Analysis of Nicotine Metabolites in Hair and Nails Using QuEChERS Method Followed by Liquid Chromatography-Tandem Mass Spectrometry

Current status of keratinized matrices in Toxicology: Comparison of hair and nails

Nails are a keratinized matrix that has been proposed as an alternative to hair to evaluate long-term and retrospective consumption of drugs of abuse and pharmaceuticals. This matrix has been gaining interest in recent years, with new studies focusing on the analysis of fingernails and/or toenails for different substances. However, nails and hair present differences in structure, growth, and incorporation pathways that may affect drug incorporation and analysis and complicate the interpretation of the results. To better understand the results in nail samples, a comparison of concentrations found in hair, fingernails, and toenails has been described in the literature for some drugs. This review unifies the results found in the literature, with special interest on studies that report paired samples from the same individuals. Differences between fingernail and toenail samples, as well as proposed cut-offs in nails, are also discussed. Definite conclusions can be reached for some drugs, but, in general, more standardized studies are needed to better understand nail results.

Determination of nicotine and cotinine in human hair using online solid phase extraction coupled with liquid chromatography-tandem mass spectrometry and their relation to hair cortisol and cortisone

Tobacco smoking is one of the critical public health threats all over the world. Since nicotine and its metabolite cotinine have been routinely used as the biomarkers to estimate the exposure to tobacco smoking, hair nicotine and cotinine analyses can provide of a retrospective index of nicotine and cotinine integrated over extended periods of several months prior to hair sampling to estimate the long-term exposure to tobacco smoking. Since the relationship between tobacco smoking and hypothalamic-pituitary-adrenal (HPA) axis is implicated in both stress response and nicotine addiction, better understanding of the association between hair nicotine, cotinine levels and hair cortisol, cortisone levels is an important prerequisite toward more adequate use of this method in future research. We here presented an online solid phase extraction (SPE) coupled with liquid chromatography- tandem mass spectrometry (LC-MS/MS) method for quantification of long-term integrated nicotine and cotinine in human hair. This method was applied to the analysis of hair nicotine and cotinine in 40 participants of smokers and nonsmokers (mean ± SD age: 46.25 ± 11.92 years; 40 % male) and the investigation of their association with hair cortisol and cortisone. Methanol together with glass tube was used for hair nicotine and cotinine extraction during the incubation time of 18-h. The limits of quantification were 1 pg/mg for nicotine as well as 0.1 pg/mg for cotinine. The inter- and intra-day coefficients of variation were below 15 %. The method recovery ranged between 90 % and 104 %. Group-level analyses revealed that smokers exhibited higher hair nicotine and cotinine levels compared to nonsmokers. Hair nicotine and cotinine levels showed significant positive associations with hair cortisol and cortisone levels in smokers (nicotine and cortisol: Spearman's ρ = 0.619, p = 0.005; cotinine and cortisol: Spearman's ρ = 0.468, p = 0.043; nicotine and cortisone: Spearman's ρ = 0.773, p = 0.000; cotinine and cortisone: Spearman's ρ = 0.531, p = 0.016), but not in nonsmokers. The presented online SPE LC-MS/MS method provides a simply and highly specific analytical strategy for the detection of nicotine and cotinine concentrations in human hair for the retrospective assessment of cumulative long-term nicotine and cotinine exposure. Furthermore, hair nicotine, cotinine levels correlate with hair cortisol, cortisone levels in smokers other than nonsmokers.

Simultaneous Determination of Six Immunosuppressants in Human Whole Blood by HPLC-MS/MS Using a Modified QuEChERS Method

A high-performance liquid chromatography-tandem mass spectrometry method was established for the simultaneous determination of mycophenolic acid, mycophenolate mofetil, tacrolimus, rapamycin, everolimus and pimecrolimus in human whole blood by optimizing the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) preparation method. Whole blood was extracted into ethyl acetate, salted out with anhydrous magnesium sulfate, and purified with ethylenediamine-N-propyl silane adsorbent. The supernatant was evaporated under nitrogen until dry and finally reconstituted in methanol. Chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column in methanol (mobile phase A)-water (optimized for 0.1% acetic acid and 10 mM ammonium acetate, mobile phase B) at a 0.3 mL·min−1 flow rate. Electrospray ionization and positive ion multiple reaction monitoring were used for detection. The time for of analysis was 13 min. The calibration curves range of tacrolimus, rapamycin, everolimus and pimecrolimus were in the range of 1−100 ng·mL−1, mycophenolate mofetil in the range of 0.1−10 ng·mL−1 and mycophenolic acid at 10−1000 ng·mL−1. All correlation coefficients were >0.993. The coefficients of variation (CV, %) for inter-day and intra-day precision were less than 10%, while the spiked recoveries were in the range of 92.1% to 116%. Our method was rapid, sensitive, specific, and reproducible for the simultaneous determination of six immunosuppressants in human whole blood. Importantly, our approach can be used to monitor drug concentrations in the blood to facilitate disease treatment.

Review of HPLC-MS methods for the analysis of nicotine and its active metabolite cotinine in various biological matrices

In recent years, tobacco smoking is a risk factor for a series of diseases including cardiovascular diseases, cerebrovascular diseases, and cancers. Nicotine, the primary component of tobacco smoke, is mainly transformed to its active metabolite cotinine, which is often used as biomarker for tobacco exposure for its higher blood concentration and longer residence time than nicotine. Various analytical methods have been developed for the determination of nicotine and cotinine in biological matrices. This article reviewed the HPLC-MS based methods for nicotine and/or cotinine analysis in various biological matrices. The sample preparation, mass and chromatographic conditions and method validation results of these methods have been summarized and analyzed. Sample was mainly pretreated by protein precipitation and/or extraction. Separation was achieved using methanol and/or acetonitrile:water (with or without ammonium acetate) on C18 columns, and acetonitrile:water (with formic acid, ammonium acetate/formate) on HILIC columns. Nicotine-d3, nicotine-d4 and cotinine-d3 were commonly used internal standards. Other non-deuterated IS were also used such as ritonavir, N-ethylnorcotinine, and milrinone. For both nicotine and cotinine, the calibration range was 0.005-35000 ng/mL, the matrix effect was 75.96% - 126.8% and the recovery was 53% - 124.5%. The two analytes were stable at room temperature for 1-10 days, at -80 °C for up to 6 months, and after 3-6 freeze-thaw cycles. Comedications did not affect nicotine and cotinine analysis.

Application of HPLC-QQQ-MS/MS and New RP-HPLC-DAD System Utilizing the Chaotropic Effect for Determination of Nicotine and Its Major Metabolites Cotinine, and trans-3'-Hydroxycotinine in Human Plasma Samples

The routine techniques currently applied for the determination of nicotine and its major metabolites, cotinine, and trans-3′-hydroxycotinine, in biological fluids, include spectrophotometric, immunoassays, and chromatographic techniques. The aim of this study was to develop, and compare two new chromatographic methods high-performance liquid chromatography coupled to triple quadrupole mass spectrometry (HPLC-QQQ-MS/MS), and RP-HPLC enriched with chaotropic additives, which would allow reliable confirmation of tobacco smoke exposure in toxicological and epidemiological studies. The concentrations of analytes were determined in human plasma as the sample matrix. The methods were compared in terms of the linearity, accuracy, repeatability, detection and quantification limits (LOD and LOQ), and recovery. The obtained validation parameters met the ICH requirements for both proposed procedures. However, the limits of detection (LOD) were much better for HPLC-QQQ-MS/MS (0.07 ng mL⁻¹ for trans-3′-hydroxcotinine; 0.02 ng mL⁻¹ for cotinine; 0.04 ng mL⁻¹ for nicotine) in comparison to the RP-HPLC-DAD enriched with chaotropic additives (1.47 ng mL⁻¹ for trans-3′-hydroxcotinine; 1.59 ng mL⁻¹ for cotinine; 1.50 ng mL⁻¹ for nicotine). The extraction efficiency (%) was concentration-dependent and ranged between 96.66% and 99.39% for RP-HPLC-DAD and 76.8% to 96.4% for HPLC-QQQ-MS/MS. The usefulness of the elaborated analytical methods was checked on the example of the analysis of a blood sample taken from a tobacco smoker. The nicotine, cotinine, and trans-3′-hydroxycotinine contents in the smoker’s plasma quantified by the RP-HPLC-DAD method differed from the values measured by the HPLC-QQQ-MS/MS. However, the relative errors of measurements were smaller than 10% (6.80%, 6.72%, 2.04% respectively).

Nicotine in Complex Samples: Recent Updates on the Pretreatment and Analysis Method

Nicotine is a significant evaluation index of tobacco and its related products' quality, but nicotine overdose can pose serious health hazards and cause addiction and dependence, thus it can be seen that it is necessary to find suitable and efficient detection methods to precisely detect nicotine in diverse samples and complex matrices. In this review, an updated summary of the latest trends in pretreatment and analytical techniques for nicotine is provided. We reviewed various sample pretreatment methods, such as solid phase extraction, solid phase microextraction, liquid phase microextraction, QuEChERS, etc., and diverse nicotine assay methods including liquid chromatography, gas chromatography, electrochemical sensors, etc., focusing on the developments since 2015. Furthermore, the recent progress in the applications and applicability of these techniques as well as our prospects for future developments are discussed.HighlightsUpdated pretreatment and analysis methods of nicotine were systematically summarized.Microextraction and automation were main development trends of nicotine pretreatment.The introduction of novel materials added luster to nicotine pretreatment.The evolutions of ion source and mass analyzer were emphasized.

Review on in vivo profiling of drug metabolites with LC-MS/MS in the past decade

Metabolite profiling is an indispensable part of drug discovery and development, enabling a comprehensive understanding of the drug's metabolic behavior. Liquid chromatography-mass spectrometry facilitates metabolite profiling by reducing sample complexity and providing high sensitivity. This review discusses the in vivo metabolite profiling involving LC-MS/MS and the utilization of QTOF, QQQ mass analyzers with a particular emphasis on a mass filter. Further, a summary of sample extraction procedures in biological matrices such as plasma, urine, feces, serum and hair as in vivo samples are outlined. toward the end, we present 15 case studies in biological matrices and their LC-MS/MS conditions to understand the metabolic disposition.

Determination of antidepressants and benzodiazepines in paired hair and nail samples

Hair and nails are keratinized matrices that can be used in Toxicology as matrices for the long-term detection of substances. Whereas hair is an established matrix with decades of use in this field, nails have been less studied, especially including a comparison to hair samples. Specifically in the case of antidepressant and benzodiazepine drugs, very few publications analyzing these drugs in nail samples exist as of yet. For this reason, in the present study a method for the detection of 12 antidepressant and benzodiazepine drugs in hair and nail samples was developed. Samples were decontaminated with 3 washes of dichloromethane, and 25 or 30 mg of hair and nails, respectively, were pulverized. Then, the samples were incubated with 1.5 mL water:ACN (50:50, v/v) with horizontal agitation for 90 min. The supernatant was evaporated and reconstituted in 200 µL of methanol and 2 mL of 2% FA in water, submitted to solid phase extraction (SPE) using Oasis MCX cartridges and analyzed by LC-MS/MS. The method was satisfactorily validated in nail and hair samples for the following parameters: linearity, LOD (0.005-0.02 ng/mg), LOQ (0.01-0.02 ng/mg), selectivity, carryover, accuracy, imprecision, matrix effect, extraction efficiency, process efficiency and autosampler stability. Matched fingernail, toenail and hair samples were obtained from 21 patients under treatment with any of the studied drugs and analyzed with the developed method. The most frequently detected drugs were venlafaxine (n = 11), trazodone (n = 6), zolpidem (n = 5), alprazolam (n = 5) and nordiazepam (n = 5). Concentrations in hair, fingernails and toenails, respectively, were 44.31 ng/mg, 8.05-43.35 ng/mg and 7.02-22.69 ng/mg for venlafaxine; 5.40-19.08 ng/mg, 0.13-1.00 ng/mg and 0.42-1.04 ng/mg for trazodone; 13.86 ng/mg, 5.19 ng/mg and 9.11 ng/mg for fluoxetine; 7.42 ng/mg, 1.85 ng/mg and 0.03-2.81 ng/mg for sertraline; 0.40-1.42 ng/mg, 0.12 ng/mg and 0.16 ng/mg for zolpidem; and 0.02-0.11 ng/mg, 0.07-1.07 ng/mg and 0.05 ng/mg for alprazolam for the patients under active treatment. Hair concentrations were higher than nail concentrations for most drugs in patients under active treatment, with the exception of diazepam (n = 1; 0.12 ng/mg in hair and 0.41 ng/mg in fingernails). Fingernail concentrations were lower than toenail concentrations in patients under active treatment in most compared cases. Comparison of fingernails and toenails of a patient with antifungal treatment did not show an observable effect in concentrations.

Sensitive Quantification of Nicotine in Bronchoalveolar Lavage Fluid by Acetone Precipitation Combined With Isotope-Dilution Liquid Chromatography-Tandem Mass Spectrometry

The United States experienced an outbreak of e-cigarette, or vaping, product use-associated lung injury (EVALI) that began in August 2019. Patient diagnosis and treatment sometimes involved bronchoscopy and collection of the bronchoalveolar lavage (BAL) fluid. Although this matrix has been useful for understanding some chemical exposures in the lungs, no methods existed for measuring the nicotine content. Therefore, we developed a simple and sensitive method for measuring nicotine in the BAL fluid. Nicotine was extracted from the BAL fluid using acetone precipitation in a 96-well plate format to increase the sample throughput (200 samples/day). We optimized liquid chromatography column conditions (e.g., mobile phase, column temperature) and mass spectrometry parameters to improve the signal-to-noise ratio and lower limits of detection (LOD) for measuring nicotine in the BAL fluid. The LOD for nicotine in the BAL fluid was 0.050 ng/mL at a sample volume of 40 μL of the BAL fluid. The within-day and between-day imprecision and bias were less than 10%. This method detected nicotine in 15 of 43 BAL fluids from EVALI case patients. This method is useful for understanding recent inhalational exposure to nicotine as part of characterizing EVALI or similar illnesses.