RESUMO
Two chemists employed a three-device rapid screening "toolkit" consisting of a handheld Raman spectrometer, transportable mass spectrometer, and portable Fourier transform infrared (FT-IR) spectrometer at an international mail facility (IMF) satellite laboratory to examine unknown (unlabeled/mislabeled) products for the presence of active pharmaceutical ingredients (APIs). Phase I of this project previously demonstrated that this toolkit was the most effective collection of instruments for identifying APIs in product types collected at IMFs during a nationwide mail blitz and Phase II of this project previously demonstrated that results generated using the toolkit during a satellite laboratory pilot program were as reliable as those generated by a full-service library when two or more of these instruments identify an API. This study (Phase III) described the results of the satellite laboratory toolkit during production mode and encompassed the period ranging from June 2021 through December 2022. During this study, a total of 858 products were examined on-site at the IMF. The satellite laboratory yielded conclusive results for 726 (84.6%) products, which were used to support regulatory action, and identified 132 (15.4%) products that required additional full-service laboratory analyses due to inconclusive results. The satellite and full-service laboratory verified/confirmed at least one API/related substance in 617 (71.9%) products. A total of 709 APIs/related substances were found in the 617 products, and 202 of these 709 compounds were unique/different. Overall, during Phases I through III of this program, 350 different substances have been identified in products collected at IMFs.
Assuntos
Espectrometria de Massas , Humanos , Preparações Farmacêuticas/análise , Espectrometria de Massas/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Rotulagem de Medicamentos , Serviços Postais , Laboratórios , Princípios AtivosRESUMO
The inclusion of nurse practitioners (NPs) in critical care transport teams has the potential to enhance patient care and improve team operations. NPs can manage complex clinical situations during transport and excel in various roles such as leadership, education, mentoring, research, quality improvement, and clinical expertise. As we navigate the evolving landscape of critical care transport, it is crucial to explore the potential benefits offered by NPs. Their distinct skills and experiences effectively position them to improve patient outcomes, enhance team performance, and contribute to health care's financial sustainability. This article discusses the role of NPs in critical care transport, providing insight into their current uses, and recommendations for optimal use.
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Profissionais de Enfermagem , Humanos , Cuidados Críticos , Liderança , Competência ClínicaRESUMO
The opium poppy (Papaver somniferum) is a global commercial crop that has been historically valued for both medicinal and culinary purposes. Naturally occurring opium alkaloids including morphine, codeine, thebaine, noscapine, and papaverine are found primarily in the latex produced by the plant. If the plant is allowed to fully mature, poppy seeds that do not contain the opium alkaloids will form within the pods and may be used in the food industry. It is possible for the seeds to become contaminated with alkaloids by the latex during harvesting, posing a potential health risk for consumers. In the USA, there have been more than 600 reported adverse events including 19 fatalities that may be linked to the consumption of a contaminated poppy-containing product such as home-brewed poppy seed tea. Unwashed poppy seeds and pods may be purchased over the Internet and shipped worldwide. The Forensic Chemistry Center, US Food and Drug Administration (FDA) has evaluated several mass spectrometers (MS) capable of rapid screening to be used for high-throughput analysis of samples such as poppy seeds. These include a direct analysis in real-time (DART) ambient ionization source coupled to a single-quadrupole MS, an atmospheric solids analysis probe (ASAP) ionization source coupled to the same MS, and ion mobility spectrometers (IMS). These instruments have been used to analyze 17 poppy seed samples for the presence of alkaloids, and the results were compared to data obtained using liquid chromatography with mass spectral detection (LC-MS/MS). Results from the 17 poppy seed samples indicate that the DART-MS, ASAP-MS, and IMS devices detect many of the same alkaloids confirmed during the LC-MS/MS analyses, although both the false-positive and false-negative rates are higher, possibly due to the non-homogeneity of the samples and the lack of chromatographic separation.
Assuntos
Alcaloides , Papaver , Papaver/química , Ópio/análise , Cromatografia Líquida , Espectrometria de Mobilidade Iônica , Látex/análise , Espectrometria de Massas em Tandem , Morfina , Alcaloides/análise , Sementes/químicaRESUMO
Developing methods to rapidly screen for novel synthetic 2-benzylbenzimidazole opioids, also known as nitazenes, has become increasingly important due to their high potency. These compounds have potency comparable or exceeding that of fentanyl by up to 10 times and have been implicated in approximately 5% of all drug overdose deaths in the United States in 2021. This paper details the authenticity determination of suspect tablets and the identification of three nitazene analogs (N-pyrrolidino etonitazene, isotonitazene, and etodesnitazene) in suspect tablets seized at a mail facility using Raman and surface-enhanced Raman scattering (SERS) with handheld devices, portable Fourier transform infrared spectrometer (FT-IR), and a direct analysis in real-time ambient ionization coupled to a thermal desorption unit and a mass spectrometer (DART-TD-MS). These methods are rapid and excellent for screening opioids in suspect tablets but could not fully determine the exact structure of some of the nitazene analogs present due to spectral similarities or similar fragmentation patterns. Liquid chromatography-mass spectrometry (LC-MS) confirmed the presence of these nitazene compounds in addition to other opioids/drugs that were in trace quantities. The quantitative high-performance liquid chromatography coupled with ultraviolet (HPLC-UV) detection experiments determined that the suspect tablets contained an average of 0.817 mg of N-pyrrolidino etonitazene per tablet. The results obtained reveal that the simultaneous deployment of these complementary and orthogonal portable analytical techniques as part of a workflow allows suspect tablets to be screened and nitazene-type drugs to be identified in suspect counterfeit tablets at remote sampling sites.
Assuntos
Análise Espectral Raman , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectrometria de Massas/métodos , Cromatografia Líquida , ComprimidosRESUMO
A satellite laboratory "toolkit" consisting of a handheld Raman spectrometer, portable direct analysis in real-time mass spectrometer (DART-MS) and portable Fourier transform infrared (FT-IR) spectrometer was employed to examine 926 pharmaceutical, unknown and dietary supplement products collected at an international mail facility (IMF) for the presence of declared and undeclared active pharmaceutical ingredients (APIs) over the course of 68 working days. The toolkit successfully identified over 650 APIs, including over 200 unique APIs, using two or more devices. The performance of each individual device, and toolkit as a whole, were evaluated on all products and a subset of the products was forwarded to full-service laboratories for confirmatory analysis to determine false positive and false negative rates of the toolkit. The subset consisted of seven negative items (those not found to contain APIs using the toolkit) and 124 positive items (those found to contain at least one API using the toolkit). Overall, no false positives were detected in the negative items and only four false negatives and five false positives were detected in the positive items. Regarding the positive items, 119 of the 124 items were found to contain at least one API using at least two toolkit devices; each of these APIs were confirmed by a full-service laboratory. Furthermore, 90.2% of the APIs found by confirmatory laboratory analysis were detected by at least two toolkit devices. Based on these metrics and the fact that no false positives were detected by more than one device, it was concluded that when the toolkit detects and subsequently verifies/confirms an API using two or more devices, the results are as reliable as those generated by a full-service laboratory.
Assuntos
Laboratórios , Serviços Postais , Análise de Fourier , Espectroscopia de Infravermelho com Transformada de Fourier , Preparações FarmacêuticasRESUMO
In the screening of an injectable liquid marketed for body building, a steroid resembling 1-testosterone was found. The compound of interest was isolated using HPLC-UV detection coupled to an analytical scale fraction collector and subsequently characterized using HRAM-MS, NMR spectrometry, and GC-MS. The designer steroid was identified as 17ß-hydroxy 5α-androst-1-en-3-one cypionate, an analog of 1-testosterone that had not been reported.
Assuntos
Esteroides , Testosterona , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas/métodosRESUMO
Incidence of e-cigarette, or vaping, product use-associated lung injury (EVALI) has been linked to the vaping of tetrahydrocannabinol (THC) products to which vitamin E acetate (VEA) has been added. In this work we vaped THC/VEA mixtures at elevated power levels using a variety of ceramic coil vaping cartridges and a commercially available vaping device, while simultaneously measuring temperature and collecting the vaporized condensate. The collected vapor condensate was analyzed for evidence of VEA decomposition by GC/MS, GC/FT-IR/MS, and LC-APCI-HRMS/MS. Mean temperature maxima for all examined cartridges at the selected power exceeded 430°C, with a range of 375-569°C, well beyond that required for thermal decomposition of VEA. The percent recovery of VEA and Δ9-THC from the vaporized mixture in six cartridges ranged from 71.5 to 101% and from 56.4 to 88.0%, respectively. Analysis of the condensed vaporized material identified VEA decomposition products duroquinone (DQ), 1-pristene, and durohydroquinone monoacetate (DHQMA); a compound consistent with 4-acetoxy-2,3,5-trimethyl-6-methylene-2,4-cyclohexadienone (ATMMC) was also detected. The concentration of DQ produced from vaporization of the THC/VEA mixture in one cartridge was found to be 4.16 ± 0.07 µg per mg of vapor condensate.
RESUMO
A "toolkit" consisting of a handheld Raman spectrometer equipped with a 1064 nm laser, a portable Fourier transform infrared (FT-IR) spectrometer and a portable direct analysis in real-time mass spectrometer (DART-MS) was employed in a laboratory setting to examine 82 representative products collected during a nationwide mail blitz for the presence of APIs. These results were compared to those obtained using laboratory-based methods; 8 of the products were not found to contain APIs and 74 of the products were found to contain a total of 88 APIs (65 of the 88 APIs were unique). The individual performance of each device and combined performance of the three-device toolkit were evaluated with regard to true positives, true negatives, false positives and false negatives. Using this toolkit, 81 (92.0 %) of the APIs were detected by at least one technique and 47 (64.8 %) of the APIs were detected by at least two techniques. Seven false negatives (8.0 %) were encountered and while the toolkit yielded 12 false positives, no false positives were detected by more than one technique. Overall, this study demonstrated that when the toolkit detects an API using two or more devices, the results are as reliable as those generated by a full-service laboratory.
Assuntos
Preparações Farmacêuticas , Serviços Postais , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The development of a method for the rapid screening of food and drug products for constituents such as mitragynine, the most abundant alkaloid found in Mitragyna speciosa (kratom) plant leaves, has become increasingly important. The use of kratom is said to produce stimulant or narcotic effects and poses risks of addiction, abuse, and dependence, much like other opioids. Direct Analysis in Real Time with thermal desorption mass spectrometry (DART-TD-MS), hand-held mass spectrometry, portable ion mobility spectrometry (IMS), and portable Fourier-transform infrared spectroscopy (FT-IR) were each evaluated as field-deployable screening techniques for the detection of mitragynine in food and drug products. These devices offer the potential for rapid, early detection of mitragynine in suspect products entering the United States through international mail facilities and other ports of entry. Ninety-six kratom products, including capsules, bulk powder, and bulk plant material, were analyzed by either direct sampling of the solid material or by solvent extraction. True and false positive and negative results are reported, based on comparison to results from qualitative screening using gas chromatography with mass spectral detection (GC-MS), liquid chromatography with mass spectral detection (LC-MS), and/or quantitative screening using high-performance liquid chromatography with ultraviolet detection (HPLC-UV), with a discussion of the assessment of each technique for use in the field. Each device demonstrated attributes that would be favorable for use in screening of suspected mitragynine-containing products at places like ports of entry, and simultaneous deployment of two or more of these devices as part of a workflow would be the most effective for rapid screening of these products. This combination of rapid screening orthogonal techniques suited to a non-laboratory environment will allow onsite destruction of products found to contain mitragynine.
Assuntos
Mitragyna , Alcaloides de Triptamina e Secologanina , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
A simple, quick, selective, sensitive, and effective field-friendly method capable of being used by nonexperts has been developed for detecting mitragynine in Mitragyna speciosa (kratom) using surface-enhanced Raman spectroscopy (SERS). Over 100 samples and blanks (known to be either positive or negative for the presence of mitragynine) were examined in duplicate using five identical handheld Raman spectrometers, which provided a data set of over 1,000 examinations. Based on the results of these analyses, the method yielded a true-positive rate of 99.3%, a true-negative rate of 97.9%, a false-positive rate of 2.1%, and a false-negative rate of 0.7%. The average minimum detectable concentration (Cm ) of mitragynine that reproducibly yielded a match for one of the library spectra on all five instruments was determined to be 342 ng/mL (ppb). This Cm value is a conservative estimate considering that the extraction process was not fully optimized by this study, which was not necessary since the Cm value achieved was well below typical mitragynine concentrations in kratom (1.3-2.3%). The method is ideal (i) for prioritizing samples for additional testing using other more time-consuming laboratory-based techniques needed to detect and quantify mitragynine and (ii) for field use at international mail facility (IMF) satellite laboratories to help interdict kratom and prevent this dangerous product from reaching the U.S. supply chain.
Assuntos
Mitragyna/química , Alcaloides de Triptamina e Secologanina/isolamento & purificação , Análise Espectral Raman , Cromatografia Líquida , Toxicologia Forense/métodos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Valor Preditivo dos Testes , Análise Espectral Raman/instrumentaçãoRESUMO
Carcinoma showing thymus-like elements (CASTLE) is a rare tumor, most commonly found in the thyroid gland. Here we report a case of CASTLE tumor localized to the parotid gland, recognized in retrospect after a late manifestation of symptomatic pleural carcinomatosis. The original tumor in the parotid gland was treated by surgery followed by radiotherapy. Ten years later, a metastatic disease with recurrent pleural effusions occurred. Pleural carcinomatosis was strongly positive for CD5, CD117, and p63 as was the original tumor of the parotid, which allowed the diagnosis of a CASTLE tumor. Additionally, the pleural tumor expressed high levels of programmed death ligand 1 (PD-L1), and the patient underwent treatment with the monoclonal PD-L1 inhibitor pembrolizumab achieving a partial remission. To the best of our knowledge, this is the first patient with a metastatic CASTLE tumor treated with a PD-L1 inhibitor.
RESUMO
A liquid chromatography-mass spectrometry (LC-MS) screen for known anabolic-androgenic steroids in a dietary supplement product marketed for "performance enhancement" detected an unknown compound having steroid-like spectral characteristics. The compound was isolated using high performance liquid chromatography with ultraviolet detection (HPLC-UV) coupled with an analytical scale fraction collector. After the compound was isolated, it was then characterized using gas chromatography with simultaneous Fourier Transform infrared detection and mass spectrometry (GC-FT-IR-MS), liquid chromatography-high resolution accurate mass-mass spectrometry (LC-HRAM-MS) and nuclear magnetic resonance (NMR). The steroid had an accurate mass of m/z 285.1847 (error-0.57 ppm) for the protonated species [M + H]+ , corresponding to a molecular formula of C19 H24 O2 . Based on the GC-FT-IR-MS data, NMR data, and accurate mass, the compound was identified as androsta-3,5-diene-7,17-dione. Although this is not the first reported identification of this designer steroid in a dietary supplement, the data provided adds information for identification of this compound not previously reported. This compound was subsequently detected in another dietary supplement product, which contained three additional active ingredients.
Assuntos
Androstadienos/análise , Drogas Desenhadas/análise , Suplementos Nutricionais/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Espectroscopia de Infravermelho com Transformada de Fourier , Detecção do Abuso de SubstânciasRESUMO
New designer steroids are continually being encountered in dietary supplements that claim to increase muscle mass, but quantitative analysis of such ingredients is challenging due to the availability, quality, or cost of commercial reference materials. Although standard reference material typically becomes available for these emerging compounds, laboratories often face the challenge of finding properly certified materials from accredited suppliers, due to traceability requirements. Several of these designer steroids have been isolated and identified using multiple structural elucidation tools. Structural characteristics of these compounds of interest were evaluated and molar absorptivity data was collected and compared to several readily available steroid standards using ultraviolet/visible spectroscopy. This approach was used to find suitable compounds for use as surrogate reference materials in the semi-quantitative determination of two designer steroids, 1-dehydroepiandrosterone (1-androsterone) and 6ß-chloro-4-androsten-17ß-ol-3-one (6ß-chlorotestosterone). Laboratory-fortified matrix samples and dietary supplement samples were analyzed using this method for the estimation of 1-androsterone and 6ß-chlorotestosterone by HPLC-UV. Assay values obtained for the estimation of 1-androsterone in a dietary supplement sample using a prasterone or dehydroepiandrosterone (DHEA) standard curve were 100% of those obtained using a 1-androsterone reference standard, once it became commercially available. Estimations for 6ß-chlorotestosterone in laboratory-fortified matrix samples using a testosterone standard curve were 92%-93% of those obtained using isolated 6ß-chlorotestosterone as "reference material."
Assuntos
Desidroepiandrosterona/análise , Desidroepiandrosterona/química , Testosterona/análogos & derivados , Cápsulas/química , Cromatografia Líquida de Alta Pressão , Desidroepiandrosterona/isolamento & purificação , Suplementos Nutricionais/análise , Padrões de Referência , Espectrofotometria , Testosterona/análise , Testosterona/química , Testosterona/isolamento & purificaçãoRESUMO
Capsules that were labeled to be performance-enhancing dietary supplements obtained during an investigation were found to contain an unrecognized steroid-like substance. This compound was isolated by liquid chromatography (LC) fraction collection and characterized using several qualitative analytical techniques, including ultraviolet (UV) spectroscopy, gas chromatography-mass spectrometry (GC-MS), liquid chromatography-high resolution accurate mass-mass spectrometry (LC-HRAM-MS), as well as 1 H, 13 C, and two-dimensional nuclear magnetic resonance (NMR) spectrometry. This multi-technique analytical approach was used to identify the designer steroid as 6ß-chloro-4-androsten-17ß-ol-3-one (6ß-chlorotestosterone), an analog of testosterone about which little has been published.
Assuntos
Suplementos Nutricionais/análise , Testosterona/análogos & derivados , Cápsulas/química , Técnicas de Química Analítica/métodos , Cromatografia Líquida , Espectrometria de Massas em Tandem , Testosterona/análiseRESUMO
This manuscript is a continuation of a recent study that described the use of fully integrated gas chromatography with direct deposition Fourier transform infrared detection and mass spectrometric detection (GC-FT-IR-MS) to identify and confirm the presence of sibutramine and AB-FUBINACA. The purpose of the current study was to employ the GC-FT-IR portion of the same instrument to quantify these compounds, thereby demonstrating the ability to identify, confirm, and quantify drug substances using a single GC-FT-IR-MS unit. The performance of the instrument was evaluated by comparing quantitative analytical figures of merit to those measured using an established, widely employed method for quantifying drug substances, high performance liquid chromatography with ultraviolet detection (HPLC-UV). The results demonstrated that GC-FT-IR was outperformed by HPLC-UV with regard to sensitivity, precision, and linear dynamic range (LDR). However, sibutramine and AB-FUBINACA concentrations measured using GC-FT-IR were not significantly different at the 95% confidence interval compared to those measured using HPLC-UV, which demonstrates promise for using GC-FT-IR as a semi-quantitative tool at the very least. The most significant advantage of GC-FT-IR compared to HPLC-UV is selectivity; a higher level of confidence regarding the identity of the analyte being quantified is achieved using GC-FT-IR. Additional advantages of using a single GC-FT-IR-MS instrument for identification, confirmation, and quantification are efficiency, increased sample throughput, decreased consumption of laboratory resources (solvents, chemicals, consumables, etc.), and thus cost.
Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Ciclobutanos/análise , Ciclobutanos/química , Ciências Forenses/métodos , Indazóis/análise , Indazóis/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos TestesRESUMO
A simple, fast, sensitive and effective pass/fail field-friendly method has been developed for detecting sildenafil in suspect Viagra and unapproved tablets using handheld Raman spectrometers and silver colloids. The method involves dissolving a portion of a tablet in water followed by filtration and addition of silver colloids, resulting in a solution that can be measured directly through a glass vial. Over one hundred counterfeit Viagra and unapproved tablets were examined on three different devices during the method development phase of the study. While the pass/fail approach was found to be 92.6% effective on average, the efficacy increased to 97.4% on average when coupled with the software's "Discover Mode" feature that allows the user to compare a suspect spectrum to that of a stored sildenafil spectrum. The lowest concentration of sildenafil in a water/colloid solution that yielded a "Pass" was found to be 7.6µg/mL or 7.6 parts per million (ppm). For the analysis of suspect tablets, this value was found to be as low as 10µg/mL and as high as 625µg/mL. This variability was likely related to the tablet formulation, e.g., concentration of sildenafil, presence and concentration of water-soluble and/or water-insoluble ingredients. However, since most counterfeit Viagra and unapproved tablets contain >50mg sildenafil per tablet, such low concentrations will not be encountered often. Limited in-lab and in-field validation studies were conducted in which analysts/field agents followed the procedure outlined in this study for small sample sets. These individuals were provided with written instructions, a â¼20min demonstration regarding how to perform the procedure and use the instrument, and a kit with field-friendly supplies (purified bottled water from a local grocery store, disposable plastic pipettes, eye-dropper with a silver colloid solution, etc.). The method proved to be 98.3% and 91.7% effective for the in-lab and in-field validation studies, respectively, which demonstrated the ruggedness, simplicity and practicality of the method.
Assuntos
Citrato de Sildenafila/química , Prata/química , Comprimidos/análise , Comprimidos/química , Química Farmacêutica/métodos , Solubilidade , Análise Espectral Raman/métodosRESUMO
Distortion-product otoacoustic emissions (DPOAEs) arise in the cochlea in response to two tones with frequencies f1 and f2 and mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Wave interference between these components limits the accuracy of DPOAEs when evaluating the function of the cochlea with conventional continuous stimulus tones. Here, DPOAE components are separated in the time domain from DPOAE signals elicited with short stimulus pulses. The extracted nonlinear-distortion components are used to derive estimated distortion-product thresholds (EDPTs) from semi-logarithmic input-output (I/O) functions for 20 normal-hearing and 21 hearing-impaired subjects. I/O functions were measured with frequency-specific stimulus levels at eight frequencies f2 = 1, , 8 kHz (f2/f1 = 1.2). For comparison, DPOAEs were also elicited with continuous primary tones. Both acquisition paradigms yielded EDPTs, which significantly correlated with behavioral thresholds (p < 0.001) and enabled derivation of estimated hearing thresholds (EHTs) from EDPTs using a linear regression relationship. DPOAE-component separation in the time domain significantly reduced the standard deviation of EHTs compared to that derived from continuous DPOAEs (p < 0.01). In conclusion, using frequency-specific stimulus levels and DPOAE-component separation increases the reliability of DPOAE I/O functions for assessing cochlear function and estimating behavioral thresholds.
Assuntos
Acústica , Cóclea/fisiopatologia , Perda Auditiva Neurossensorial/fisiopatologia , Emissões Otoacústicas Espontâneas , Processamento de Sinais Assistido por Computador , Estimulação Acústica , Adolescente , Adulto , Idoso , Audiometria de Tons Puros , Percepção Auditiva , Estudos de Casos e Controles , Feminino , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Dinâmica não Linear , Pessoas com Deficiência Auditiva/psicologia , Psicoacústica , Fatores de Tempo , Adulto JovemRESUMO
Analytes that co-elute and yield nearly identical electron ionization (EI) mass spectra, as well as analytes that yield non-specific EI fragmentation patterns, have been identified using fully integrated gas chromatography with direct deposit Fourier transform infrared detection and mass spectrometric detection (GC/FT-IR/MS). While the IR detector proved to be more selective for identifying analytes such as synthetic cannabinoids and weight loss drugs, it was limited by a relatively high detection limit of 8.4 parts per million (ppm) for non-targeted identification of sibutramine based on a single injection but was reduced to 840 parts per billion (ppb) for targeted identification of sibutramine by redepositing ten injections along the same track. The MS detector was less selective for identifying these analytes but yielded non-targeted and targeted detection limits of approximately 84 ppb and 8.4 ppb, respectively, which corresponded to a 100-fold advantage compared to the IR detector. Overall, the results of this study demonstrate that the advantages of each detector compensate for the limitations of the other, which allows a wider range of analytes and concentrations to be examined using a fully integrated GC/FT-IR/MS instrument compared to what can be examined using GC/IR or GC/MS independently. Not only does this approach reduce consumption of laboratory resources and time, it provides IR and MS information on the same sample, which is important for forensic analyses that require data from two or more orthogonal techniques to make an identification.
RESUMO
A screen for known PDE-5 inhibitors in a dietary supplement product marketed for "enhanced sexual performance" detected a compound that structurally resembled chloropretadalafil, a known analog of tadalafil. The compound was isolated from the supplement matrix using high performance liquid chromatography with ultraviolet detection (HPLC-UV) and a fraction collector, and was further characterized using gas chromatography with Fourier Transform infrared detection and mass spectral detection (GC/FT-IR/MS), as well as high resolution mass spectrometry (HRMS). The analog had an accurate mass of m/z 441.1216 (error is 0.8706ppm) for the protonated species [M+H](+), corresponding to a molecular formula of C23H22ClN2O5. HRAM and GC/FT-IR/MS mass spectral fragmentation data suggested that the modification is a chloropropanoyl moiety extending from the nitrogen on the piperidine ring of chloropretadalafil. The proposed new analog has been named chloropropanoylpretadalafil.
Assuntos
Suplementos Nutricionais/análise , Tadalafila/análogos & derivados , Cromatografia Líquida de Alta Pressão , Cromatografia Gasosa-Espectrometria de Massas , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Tadalafila/análise , Tadalafila/isolamento & purificaçãoRESUMO
The triple-helical structure of a model collagen peptide possessing azobenzene-derived clamps integrated in all three strands as side-chain-to-side-chain crosslinks is analyzed by IR spectroscopy in comparative thermal excursion experiments with the triple helix of a typical reference collagen peptide consisting of only glycine-proline-hydroxyproline repeats. By exploiting the known stabilizing effects of aqueous alcoholic solvents on the unique collagen fold, deuterated ethylene glycol/water (1:1) is used as a solvent to investigate the effect of the light-switchable trans/cis-azobenzene clamp on the stability of the triple helix in terms of H/D exchange rates and thermal unfolding. Results of this comparative analysis clearly reveal only a minor destabilization of the triple helix by the hydrophobic azobenzene moieties compared to the reference collagen peptide as reflected by a lower midpoint of the thermal unfolding and higher rates of H/D exchange. However, it also reveals that the driving force exerted by the trans-to-cis photoisomerization of the azobenzene moieties is insufficient for unfolding of the compact triple-helical collagen fold. Only temperature-dependent untightening of this fold with heating results in a reversible photomodulated unfolding and refolding of the azo-collagen peptide into the original triple helix.