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1.
Food Chem ; 317: 126428, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32113139

RESUMEN

During manufacturing processes and in the storage period of tea, amino acids may undergo enantiomeric isomerization, converting their l- to d-forms. To examine the hypothesis, a method was developed for the analysis of the enantiomers in tea leaves. After enriched by ion-exchange solid-phase extraction, the enantiomeric pairs were separated by a chiral high performance liquid chromatography (HPLC) and subsequently detected and identified by using a high resolution quadrupole time-of-flight mass spectrometry (QTOF MS). Only l-forms of amino acids were found in fresh tea leaves. A total of 11 d-amino acids were found in 19 tea samples, ranging from trace amount to 43 µg/g. The results indicated that the enantioisomerization of amino acids occurred in post-harvest tea leaves, and affected by process conditions and storage time.


Asunto(s)
Aminoácidos/análisis , Aminoácidos/química , Camellia sinensis/química , Análisis de los Alimentos/métodos , Hojas de la Planta/química , Té/química , Cromatografía Líquida de Alta Presión/métodos , Almacenamiento de Alimentos , Espectrometría de Masas , Sensibilidad y Especificidad , Extracción en Fase Sólida , Estereoisomerismo
2.
J Agric Food Chem ; 68(10): 3121-3131, 2020 Mar 11.
Artículo en Inglés | MEDLINE | ID: mdl-32053364

RESUMEN

A new method to simultaneously analyze various glucosinolates (GSLs) and isothiocyanates (ITCs) by reversed-phase ultra-high-performance liquid chromatography-electron spray ionization-tandem mass spectrometry has been developed and validated for 14 GSLs and 15 ITCs. It involved derivatization of ITCs with N-acetyl-l-cysteine (NAC). The limits of detection were 0.4-1.6 µM for GSLs and 0.9-2.6 µM for NAC-ITCs. The analysis of Sinapis alba, Brassica napus, and Brassica juncea extracts spiked with 14 GSLs and 15 ITCs indicated that the method generally had good intraday (≤10% RSD) and interday precisions (≤16% RSD). Recovery of the method was unaffected by the extracts and within 71-110% for GSLs and 66-122% for NAC-ITCs. The method was able to monitor the enzymatic hydrolysis of standard GSLs to ITCs in mixtures. Furthermore, GSLs and ITCs were simultaneously determined in Brassicaceae plant extracts before and after myrosinase treatment. This method can be applied to further investigate the enzymatic conversion of GSLs to ITCs in complex mixtures.


Asunto(s)
Brassicaceae/química , Cromatografía Líquida de Alta Presión/métodos , Glucosinolatos/química , Isotiocianatos/química , Extractos Vegetales/química , Sinapis/química , Espectrometría de Masas en Tándem/métodos , Cromatografía de Fase Inversa/métodos , Espectrometría de Masa por Ionización de Electrospray/métodos
3.
J Agric Food Chem ; 68(8): 2588-2596, 2020 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-32031793

RESUMEN

Monosaccharides play important roles in plant growth and development, and their biofunctions are closely related to their endogenous contents. Therefore, the determination of monosaccharides is beneficial for the further study of monosaccharide biofunction. In this work, we developed a liquid chromatography-mass spectrometry analytical method assisted by a post-column derivatization technique (LC-PCD-MS) for the fast and automatic determination of 16 monosaccharides in samples. Post-column chemical derivatization of monosaccharides was performed by a reaction of monosaccharides with 4-benzylaminobenzeneboronic acid (4-PAMBA) through boronate ester formation in a three-way connector. 4-PAMBA worked as a derivatization reagent to improve the selectivity and sensitivity of monosaccharide detection by MS. The developed LC-PCD-MS method integrates LC separation, chemical derivatization, and MS detection in one run, thus greatly reducing the analysis time for each sample. The limits of detection and limits of quantification for 16 monosaccharides were in the range of 0.002-0.1 and 0.007-0.5 ng/mL, respectively. Good linearity was obtained from the linear regression, with a determination coefficient (R2) ranging from 0.9928 to 1.0000. The relative recoveries were in the range of 80.7-117.8%, with the intra- and interday relative standard deviations less than 19.7 and 16.5%, respectively, indicating good accuracy and acceptable reproducibility of the method. Finally, the method was successfully applied to investigate the spatial and temporal distribution of 16 monosaccharides in the developing flower and germinating seed of Arabidopsis thaliana.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Monosacáridos/análisis , Espectrometría de Masas en Tándem/métodos , Arabidopsis/química , Arabidopsis/crecimiento & desarrollo , Arabidopsis/metabolismo , Cromatografía Líquida de Alta Presión/instrumentación , Flores/química , Flores/crecimiento & desarrollo , Flores/metabolismo , Límite de Detección , Monosacáridos/metabolismo , Semillas/química , Semillas/crecimiento & desarrollo , Semillas/metabolismo , Espectrometría de Masas en Tándem/instrumentación
4.
PLoS One ; 15(2): e0228822, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32032379

RESUMEN

A novel LC-MS/MS method was developed for the quantification of the new cyclin dependent kinase inhibitors (CDKIs) palbociclib and ribociclib and the aromatase inhibitor letrozole used in combinatory regimen. The proposed method is appropriate to be applied in clinical practice due to the simple and fast sample preparation based on protein precipitation, the low amount of patient sample necessary for the analysis (10 µL) and the total run time of 6.5 min. It was fully validated according to FDA and EMA guidelines on bioanalytical method validation. The linearity was assessed (R2 within 0.9992-0.9983) over the concentration ranges of 0.3-250 ng/mL for palbociclib, 10-10000 ng/mL for ribociclib and 0.5-500 ng/mL for letrozole that properly cover the therapeutic plasma concentrations. A specific strategy was implemented to reduce the carryover phenomenon, formerly known for these CDKIs. This method was applied to quantify the Cmin of palbociclib, ribociclib and letrozole in plasma samples from patients enrolled in a clinical study. The same set of study samples was analysed twice in separate runs to assess the reproducibility of the method by means of the incurred samples reanalysis. The results corroborated the reliability of the analyte concentrations obtained with the bioanalytical method, already proved by the validation process. The percentage differences were always within ±10% for all the analytes and the R2 of the correlation graph between the two quantifications was equal to 0.9994.


Asunto(s)
Aminopiridinas/sangre , Cromatografía Líquida de Alta Presión/métodos , Letrozol/sangre , Piperazinas/sangre , Purinas/sangre , Piridinas/sangre , Espectrometría de Masas en Tándem/métodos , Estabilidad de Medicamentos , Humanos , Reproducibilidad de los Resultados
5.
Food Chem ; 317: 126427, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32092611

RESUMEN

Determination of polyethylene terephthalate (PET) dimer up to heptamer 1st series cyclic oligomers, applying an LC-qTOF-MS method, has been developed and validated. Recoveries ranged between 80 and 112% with RSDs lower than 15%. An innovative semi-quantitative approach has been applied for 2nd and 3rd series cyclic oligomers, using the closest structural-similar 1st series cyclic oligomer standard as analytical reference. Oligomers from the three series were quantified in PET teabags after migration experiments with water and food simulants C (20% v/v ethanol in water) and D1 (50% v/v ethanol in water). No legal migration limits exist currently for these substances. In silico genotoxicity assessment of all identified oligomers has been performed and showed no genotoxicity alert for linear or cyclic molecules. Exposure assessment was performed using EFSA's approach on the total sum of migrating oligomers and on toxicological threshold-of-concern. Amounts found in water were in some cases significantly higher than the respective limits, especially in the worst-case scenario of multiple consumption.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Embalaje de Alimentos , Espectrometría de Masas/métodos , Tereftalatos Polietilenos/análisis , Tereftalatos Polietilenos/toxicidad , Simulación por Computador , Dimerización , Contaminación de Alimentos/análisis , Pruebas de Mutagenicidad , Tereftalatos Polietilenos/química , Reproducibilidad de los Resultados ,
6.
Chemosphere ; 250: 126199, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32092568

RESUMEN

As stand-alone approaches, chromatographic separations of arsenic in lichen using HPLC-ICP-MS or the use of sequential extractions have historically been shown to have low analyte recoveries and poor analyte selectivity respectively. This study modifies the first step of a sequential extraction with a chromatographic separation of five arsenic species using HPLC-ICP-MS, followed by a three-step sequential extraction and analysis with ICP-MS. The method was applied to lichens from a rural and urban site to demonstrate the applicability thereof, and the sum of arsenic concentrations from the extraction steps were compared to the total arsenic concentrations. Short term species stability of the As species in the lichen matrix was also evaluated over 1 month in the water-extractable fraction, where As species concentrations changed week by week, providing insight into biotransformation mechanisms. In the modified extraction step, dimethylarsinic acid (DMA) and arsenobetaine and an unknown As species (AsB + U1) were statistically (p < 0.05) higher in the urban site than the rural site. Analyte recoveries using the combined method were higher than other studies reported in literature, with percentage recoveries of 104% and 111% of As in the urban and rural sites respectively. Arsenic concentrations were found in the following order of abundance at both sites: oxidizable > reducible > water-extractable > residual. Concentrations of total As in the oxidizable and non-bioavailable fraction were statistically lower (p < 0.05) in the rural site than in the urban site. Based upon the information gained from this study, we could draw concise conclusions regarding the source apportionment, timing and the magnitude of the pollution event.


Asunto(s)
Arsénico/metabolismo , Contaminantes Ambientales/metabolismo , Líquenes/metabolismo , Arsénico/análisis , Arsenicales , Ácido Cacodílico/análisis , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas/métodos
7.
Artículo en Inglés | MEDLINE | ID: mdl-32004940

RESUMEN

Flibanserin (FLB) is the first FDA approved drug showed to have significant activity against sexual desire disorder of premenopausal and postmenopausal women. Unfortunately, FLB is used as an adulterant in dietary supplement products as a performance enhancer in sports. Identification of FLB and its metabolites in the biological samples requires an authenticated analytical technique. The aim of this study was to identify N-oxide metabolite of FLB in microsomal and S9 human liver enzyme fractions, rat urine and feces. There are several N-oxide reported as genotoxic impurity or reactive metabolites based on position of N-oxide in piperazine ring. This study also describes the strategy to utilize degradation chemistry for isolation of N-oxide and its step-wise characterization. An LC-MS method has been developed and employed for identifying the N-oxide metabolite of FLB. The targeted N-oxide metabolite in the extracted ion chromatogram of the in vitro and in vivo samples has been confirmed by analyzing the changes in observed mass at m/z 407.1693. Major distinguished abundant ions at m/z 243.1104, 190.0974, 161.0705, 119.0601 confirmed the structure of the metabolite. This study will help to understand the oxidative potential of FLB in toxicokinetic study. The developed method can be useful to identify FLB or its N-oxide metabolite in dope testing in future. This is the first time to report a strategy to utilize degradation chemistry for N-oxide metabolite characterization. In this study, isolated N-oxidative degradation product was used to confirm N-oxide metabolite which was characterized by LC-MS through H/D exchange and structure was ensured by NMR spectroscopy (1H, COSY).


Asunto(s)
Bencimidazoles , Medición de Intercambio de Deuterio/métodos , Heces/química , Espectrometría de Masas en Tándem/métodos , Administración Oral , Animales , Bencimidazoles/administración & dosificación , Bencimidazoles/análisis , Bencimidazoles/química , Bencimidazoles/metabolismo , Cromatografía Líquida de Alta Presión/métodos , Espectroscopía de Resonancia Magnética , Masculino , Oxidación-Reducción , Ratas , Ratas Sprague-Dawley
8.
Artículo en Inglés | MEDLINE | ID: mdl-32004941

RESUMEN

Despite the development of an off-line packed fiber solid phase extraction procedure (PFSPE) for urinary catecholamines, automation remains a challenge. Here, we propose an on-line PFSPE-HPLC procedure for automated sample processing and analysis of urinary catecholamines, with good recovery and precision, to avoid manual operation errors. The on-line PFSPE-HPLC procedure has been thoroughly optimized concerning the gradient, valve switch timing, the effects of complexing reagent and buffer solution, and the stability of the nanofibers. Validation of the developed on-line PFSPE-HPLC protocol in urine yielded satisfactory accuracies of 99.6-104.2%, precision below 7.0%, as well as a linear range from 1 ng/mL to 100 ng/mL with a correlation coefficient of 0.999. The developed protocol is herein presented as a potential technology for automated sample pretreatment for the determination of urinary catecholamines.


Asunto(s)
Catecolaminas/orina , Cromatografía Líquida de Alta Presión/métodos , Extracción en Fase Sólida/métodos , Automatización de Laboratorios , Catecolaminas/química , Catecolaminas/aislamiento & purificación , Éteres Corona/química , Humanos , Límite de Detección , Modelos Lineales , Nanofibras/química , Reproducibilidad de los Resultados
9.
Anal Bioanal Chem ; 412(7): 1685-1692, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32008083

RESUMEN

The 5α-reductase converts testosterone to dihydrotestosterone (DHT), and excess DHT could cause androgen-related diseases such as androgenetic alopecia and benign prostatic hyperplasia (BPH). To discover new 5α-reductase inhibitors, effective drug screening method with high throughput is thus essential. In this study, fully automated chip-based nanoelectrospray ionization-mass spectrometry (nano-ESI-MS) was innovatively utilized as a screening tool for 5α-reductase inhibitory assay in direct infusion mode, which simplified sample pretreatment and greatly improved experimental efficiency. The preliminary data indicated that curcumin, a natural anti-inflammatory compound, exhibited notably 5α-reductase inhibition activity. Moreover, the obtained results of the chip-based nano-ESI-MS were well consistent with those of HPLC-MS, which suggested that the chip-based nano-ESI-MS could be treated as a rapid and high-throughput drugs screening strategy in pharmaceutical development. Graphical abstract.


Asunto(s)
Inhibidores de 5-alfa-Reductasa/análisis , Ensayos Analíticos de Alto Rendimiento/métodos , Nanotecnología , Espectrometría de Masa por Ionización de Electrospray/métodos , Andrógenos/análisis , Automatización , Línea Celular Tumoral , Cromatografía Líquida de Alta Presión/métodos , Células HEK293 , Humanos , Masculino , Estándares de Referencia
10.
Biomed Chromatogr ; 34(4): e4804, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32012304

RESUMEN

Green TLC-densitometric and RP-HPLC methods were developed and validated for the determination of the active prodrug sulfasalazine (SZ), its active metabolite mesalazine (MZ) and the major active metabolite of mesalazine, N-acetyl-5-aminosalicylic acid (AS). In the developed TLC-densitometric method, chromatographic separation was carried out on TLC silica gel plates 60 F254 using a developing system consisting of ethyl acetate-methanol-ammonia solution 33% (8:2.5:0.3, by volume) and then scanning the separated bands at 215 nm using hydrochlorothiazide as an internal standard with linearity ranges of 0.4-3, 0.4-2.4 and 0.3-2 for SZ, MZ and AS, respectively. The developed RP-HPLC method depended on chromatographic separation using a C18 column with a solvent mixture of methanol-aqueous acetic acid solution (pH 5) as a mobile phase with gradient elution mode and UV scanning at 243 nm using pyrazinamide as internal standard with linearity ranges of 5-50, 5-40, and 3-20 for SZ, MZ and AS, respectively. US Food and Drug Administration guidelines were followed during validation of the methods. The greenness of the developed methods was estimated using the greenness profile and the Eco-Scale approach. Both methods passed the four quadrants of the greenness profile and had Eco-Scale score ˃75, thus they were considered to be green according to these approaches.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Cromatografía en Capa Delgada/métodos , Tecnología Química Verde/métodos , Sulfasalazina/sangre , Densitometría , Estabilidad de Medicamentos , Humanos , Modelos Lineales , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
11.
Biomed Chromatogr ; 34(4): e4807, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32020626

RESUMEN

Periplocae Cortex, named Xiang-Jia-Pi in China, has been widely used to treat autoimmune diseases, especially rheumatoid arthritis. However, the in vivo substances of Periplocae Cortex remain unknown yet. In this study, an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used for profiling the chemical components and related metabolites of Periplocae Cortex. A total of 98 constituents were identified or tentatively characterized in Periplocae Cortex: 42 C21 steroidal glycosides, 10 cardiac glycosides, 23 organic acids, 4 aldehydes, 7 triterpenes, and 12 other types. Among them, 18 components were unambiguously identified by comparison with reference standards. In addition, 176 related xenobiotics (34 prototypes and 142 metabolites) were screened out and characterized in rats' biosamples (plasma, urine, bile, and feces) after the oral administration of Periplocae Cortex. Moreover, the metabolic fate of periplocoside S-4a, a C21 steroidal glycoside, was proposed for the first time. In summary, phase II reactions (methylation, glucuronidation, and sulfation), phase I reactions (hydrolysis reactions, oxygenation, and reduction), and their combinations were the predominant metabolic reactions of Periplocae Cortex in rat. It is the first report to reveal the in vivo substances and metabolism feature of Periplocae Cortex. This study also provided meaningful information for further pharmacodynamics study of Periplocae Cortex, as well as its quality control research.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Medicamentos Herbarios Chinos/análisis , Medicamentos Herbarios Chinos/metabolismo , Espectrometría de Masas/métodos , Periploca/química , Administración Oral , Aldehídos/análisis , Aldehídos/química , Animales , Medicamentos Herbarios Chinos/administración & dosificación , Medicamentos Herbarios Chinos/química , Glicósidos/análisis , Glicósidos/química , Masculino , Corteza de la Planta/química , Raíces de Plantas/química , Ratas , Ratas Sprague-Dawley , Triterpenos/análisis , Triterpenos/química
12.
Clin Chim Acta ; 505: 31-33, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32084381

RESUMEN

BACKGROUND: Vitamin A and E are routinely monitored to assess nutritional status. The most commonly used approach for their measurement involves laborious liquid-liquid extraction followed by high-performance liquid chromatography (HPLC) analysis on dedicated instrumentation. We describe a simple, rapid protocol for measurement of vitamin A and E and their integration into an existing online sample preparation liquid chromatography tandem mass spectrometry (SPLC-MS/MS) workflow. METHODS: We performed a method comparison between the SPLC-MS/MS and HPLC methods for vitamin A and E by measuring patient specimens across the concentration range 11-81 µg/dL for vitamin A and 1-18 mg/L for vitamin E. The analysis times on each platform were also compared. RESULTS: SPLC-MS/MS and HPLC methods were comparable with regards to analytical performance; mean bias across the measured range was 2.54% (95% CL: -11.56-16.64%) for vitamin A and -2.04% (95% CL: -18.20-14.12%) for vitamin E. Total analysis times were 7 min and 15 min for SPLC-MS/MS and HPLC respectively. CONCLUSIONS: The development of a simplified sample preparation protocol and the use of multiplexing SPLC-MS/MS have reduced sample analysis times for vitamin A and E. This method has also optimized clinical workflow through consolidation of previously independent benches.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas en Tándem/métodos , Vitamina A/sangre , Vitamina E/sangre , 25-Hidroxivitamina D 2/análisis , Anticonvulsivantes/análisis , Busulfano/análisis , Humanos , Inmunosupresores/análisis , Laboratorios/organización & administración , Estándares de Referencia , Reproducibilidad de los Resultados , Flujo de Trabajo
13.
Artículo en Inglés | MEDLINE | ID: mdl-32062366

RESUMEN

Albendazole (ABZ) is the first-line drug in treating echinococcosis, which is recommended by WHO. To address the poor bioavailability of albendazole, liposomal albendazole was formulated and is available in our hospital for many years. In this study, a sensitive, reliable and accurate UPLC-Q-TOF-MS method was developed and validated for the determination of albendazole and its metabolites, albendazole sulfoxide (ABZSO), albendazole sulfone (ABZSO2) and albendazole-2-aminosulfone (ABZSO2NH2) in naturally echinococcus granulosus (E. granulosus) infected sheep plasma and tissues with mebendazole (MBZ) as the internal standard (IS). Plasma and tissues samples were prepared by protein precipitation method. The separation was performed on an ACQUITY UPLC® BEH C18 column (2.1 × 50 mm, 1.7 µm) with a gradient mobile phase consisting of methanol and water containing 0.1% formic acid at 0.4 mL/min. The detection was performed on a quadrupole time-of-flight (Q-TOF) high-resolution mass spectrometer using positive electrospray ionization (ESI) source with a chromatographic run time of 6.0 min. The detection was operated using target ions of [M + H]+ at m/z 266.096 for ABZ, m/z 282.091 for ABZSO, m/z 298.086 for ABZSO2, m/z 240.081 for ABZSO2NH2 and m/z 296.104 for IS in selective ion mode, respectively. This method was validated in terms of selectivity, linearity, precision, accuracy, recovery, matrix effect, dilution effect, carryover effects, stability, calibration curve and LLOQ. All validation parameter results were within the acceptable range described in guideline for bioanalytical method validation. This method has been successfully applied to the pharmacokinetic study following single and multiple oral dose of 10 mg/kg liposomal albendazole, and tissue distribution study following multiple oral dose of 10 mg/kg, with emulsion albendazole as the reference preparation. The results in the article will provide valuable information for use in clinical applications of liposomal albendazole and also be beneficial for further development of liposomal albendazole in future studies.


Asunto(s)
Albendazol/sangre , Albendazol/farmacocinética , Cromatografía Líquida de Alta Presión/métodos , Equinococosis/tratamiento farmacológico , Enfermedades de las Ovejas/tratamiento farmacológico , Albendazol/química , Albendazol/uso terapéutico , Animales , Equinococosis/veterinaria , Echinococcus granulosus , Modelos Lineales , Liposomas , Espectrometría de Masas/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Ovinos , Distribución Tisular
14.
Artículo en Inglés | MEDLINE | ID: mdl-32062368

RESUMEN

This study investigated lipid alterations in muscle tissues [gastrocnemius (Gas) and soleus (Sol)] of mice under different diet programs (weight gain, weight maintenance, weight regain, and controls) by nanoflow ultrahigh pressure liquid chromatography-electrospray ionization-tandem mass spectrometry. Since overloaded lipids in the skeletal muscle tissues by excessive fat accumulation are related to insulin resistance leading to type II diabetes mellitus, analysis of lipid alteration in muscle tissues with respect to high-fat diet (HFD) is important to understand obesity related diseases. A total of 345 individual lipid species were identified with their molecular structures, and 184 lipids were quantified by selected reaction monitoring method. Most triacylglycerol (TG) and phosphatidylethanolamine (PE) species displayed a significant (>2-fold, p < 0.01) increase in both the Gas and Sol and to a larger degree in the Gas. However, lipid classes involved in insulin resistance and anti-inflammatory response, including lysophosphatidylcholine (18:0), diacylglycerol (16:0_18:1, 16:0_18:2, and 18:1_18:1), ceramide (d18:1/24:0 and d18:1/24:1), and phosphatidylinositol (18:0/20:4), showed a significant accumulation in the Sol exclusively after HFD treatment. In addition, the lipid profiles were not significantly altered in mice that were fed HFD only for the last 4 weeks (weight gain group), suggesting that consuming HFD in the younger age period can be more effective in the Gas. This study reveals that lipid classes related to insulin resistance accumulated more in the Sol than in the Gas following HFD treatment and the weight regain program perturbed lipid profiles of the Sol to a greater extent than that by the other diet programs, confirming that the Sol tissue is more influenced by HFD than Gas.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Dieta Alta en Grasa , Lípidos/análisis , Músculo Esquelético/química , Espectrometría de Masas en Tándem/métodos , Animales , Límite de Detección , Masculino , Ratones , Ratones Endogámicos C57BL , Músculo Esquelético/metabolismo , Aumento de Peso/fisiología
15.
Artículo en Inglés | MEDLINE | ID: mdl-32065955

RESUMEN

Developing dissolution testing methods to measure the nicotine release profiles from smokeless tobacco products is valuable for product assessment and product-to-product comparisons. In this work, we developed a robust dissolution method to study the in vitro release of nicotine from smokeless tobacco products using the U.S. Pharmacopeia flow-through cell dissolution apparatus 4 (USP-4). We further developed and validated a sensitive Ultra Performance Liquid Chromatography coupled to Photodiode Array detector (UPLC-PDA) method for the accurate quantitation of the released nicotine into artificial saliva, which is our selected dissolution medium. We have successfully shown the applicability of the validated method by investigating the release profiles of nicotine from various commercial and CORESTA reference smokeless tobacco products [CRP 1.1 (Swedish-style snus pouch), CRP 2.1 (American-style loose moist snuff), CRP 4 (loose-leaf chewing tobacco) and CRP 4.1 (chopped loose-leaf chewing tobacco)]. Nicotine release profiles were analyzed by calculating the difference factor (f1) and similarity factor (f2) by adopting a methodology referenced in the Guidance for Industry from FDA's Center for Drug Evaluation and Research (CDER) and by fitting the release profile curves using a first order kinetic model. Nicotine release was found to be dependent on the form and cut of the smokeless tobacco products, with a slower release observed for snus and loose-leaf, compared to chopped and loose moist snuff smokeless tobacco. This dissolution methodology can be extended to measure and compare release of other constituents from smokeless tobacco products and has the potential for method standardization.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Nicotina/análisis , Tabaco sin Humo/análisis , Técnicas de Química Analítica/instrumentación , Técnicas de Química Analítica/métodos , Diseño de Equipo , Humanos , Límite de Detección , Modelos Lineales , Modelos Biológicos , Nicotina/farmacocinética , Reproducibilidad de los Resultados , Saliva/química
16.
Artículo en Inglés | MEDLINE | ID: mdl-32106061

RESUMEN

A comparative study was conducted to replace the traditional screening method (MFDS#83) with the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) EN method for the determination of 267 pesticides/metabolites/plant activators/growth regulators in five representative crop matrices (mandarin, pepper, potato, rice, and soybean). In the traditional method, samples were extracted with acetonitrile and salt, and purified with a solid-phase extraction cartridge. In the QuEChERS method, the sample extraction was carried out using acetonitrile and a mixture of salts, and purification was performed using dispersive solid phase extraction. The limit of quantification (LOQ) for the MFDS#83 method was 0.0004 mg/kg, whereas for the QuEChERS EN method, the LOQ varied from 0.002 to 0.006 mg/kg for all analytes in various matrices. A six-point matrix-matched calibration curve was prepared for all analytes in five matrices for both methods. Both the MFDS#83 and QuEChERS EN methods provided excellent linearity, with the coefficients of determination (R2) ≥ 0.99 for most of the compounds. In both cases, the method was validated in terms of recovery and repeatability after the fortification of two different concentrations with three replicates for each of the concentrations. The QuEChERS EN method provided better recovery than the MFDS#83 method for all matrices except mandarin.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Residuos de Plaguicidas/análisis , Espectrometría de Masas en Tándem/métodos , Verduras/química , Límite de Detección , Modelos Lineales , Residuos de Plaguicidas/química , Residuos de Plaguicidas/aislamiento & purificación , Reproducibilidad de los Resultados , Extracción en Fase Sólida/métodos
17.
Artículo en Inglés | MEDLINE | ID: mdl-32109747

RESUMEN

Cd(II) is toxic to many species, including humans, because it inactivates a number of enzymes and induces cytopathic effects in the liver, kidney, and skeletal tissues in humans. Metallothionein and glutathione (GSH) play a major role in the protection against Cd(II)-induced toxicity in mammalian cells. In this study, a relatively simple method for detecting trace amounts of Cd(II) chelators was developed by using 5,10,15,20-tetraphenyl-21H,23H-porphinetetrasulfonic acid (TPPS). The TPPS-Cd(II) complex was added to the elutions of high-performance liquid chromatography. The Cd(II) chelators separated by column chromatography were mixed with Cd(II)-bound TPPS (TPPS-Cd(II)). Cd(II) from TPPS-Cd(II) was chelated by the eluted Cd(II) chelators, resulting in the formation of free TPPS. The absorbance of TPPS shifted from 434 nm (TPPS-Cd(II)) to 414 nm (TPPS), and this characteristic shift was used to estimate the quantity and affinity of the Cd(II) chelators. This new method was compared with the bathocuproine disulfonate (BCS) method developed in our previous study. Instead of BCS-Cu(I), TPPS-Cd(II) was used as the colorimetric reagent. The experimental setup of the TPPS-based method is more general, and the preparation of the colorimetric solution is also much simpler than the BCS method. To verify the efficacy of this new method, we determined the actual Cd(II)-chelating ability of GSH in horse blood; the obtained concentration was in good agreement with the previously reported value.


Asunto(s)
Aporfinas/química , Cadmio/química , Quelantes/análisis , Quelantes/química , Cromatografía Líquida de Alta Presión/métodos , Animales , Glutatión , Caballos , Límite de Detección , Estrés Oxidativo
18.
Artículo en Inglés | MEDLINE | ID: mdl-32109749

RESUMEN

Obtaining longitudinal endocrinological data from free-ranging animals remains challenging. Steroid hormones can be extracted sequentially from non-invasively sampled biologically inert keratinous tissues, such as feathers, nails, hair and whiskers. However, uncertainty regarding the type and levels of steroids incorporated into such tissues complicates their utility in wildlife studies. Here, we developed a novel, comprehensive method to analyze fourteen C19 and fourteen C21 steroids deposited chronologically along the length of seal whiskers in a single, 6-minute chromatographic step, using ultra-performance convergence chromatography-tandem mass spectrometry. The limits of detection and quantification ranged from 0.01 to 2 ng/mL and from 0.1 to 10 ng/mL, respectively. The accuracy and precision were within acceptable limits for steroids at concentrations ≥2 ng/mL. The recovery (mean = 107.5% at 200 ng/mL), matrix effect and process efficiency of steroids evaluated, using blanked whisker matrix samples, were acceptable. The method was applied to the analysis of steroid hormone levels in adult female whisker segments obtained from southern elephant seals (Mirounga leonina), n = 10, and two fur seal species, Antarctic fur seals (Arctocephalus gazella; n = 5) and subantarctic fur seals (Arctocephalus tropicalis; n = 5), sampled between 2012 and 2017. In the whisker subsamples analyzed (n = 71), the median concentration of steroid hormones detected above the LOQ ranged from 2.0 to 273.7 pg/mg. This was the first extraction of multiple C19 and C21 steroids, including their C11-oxy metabolites, from the whiskers of mammals. Measuring hormones sequentially along the whisker lengths can contribute to our understanding of the impact of stress associated with environmental/climate changes that affect the health, survival of organisms, as well as to delineate the reproductive cycles of free-living mammals with cryptic life stages.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Esteroides/análisis , Espectrometría de Masas en Tándem/métodos , Vibrisas/química , Andrógenos/análisis , Animales , Femenino , Lobos Marinos , Glucocorticoides/análisis , Ensayos Analíticos de Alto Rendimiento , Límite de Detección , Modelos Lineales , Progestinas/análisis , Reproducibilidad de los Resultados
19.
Artículo en Inglés | MEDLINE | ID: mdl-32109750

RESUMEN

Di-n-butyl adipate (DnBA) is an alternative to the anti-androgenic and strictly regulated di-n-butyl phthalate (DnBP) used as a cosmetic ingredient, plasticizer, and in various articles of everyday life. Hence, exposures of the general population have to be expected. Currently, biomarkers of DnBA exposure and methods for their determination are not available. Here, we describe a sensitive, rugged and precise analytical method for the determination of the DnBA monoester metabolite mono-n-butyl adipate (MnBA), as well as its potential downstream metabolites 3-hydroxy-mono-n-butyl adipate (3OH-MnBA) and 3-carboxy-mono-n-propyl adipate (3cx-MnPrA) in human urine. Glucuronic acid conjugates present in urine were deconjugated using a pure ß-glucuronidase. The metabolites were then analyzed by liquid chromatography on a C18 column with superficially porous particles coupled to electrospray ionization-triple quadrupole-tandem mass spectrometry, applying online turbulent flow chromatography for analyte enrichment and matrix depletion (online-SPE-LC-MS/MS). The metabolites were quantified using stable isotope dilution analysis with limits of quantification of 0.05 µg/L (MnBA), 0.1 µg/L (3OH-MnBA), and 0.5 µg/L (3cx-MnPrA). Method imprecision in urinary matrix was below 7% (coefficient of variation) for all analytes. Mean relative recoveries were between 93% and 107%. The suitability of the DnBA metabolites as biomarkers of exposure was demonstrated after dermal application of a commercially available sunscreen containing DnBA. Maximum concentrations were reached 6.5 h after dose (219 µg/L 3cx-MnPrA, 91 µg/L MnBA, and 3.9 µg/L 3OH-MnBA). Elimination kinetics were similar for all three metabolites. We were able to quantify 3cx-MnPrA and MnBA until 4 d after sunscreen application. In a sample set of 35 urine samples from the general German population, 3cx-MnPrA was quantified in 94% (median 2.54 µg/L, maximum 78.3 µg/L) and MnBA in 3% (median < LOQ, maximum 0.18 µg/L) of the samples. The method will be applied in future human metabolism and human biomonitoring population studies.


Asunto(s)
Adipatos/orina , Cromatografía Líquida de Alta Presión/métodos , Extracción en Fase Sólida/métodos , Espectrometría de Masas en Tándem/métodos , Adipatos/aislamiento & purificación , Adulto , Biomarcadores/orina , Exposición a Riesgos Ambientales/análisis , Femenino , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto Joven
20.
Anal Bioanal Chem ; 412(8): 1807-1816, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32025771

RESUMEN

Herbal materials have both medicinal and commercial values. As such, accurate species and content identification and verification are necessary to ensure the safe and effective use for medical and commodity purposes. Herein, we introduce a two-step approach for systematic identification and quality evaluation of wild and introduced Anemone flaccida Fr. Schmidt (aka Di Wu) using DNA barcode and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS). To begin, a precise and rapid identification method based on internal transcribed spacer 2 (ITS2) sequence was developed to ensure the authenticity of 'Di Wu' species. Next, the major active components were fully characterized utilizing a targeted profile of oleanane-type triterpenoid saponins, which was established via UPLC-QTOF-MS/MS. As a result, 34 oleanane-type triterpenoid saponins were identified or characterized in 'Di Wu.' The qualitative and relative quantitative analysis showed obvious differences between wild and introduced 'Di Wu.' Furthermore, dynamic changes in the contents of triterpenoid saponins throughout various harvesting periods were clearly explained and mid-April was identified as the appropriate harvest time. Moreover, results indicate that the contents of five main saponins (anhuienoside E, glycosideSt-I4a, hemsgiganoside B, flaccidoside II, and hederasaponin B) are more appropriate as a quality evaluation indicator than the current quality standard. The two-step approach provides a suitable strategy to evaluate the genuine quality of wild and introduced 'Di Wu,' and can be applied to the targeted analysis of other triterpenoid saponin analogues for quality evaluation. Graphical Abstract .


Asunto(s)
Anemone/química , Cromatografía Líquida de Alta Presión/métodos , Código de Barras del ADN Taxonómico , Anemone/clasificación , Anemone/genética , Biomasa , Control de Calidad , Especificidad de la Especie , Espectrometría de Masas en Tándem
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