 650 to 4000 cm−1. Partial least squares regression-discriminant analysis (PLS-DA) was used to develop classification models for each spectral instrument. Results showed that the control and chlorinated nail samples were successfully discriminated with similar results achieved with both instruments. Minor differences were observed in the performance of classification models. The FT-IR spectroscopy model (sensitivity = 95%, specificity = 99%, accuracy = 97%) was found to be more successful with a smaller margin of error (sensitivity = 95%, specificity = 99%, accuracy = 96%) compared to the Raman spectroscopy model. This method can be used successfully for both ante-mortem and post-mortem diagnosis of chlorine exposure.
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Wehling F. Deterring terrorism: Theory and practice. In: Wenger A, Wilner A, editors. A toxic cloud of mystery: Lessons from Iraq for deterring CBRN terrorism. Stanford: Stanford University Press; 2012. p. 273–98. 362.
Barber R. Uniting for peace not aggression: responding to chemical weapons in Syria without breaking the law. J Conflict Security Law. 2019;24(1):71–110.
Hemstrom P, et al. L-alpha-phosphatidylglycerol chlorohydrins as potential biomarkers for chlorine gas exposure. Analyt Chem. 2016;88(20):9972–9.
OPCW (2020). Note by the Technical Secretariat third report of the Opcw fact-finding mission in Syria. https://photos.state.gov/libraries/netherlands/328666/pdfs/THIRDREPORTOFTHEOPCWFACTFINDINGMISSIONINSYRIA.pdf.
Irving RC, Dickson SJ. The detection of sedatives in hair and nail samples using tandem LC-MS-MS. Forensic Sci Int. 2007;166(1):58–67.
Gambelunghe C, et al. Hair analysis by GC/MS/MS to verify abuse of drugs. J App Toxicol. 2005;25:205–11.
Cognard E, et al. Analysis of cocaine and three of its metabolites in hair by gas chromatography-mass spectrometry using ion-trap detection for CI/MS/MS. J Chromatog B-Analyt Technol Biomed Life Sci. 2005;826:17–25.
Lachenmeier K, Musshoff F, Madea B. Determination of opiates and cocaine in hair using automated enzyme immunoassay screening methodologies followed by gas chromatographic-mass spectrometric (GC-MS) confirmation. Forensic Sci Int. 2006;159:189–99.
Engelhart DA, Jenkins AJ. Detection of cocaine analytes and opiates in nails from postmortem cases. J Analyt Toxicol. 2002;26:489–92.
Lemos NP, et al. Analysis of morphine by RIA and HPLC in fingernail clippings obtained from heroin users. J Forensic Sci. 2000;45:407–12.
Valente-Campos S, et al. Validation of a method to detect cocaine and its metabolites in nails by gas chromatography-mass spectrometry. Forensic Sci Int. 2006;159:218–22.
Smith WE, et al. Handbook of Raman spectroscopy: From the research laboratory to the process line. Practical Spectroscopy. New York: Marcel Dekker; 2001. p. 733.
Movasaghi Z, Rehman S. Ur Rehman DI. Fourier transform infrared (FTIR) spectroscopy of biological tissues. App Spectroscopy Rev. 2008;43:134–79.
Naurecka M, et al. FTIR-ATR and FT-Raman spectroscopy for biochemical changes in oral tissue. Am J Analyt Chem. 2017;8:180–8.
Untereiner V, et al. Bile analysis using high-throughput FTIR spectroscopy for the diagnosis of malignant biliary strictures: a pilot study in 57 patients. J Biophotonics. 2014;7:241–53.
Carter JC, Brewer WE, Angel SM. Raman spectroscopy for the in situ identification of cocaine and selected adulterants. Appl Spectroscopy. 2000;54:1876–81.
Tsuchihashi H, et al. Determination of methamphetamine and its related compounds using fourier transform raman spectroscopy. App Spectroscopy. 1997;51:1796–9.
Ryder A. Classification of narcotics in solid mixtures using principal component analysis and Raman spectroscopy. J Forensic Sci. 2002;47:275–84.
Calcerrada M, García-Ruiz C. Analysis of questioned documents: a review. Anal Chim Acta. 2015;853:143–66.
Cummins N, et al. Raman spectroscopy of fingernails: a novel tool for evaluation of bone quality? Spectroscopy. 2010;24:517–24.
Beattie JR, et al. Raman spectroscopic analysis of fingernail clippings can help differentiate between postmenopausal women who have and have not suffered a fracture. Clinical medicine insights. Arthritis Musculoskeletal Dis. 2016;9:109–16.
Rohart F, et al. mixOmics: An R package for 'omics feature selection and multiple data integration. PLoS Comp Biol. 2017;13:e1005752.
Team RC. A language and environment for statistical computing. Computing. 2018;1.
Gerding H, Haring HG. Raman spectra of aliphatic chlorine compounds: V. Chloroethers and chloroalcohols. Recueil des Travaux Chimiques des Pays-Bas. 1955;74:841–75.
Sommerville D, et al. Review and assessment of chlorine mammalian lethality data and the development of a human estimate R-1. Military Op Res. 2010;15:59–86.
Evans RB. Chlorine: state of the art. Lung. 2005;183:151–67.
Gaskin S, et al. In-vitro methods for testing dermal absorption and penetration of toxic gases. Toxicol Mech Methods. 2014;24:70–2.
Aggarwal RL, et al. Raman spectra and cross sections of ammonia, chlorine, hydrogen sulfide, phosgene, and sulfur dioxide toxic gases in the fingerprint region 400-1400 cm−1. AIP Adv. 2016;6:025310.
Brzózka P, Kolodziejski W. Sex-related chemical differences in keratin from fingernail plates: a solid-state carbon-13 NMR study. RSC Adv. 2017;7:28213–23.
Widjaja E, Lim GH, An A. A novel method for human gender classification using Raman spectroscopy of fingernail clippings. Analyst. 2008;133:493–8.
Ramesh S, et al. FTIR studies of PVC/PMMA blend based polymer electrolytes. Spectrochimica Acta. Part A - Mol Biomol Spectroscopy. 2007;66:1237–42.
Dickerson MB, et al. Keratin-based antimicrobial textiles, films, and nanofibers. J Materials Chem B. 2013;1:5505–14.
This work was partly supported by OPCW [Grant No. L/ICA/ICB/210503/17],
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Ethics approval (include appropriate approvals or waivers)
This study was approved by the Bulent Ecevit University Medical Ethics Committee (2018-62-28/02).
Consent to participate and publication (include appropriate statements)
55 male and 104 female volunteers were informed and gave their consent to the study.
Code availability (software application or custom code)
-The mixOmics package 22, 23 was used to develop classification models in R software (R Core Team, 2018).
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Toprak, S., Kahriman, F., Dogan, Z. et al. The potential of Raman and FT-IR spectroscopic methods for the detection of chlorine in human nail samples. Forensic Sci Med Pathol 16, 633–640 (2020). https://doi.org/10.1007/s12024-020-00313-5