A new metabolomics-based strategy for identification of endogenous markers of urine adulteration attempts exemplified for potassium nitrite

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Hair analysis has become a valuable tool in forensic toxicology to assess drug or alcohol abstinence. Yet, hair adulteration by cosmetic products presents a major challenge for forensic hair analysis. Oxidative treatments, e.g. bleaching, may lead to analyte loss and thereby to false negative results. Currently, the eumelanin degradation product 1H-pyrrole-2,3,5-tricarboxylic acid (PTCA) serves as a marker for oxidative hair treatment, but requires the definition of cut-off values. To investigate further eumelanin degradation products as markers for oxidative hair treatment, hair samples with and without in vitro bleaching (hydrogen peroxide (H 2 O 2 ) concentrations 1.9% up to 12%; incubation times 15 min, 30 min, 60 min) were analyzed by liquid chromatography coupled to high-resolution time of flight mass spectrometry (HPLC-HRMS). The distribution of eumelanin degradation products along the hair shaft was investigated for routine applicability after segmentation of cosmetically untreated hair samples and authentically treated hair samples. The signals of the eumelanin degradation products PTCA, 1H-pyrrole-2,-3,4-tricarboxylic acid (isoPTCA), and 1H-pyrrole-2,3,4,5-tetracarboxylic acid (PTeCA) were found to be significantly elevated after in vitro bleaching already with low H 2 O 2 concentrations and after short incubation times. In contrast to PTCA and isoPTCA, PTeCA was not detectable in cosmetically untreated segments up to 12 cm from hair root and was only formed through the oxidation process. The results of the study show that the detection of PTeCA within the proximal 3 to 6 cm segment can be applied to reliably detect hair adulteration attempts through hair bleaching. K E Y W O R D Shair biomarker, melanin degradation, oxidative hair treatment, PTCA, PTeCA

Section: Hplc-hrms Analysismentioning

confidence: 99%

A possible new oxidation marker for hair adulteration: Detection of PTeCA (1H‐pyrrole‐2,3,4,5‐tetracarboxylic acid) in bleached hair

Eisenbeiss

Binz

Baumgartner

et al. 2019

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“…21 Recently, first data have been published on changes in the human metabolome caused by 3,4-methylenedioxymethamphetamine (MDMA). 24 In postmortem investigations, metabolomics could also be used for the estimation of the postmortem interval (PMI) with, for example, amino acids and creatinine being elevated postmortem 25,26 or with sterol sulfates and very-long-chain fatty acids declining during the postmortem period. 17,18 Further, there are increasing analytical problems in the detection of new psychoactive substances (NPS), which are flooding the drug market worldwide.…”

Section: Introductionmentioning

confidence: 99%

Analytical considerations for (un)‐targeted metabolomic studies with special focus on forensic applications

Boxler

Schneider

Kræmer

et al. 2018

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Over the past few years, the interest in metabolomics has increased in various fields including forensic toxicology. Forensic analysis typically requires a high degree of accuracy, which is often a problem in metabolomics applications. We aimed for a systematic evaluation of different analytical considerations of a metabolomics workflow allowing a targeted approach within an untargeted setup. Samples with 69 metabolites from different chemical classes were qualitatively and quantitatively analyzed on a high resolution quadrupole time of flight mass spectrometer coupled to liquid chromatography (UHPLC-QTOF). Three issues were addressed: (a) Two different approaches on "blind matrix" a simulated body fluid (SBF) and plasma-filtrate, were tested for calibration samples; (b) comparison of two different HPLC columns, reverse-phase (RP) and hydrophilic interaction chromatography (HILIC); and (c) comparison of three different acquisition modes (TOF-MS, information dependent data acquisition (IDA), and sequential window acquisition of all theoretical fragment-ion spectra (SWATH). Samples were measured repeatedly for method comparison based on sensitivity, accuracy, precision, and detection robustness. The blind matricesshowed similar accuracy for most analytes, while SBF provided an easier preparation with satisfying results. To cover a wide part of the human metabolome, a combination of RP and HILIC showed the best results. The different scan modes performed equally regarding metabolite quantification while TOF-MS was more sensitive but lacked MS/MS spectra generation. IDA and SWATH files were aligned to various databases where IDA showed good MS/MS spectra matches. SWATH seemed to be beneficial in detection rate but was incompatible with many important software tools in metabolomics.

“…12 An overview of peak area ratios between paired treated and untreated samples for all adulterants in a higher concentration range is given in Figure 1. 12 An overview of peak area ratios between paired treated and untreated samples for all adulterants in a higher concentration range is given in Figure 1.…”

Section: Effects Of Different Adulterants On Endogenous Urinary Marmentioning

confidence: 99%

“…Few systematic studies on the prevalence of such attempts were performed and suggest detection only in low, but still relevant numbers. 12 Therein, overall 15 markers were identified and further tested for their routine applicability. 11 An ideal workflow, particularly for high-throughput testing, would involve simultaneous detection of adulteration attempts in the same run with drug detection.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of endogenous urinary biomarkers for indirect detection of urine adulteration attempts by five different chemical adulterants in mass spectrometry methods

Steuer

Kamber

Kræmer

2018

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Reliable detection of urine adulteration attempts to circumvent positive drug testing represents a critical step for laboratories in abstinence control settings. An ideal workflow for high-throughput testing would involve simultaneous detection of adulteration attempts in the same run with drug detection. Monitoring of degraded or oxidized endogenous urinary compounds as indirect markers has been previously evaluated for that purpose exemplified for the adulterant potassium nitrite (KNO 2 ).Fifteen, previously identified endogenous markers should now be evaluated for their general applicability to detect adulteration attempts for the adulterants hypochloritebased bleach (NaOCl), peroxidase and peroxide (H 2 O 2 ), pyridinium chlorochromate (PCC), and iodine (I 2 ). Initial experiments revealed similar results for the tested adulterants regarding degradation of indolylacryloylglycine (IAG), uric acid (UA), or UA derivatives. 5-Hydroxyisourate (HIU), the oxidation product of UA, was however only formed by KNO 2 , PCC, and H 2 O 2 . Amino acids showed larger adulterantdependent differences. All reactions were shown to be influenced by the adulterant concentration and the urinary pH with large variances depending on compound and adulterant. Except for HIU/PCC, all markers were stable within +/− 30% variation for all adulterants at −20°C. Receiver operating characteristics indicated best sensitivity and specificity over all adulterants for IAG (specificity 0.9, sensitivity 1.0) and UA (specificity 1.0, sensitivity 0.9). HIU gave best results for KNO 2 , PCC, and H 2 O 2 and N-acetylneuraminic acid for PCC and H 2 O 2 , respectively. When integrating a limited number of targets into existing screening methods, monitoring of UA, IAG, N-acetylneuraminic acid, and HIU is recommended.