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1.
Rapid Commun Mass Spectrom ; 35(17): e9141, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34106497

RESUMO

RATIONALE: The World Antidoping Agency (WADA) Monitoring program concentrates analytical data from the WADA Accredited Laboratories for substances which are not prohibited but whose potential misuse must be known. The WADA List of Monitoring substances is updated annually, where substances may be removed, introduced or transferred to the Prohibited List, depending on the prevalence of their use. Retroactive processing of old sample datafiles has the potential to create information for the prevalence of use of candidate substances for the Monitoring List in previous years. MetAlign is a freeware software with functionality to reduce the size of liquid chromatography (LC)/high-resolution (HR) full-scan (FS) mass spectrometry (MS) datafiles and to perform a fast search for the presence of substances in thousands of reduced datafiles. METHODS: Validation was performed to the search procedure of MetAlign applied to Anti-Doping Lab Qatar (ADLQ)-screened LC/HR-FS-MS reduced datafiles originated from antidoping samples for tramadol (TRA), ecdysterone (ECDY) and the ECDY metabolite 14-desoxyecdysterone (DESECDY) of the WADA Monitoring List. Searching parameters were related to combinations of accurate masses and retention times (RTs). RESULTS: MetAlign search validation criteria were based on the creation of correct identifications, false positives (FPs) and false negatives (FNs). The search for TRA in 7410 ADLQ routine LC/HR-FS-MS datafiles from the years 2017 to 2020 revealed no false identification (FPs and FNs) compared with the ADLQ WADA reports. ECDY and DESECDY were detected by MetAlign search in approximately 5% of the same cohort of antidoping samples. CONCLUSIONS: MetAlign is a powerful tool for the fast retroactive processing of old reduced datafiles collected in screening by LC/HR-FS-MS to reveal the prevalence of use of antidoping substances. The current study proposed the validation scheme of the MetAlign search procedure, to be implemented per individual substance in the WADA Monitoring program, for the elimination of FNs and FPs.


Assuntos
Anabolizantes/urina , Cromatografia Líquida/métodos , Dopagem Esportivo/métodos , Ecdisterona/urina , Espectrometria de Massas/métodos , Tramadol/urina , Dopagem Esportivo/prevenção & controle , Humanos , Urina/química
2.
Drug Test Anal ; 13(2): 460-465, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33119942

RESUMO

The current study examined the stability of several antidoping prohibited substances analytes in urine after 15-min exposure to UV-C light in a Biosafety Level 2 cabinet. The urine matrices were exposed within the original antidoping bottles with the aim to destroy DNA/RNA and possible SARS CoV-2. The analytes small molecules Phase I and Phase II metabolites and peptides, in total 444, endogenous, internal standards, and prohibited substances, pH, and specific gravity in urine were studied. The accredited analytical methods were used by Anti-Doping Laboratory Qatar for the comparison of data of the same urine samples analyzed with and without UV-C exposure. In the study conditions, no problems of stability were detected in the substances spiked in the urine samples exposed in the UV-C irradiation.


Assuntos
Anabolizantes/urina , Detecção do Abuso de Substâncias/métodos , Urinálise/métodos , Contenção de Riscos Biológicos/métodos , Dopagem Esportivo , Humanos , Raios Ultravioleta
3.
Steroids ; 152: 108477, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31446013

RESUMO

The population based Steroid Profile (SP) ratio of testosterone (T) and epitestosterone (E) has been considered as a biomarker approach to detect testosterone abuse in '80s. The contemporary Antidoping Laboratories apply the World Antidoping Agency (WADA) Technical Document (TD) for Endogenous Androgenic Anabolic Steroids (EAAS) in the analysis of SP during their screening. The SP Athlete Biological Passport (ABP) adaptive model uses the concentrations of the total of free and glucuronide conjugated forms of six EAASs concentrations and ratios measured by GC/MS. In the Antidoping Lab Qatar (ADLQ), the routine LC/MS screening method was used to quantitatively estimate the sulfate conjugated EAAS in the same analytical run as for the rest qualitative analytes. Seven sulfate EAAS were quantified for a number of routine antidoping male and female urine samples during screening. Concentrations, statistical parameters and selected ratios for the 6 EAAS, the 6 sulfate EAAS and 29 proposed ratios of concentrations from both EAAS and sulfate EAAS, which potentially used as SP ABP biomarkers, population reference limits and distributions have been estimated after the GC/MSMS analysis for EAAS and LC/Orbitrap/MS analysis for sulfate EAAS.


Assuntos
Esportes , Esteroides/urina , Detecção do Abuso de Substâncias , Sulfatos/urina , Atletas , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Valores de Referência
4.
Scand J Med Sci Sports ; 29(10): 1489-1500, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31206799

RESUMO

The aim of the present study was to investigate if hyperhydration could influence the excretion and subsequent detection of budesonide (BDS) and its main metabolites (6ß-hydroxy-budesonide and 16α-hydroxy-prednisolone) during doping control analysis by leading to concentrations below the WADA reporting level (30 ng/mL). The influence of hyperhydration on the plasma and urinary pharmacokinetic (PK) profiles of BDS and metabolites was also examined. Seven healthy physically active non-smoking Caucasian males participated in a 15-day clinical study. BDS was administered orally at a single dose of 9 mg on Days 1, 7, and 13. Hyperhydration was applied in the morning on two consecutive days, that is, 0 and 24 hours after first fluid ingestion. Water and a commercial sports drink were used as hyperhydration agents (20 mL/kg body weight). Results showed no significant difference (P > 0.05, 95% CI) on plasma or urinary PK parameters under hyperhydration conditions for all the analytes. However, significant differences (P < 0.05, 95% CI) due to hyperhydration were observed on the urinary concentrations of BDS and metabolites. To compensate the dilution effect due to hyperhydration, different adjustment methods were applied based on specific gravity, urinary flow rate, and creatinine. All the applied methods were able to adjust the concentration values close to the baseline ones for each analyte; however, specific gravity was the optimum method in terms of effectiveness and practicability. Furthermore, no masking of the detection sensitivity of BDS or its metabolites was observed due to hyperhydration either in plasma or urine samples.


Assuntos
Budesonida/farmacocinética , Ingestão de Líquidos , Estado de Hidratação do Organismo , Administração Oral , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Prednisolona/análogos & derivados , Prednisolona/sangue , Prednisolona/urina
5.
Rapid Commun Mass Spectrom ; 33(20): 1578-1588, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31240795

RESUMO

RATIONALE: Retroactive analysis of previously tested urine samples has become an important sports anti-doping tool. Retroactive reprocessing of old data files acquired from a generic screening procedure can reveal detection of initially unknown substances, like illegal drugs and newly identified metabolites. METHODS: To be able to efficiently search through hundreds to thousands of liquid chromatography high-resolution full-scan Orbitrap mass spectrometry data files of anti-doping samples, a combination of MetAlign and HR_MS_Search software has been developed. MetAlign reduced the data size ca 100-fold making possible local storage of a massive volume of data. RESULTS: The newly developed HR_MS_Search module can search through the reduced data files for new compounds (mass or isotope pattern) defined by mass windows and retention time windows. A search for 33 analytes in 940 reduced data files lasted 10 s. The output of the automatic search was compared to the standard manual routine evaluation. The results of searching were evaluated in terms of false negatives and false positives. The newly banned b2-agonist higenamine and its metabolite coclaurine were successfully searched in reduced data files originating from a testing period for which these substances were not banned, as an example of retroactive analysis. CONCLUSIONS: The freeware MetAlign software and its automatic searching module HR_MS_Search facilitated the retroactive reprocessing of reduced full-scan high-resolution liquid chromatography/mass spectrometry screening data files and created a new tool in anti-doping laboratories' network.


Assuntos
Agonistas Adrenérgicos beta/urina , Alcaloides/urina , Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Tetra-Hidroisoquinolinas/urina , Agonistas Adrenérgicos beta/metabolismo , Alcaloides/metabolismo , Dopagem Esportivo/prevenção & controle , Humanos , Isoquinolinas/urina , Detecção do Abuso de Substâncias , Tetra-Hidroisoquinolinas/metabolismo , Urinálise
6.
Molecules ; 23(7)2018 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-29954074

RESUMO

In this work a hydrophilic interaction liquid chromatography/positive ion electrospray mass spectrometric assay (HILIC/ESI-MS) has been developed and fully validated for the quantitation of metformin and rosuvastatin in human plasma. Sample preparation involved the use of 100 µL of human plasma, following protein precipitation and filtration. Metformin, rosuvastatin and 4-[2-(propylamino) ethyl] indoline 2 one hydrochloride (internal standard) were separated by using an X-Bridge-HILIC BEH analytical column (150.0 × 2.1 mm i.d., particle size 3.5 µm) with isocratic elution. A mobile phase consisting of 12% (v/v) 15 mM ammonium formate water solution in acetonitrile was used for the separation and pumped at a flow rate of 0.25 mL min−1. The linear range of the assay was 100 to 5000 ng mL−1 and 2 to 100 ng mL−1 for metformin and rosuvastatin, respectively. The current HILIC-ESI/MS method allows for the accurate and precise quantitation of metformin and rosuvastatin in human plasma with a simple sample preparation and a short a chromatographic run time (less than 15 min). Plasma samples from eight patients were further analysed proving the capability of the proposed method to support a wide range of clinical studies.


Assuntos
Cromatografia Líquida/métodos , Metformina/sangue , Rosuvastatina Cálcica/sangue , Espectrometria de Massas por Ionização por Electrospray/métodos , Humanos
7.
Talanta ; 183: 131-141, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29567155

RESUMO

A hydrophilic interaction liquid chromatography method with diode array detection (HILIC-DAD) was developed and validated for the simultaneous determination of impurities in extended-release fixed-dose combination tablets containing rosuvastatin and metformin in a ratio 1:100. The analytes were separated by hydrophilic interaction liquid chromatography using an XBridge®-HILIC analytical column under isocratic elution. The mobile phase was composed of ammonium formate at 150 mM containing 0.05% diethylamine (pH 8.5)/acetonitrile, 4/96 (v/v) and pumped at a flow rate of 0.5 mL min-1. Method validation was performed according to ICH guidelines. The calibration curves for rosuvastatin, metformin and their seven impurities showed good linearity (r > 0.994) within the calibration ranges tested. The intra- and inter-day R.S.D. values were less than 4.5%, while the relative percentage error Er was less than 2.7% for all compounds. Accelerated stability studies performed under various stress conditions including hydrolysis, oxidation and heat proved the selectivity of the procedure. A run time of less than 25 min for each sample made it possible to analyze a large number of samples per day. The method is the first reported application of HILIC for the analysis of impurities in fixed-dose combination tablets containing rosuvastatin and metformin and it can be used for the quality control of these drugs.


Assuntos
Contaminação de Medicamentos , Interações Hidrofóbicas e Hidrofílicas , Metformina/análise , Rosuvastatina Cálcica/análise , Cromatografia Líquida de Alta Pressão , Comprimidos/análise
8.
J Pharm Biomed Anal ; 151: 10-24, 2018 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-29291455

RESUMO

The aim of this paper is to present the development and validation of a high-resolution full scan (HR-FS) electrospray ionization (ESI) liquid chromatography coupled to quadrupole Orbitrap mass spectrometer (LC/Q/Orbitrap MS) platform for the screening of prohibited substances in human urine according to World Antidoping Agency (WADA) requirements. The method was also validated for quantitative analysis of six endogenous steroids (epitestosterone, testosterone, 5α-dihydrotestosterone, dehydroepiandrosterone, androsterone and etiocholanolone) in their intact sulfates form. The sample preparation comprised a combination of a hydrolyzed urine liquid-liquid extraction and the dilute & shoot addition of original urine in the extracted aliquot. The HR-FS MS acquisition mode with Polarity Switching was applied in combination of the Quadrupole-Orbitrap mass filter. The HR-FS acquisition of analytical signal, for known and unknown small molecules, allows the inclusion of all analytes detectable with LC-MS for antidoping investigations to identify the use of known or novel prohibited substances and metabolites after electronic data files' reprocessing. The method has been validated to be fit-for-purpose for the antidoping analysis.


Assuntos
Dopagem Esportivo/prevenção & controle , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos , Urinálise/métodos , Anabolizantes/urina , Cromatografia Líquida/métodos , Cromatografia Líquida/normas , Diuréticos/urina , Humanos , Espectrometria de Massas por Ionização por Electrospray/normas , Espectrometria de Massas em Tandem/normas , Urinálise/normas
9.
Drug Test Anal ; 9(7): 1062-1072, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27714984

RESUMO

The use of cephalosporins during breast feeding raises several issues, including the risk of drug exposure through breast milk for the infant. In this paper, a hydrophilic interaction liquid chromatography/positive ion electrospray mass spectrometric assay (HILIC/ESI-MS) was developed for the quantitation of cefuroxime, cefoxitin, and cefazolin in breast milk and human plasma. The assay was based on the use of small sample size, 25 µL of biological samples, following acetonitrile precipitation of proteins and filtration that enabled injection into the HILIC/ESI-MS system. All analytes and the internal standard, alfuzosin, were separated by using a ZIC®-HILIC analytical column (150.0 × 2.1 mm i.d., particle size 3.5 µm, 200 Å) with isocratic elution. The mobile phase was composed of a 6% 12.5 mM ammonium acetate water solution in acetonitrile and pumped at a flow rate of 0.25 mL min-1 . The assay was linear over a concentration range of 0.2 to 5 µg mL-1 and 0.4 to 20 µg mL-1 for all the analytes in breast milk and in human plasma, respectively. Intermediate precision was found to be less than 4.2% over the tested concentration ranges. A run time of less than 12 min for each sample made it possible to analyze a large number of biological samples per day. The method is the first reported application of HILIC in the analysis of antibiotics in breast milk and human plasma and it can be used to support a wide range of clinical studies. Copyright © 2016 John Wiley & Sons, Ltd.


Assuntos
Antibacterianos/análise , Antibacterianos/sangue , Leite Humano/química , Espectrometria de Massas por Ionização por Electrospray/métodos , beta-Lactamas/análise , beta-Lactamas/sangue , Cefazolina/análise , Cefazolina/sangue , Cefoxitina/análise , Cefoxitina/sangue , Cefuroxima/análise , Cefuroxima/sangue , Cromatografia Líquida/métodos , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção
10.
Artigo em Inglês | MEDLINE | ID: mdl-26432361

RESUMO

The concept of personalized medicine is related to the development of new sensitive, precise and accurate analytical methods for therapeutic drug monitoring. In this article a rapid, sensitive and specific method was developed for the quantification of aliskiren, losartan, valsartan and hydrochlorothiazide in human plasma. Sample preparation was performed by protein precipitation with acetonitrile followed by filtration. All analytes and the internal standard (tiamulin) were separated by hydrophilic interaction liquid chromatography using an X-Bridge-HILIC analytical column (150.0×2.1mm i.d., particle size 3.5µm) under isocratic elution. The mobile phase was composed of a 10% 5mM ammonium formate water solution pH 4.5, adjusted with formic acid, in acetonitrile and pumped at a flow rate of 0.25mLmin(-1). The assay was linear over the concentration range of 5-500ngmL(-1) for all the analytes. Intermediate precision was less than 5.2% over the tested concentration ranges. The method is the first reported application of HILIC in the analysis antihypertensives in human plasma. With a small sample size (50µL human plasma) and a run time less than 6.0min for each sample the method can be used to support a wide range of clinical studies and therapeutic drug monitoring.


Assuntos
Anti-Hipertensivos/sangue , Cromatografia Líquida/métodos , Monitoramento de Medicamentos/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Padrões de Referência
11.
Phytochemistry ; 108: 208-19, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25457502

RESUMO

The global metabolic profile of Laurencia crude red algal extracts was addressed by applying high-throughput analytical techniques, namely UHPLC­PDA­HRMS and 2D HSQC NMR. An integrated platform including software tools and databases, such as Xcalibur, ToxID, ACD/Labs and MarinLit, has been developed to mine the complex analytical data towards the accelerated identification of known metabolites and the detection of new natural products at the early stages of phytochemical analysis. In parallel, a searchable 'in-house' Laurencia-focused NMR database incorporating chemical structures, NMR spectroscopic data and reported biological activities has been generated. The screening strategy has been developed as a tool to prioritize the crude extracts to be further subjected to phytochemical analysis by tracing the presence of new natural products among the pool of known compounds. The successful application of this integrated methodology in the crude extract of Laurencia chondrioides led to the rapid detection of two new C15 bromoallene acetogenins (1 and 2), which were subsequently isolated and characterized.


Assuntos
Acetogeninas/isolamento & purificação , Produtos Biológicos/química , Hidrocarbonetos Bromados/isolamento & purificação , Laurencia/química , Acetogeninas/análise , Acetogeninas/química , Produtos Biológicos/análise , Produtos Biológicos/metabolismo , Hidrocarbonetos Bromados/análise , Hidrocarbonetos Bromados/química , Laurencia/metabolismo , Metabolômica , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular
12.
Bioanalysis ; 6(6): 881-96, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24702116

RESUMO

The abuse of unknown designer androgenic anabolic steroids (AAS) is considered to be an issue of significant importance, as AAS are the choice of doping preference according to World Anti-doping Agency statistics. In addition, unknown designer AAS are preferred since the World Anti-doping Agency mass spectrometric identification criteria cannot be applied to unknown molecules. Consequently, cheating athletes have a strong motive to use designer AAS in order to both achieve performance enhancement and to escape from testing positive in anti-doping tests. To face the problem, a synergy is required between the anti-doping analytical science and sports anti-doping regulations. This Review examines various aspects of the designer AAS. First, the structural modifications of the already known AAS to create new designer molecules are explained. A list of the designer synthetic and endogenous AAS is then presented. Second, we discuss progress in the detection of designer AAS using: mass spectrometry and bioassays; analytical data processing of the unknown designer AAS; metabolite synthesis; and, long-term storage of urine and blood samples. Finally, the introduction of regulations from sports authorities as preventive measures for long-term storage and reprocessing of samples, initially reported as negatives, is discussed.


Assuntos
Anabolizantes/metabolismo , Dopagem Esportivo/prevenção & controle , Esteroides/análise , Anabolizantes/administração & dosagem , Humanos
13.
J Chromatogr B Analyt Technol Biomed Life Sci ; 893-894: 114-20, 2012 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-22436822

RESUMO

A rapid hydrophilic interaction liquid chromatography/positive ion electrospray mass spectrometric assay (HILIC/ESI-MS) was developed, validated and applied to the determination of deferasirox, in human plasma. The sample preparation process involved liquid-liquid extraction of 50 µL plasma sample using ethyl acetate as an extraction solvent. Chromatographic separation was performed on an XBridge-HILIC analytical column (150.0 mm × 2.1 mm i.d., particle size 3.5 µm, 135 Å) under isocratic elution. The mobile phase was composed of a 10% 8.0 mM ammonium acetate water solution pH=5.0, adjusted with formic acid, in a binary mixture of acetonitrile/methanol (50:50, v/v) and pumped at a flow rate of 0.20 mL/min. Quantitation of deferasirox was performed with selected ion monitoring (SIM) in positive ionization mode using electrospray ionization interface. The assay was found to be linear in the concentration range of 0.20-120.0 µg/mL for deferasirox. Intermediate precision was found less than 3.9% over the tested concentration ranges. A run time of less than 6.0 min for each sample made it possible to analyze a large number of human plasma samples per day. The method can be used to support a wide range of clinical studies concerning deferasirox monitoring and it was applied to the analysis of human plasma samples obtained from patients with ß-thalassemia major.


Assuntos
Benzoatos/sangue , Cromatografia Líquida/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Triazóis/sangue , Acetatos , Acetonitrilas , Adulto , Deferasirox , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Modelos Lineares , Masculino , Metanol , Mianserina/análogos & derivados , Mianserina/sangue , Mirtazapina , Talassemia beta/sangue
14.
Rapid Commun Mass Spectrom ; 21(15): 2439-46, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17610244

RESUMO

A new combined doping control screening method for the analysis of anabolic steroids in human urine using liquid chromatography/electrospray ionization orthogonal acceleration time-of-flight mass spectrometry (LCoaTOFMS) and gas chromatography/electron ionization orthogonal acceleration time-of-flight mass spectrometry (GCoaTOFMS) has been developed in order to acquire accurate full scan MS data to be used to detect designer steroids. The developed method allowed the detection of representative prohibited substances, in addition to steroids, at concentrations of 10 ng/mL for anabolic agents and metabolites, 30 ng/mL for corticosteroids, 500 ng/mL for stimulants and beta-blockers, 250 ng/mL for diuretics, and 200 ng/mL for narcotics. Sample preparation was based on liquid-liquid extraction of hydrolyzed human urine, and the final extract was analyzed as trimethylsilylated derivatives in GCoaTOFMS and underivatized in LCoaTOFMS in positive ion mode. The sensitivity, mass accuracy, advantages and limitations of the developed method are presented.


Assuntos
Anabolizantes/urina , Cromatografia Líquida de Alta Pressão/métodos , Drogas Desenhadas/análise , Dopagem Esportivo/prevenção & controle , Cromatografia Gasosa-Espectrometria de Massas/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Esteroides/urina , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
15.
J Mass Spectrom ; 41(5): 593-605, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16541390

RESUMO

A new method was developed and fully validated for the quantitation of benazepril, benazeprilat and hydrochlorothiazide in human plasma. Sample pretreatment was achieved by solid-phase extraction (SPE) using Oasis HLB cartridges. The extracts were analysed by high-performance liquid chromatography (HPLC) coupled to a single-quadrupole mass spectrometer (MS) with an electrospray ionization interface. The MS system was operated in selected ion monitoring (SIM) modes. HPLC was performed isocratically on a reversed-phase porous graphitized carbon (PGC) analytical column (2.1 x 125.0 mm i.d., particle size 5 microm). The mobile phase consisted of 55% acetonitrile in water containing 0.3% v/v formic acid and pumped at a flow rate of 0.15 ml min(-1). Chlorthalidone was used as the internal standard (IS) for quantitation. The assay was linear over a concentration range of 5.0-500 ng ml(-1) for all the compounds analysed, with a limit of quantitation of 5 ng ml(-1) for all the compounds. Quality control (QC) samples (5, 10, 100 and 500 ng ml(-1)) in five replicates from three different runs of analyses demonstrated intra-assay precision (coefficient of variation (CV) < or =14.6%), inter-assay precision (CV < or = 5.6%) and overall accuracy (relative error less than -8.0%). The method can be used to quantify benazepril, benazeprilat and hydrochlorothiazide in human plasma, covering a variety of pharmacokinetic or bioequivalence studies.


Assuntos
Anti-Hipertensivos/sangue , Benzazepinas/sangue , Cromatografia Líquida de Alta Pressão/métodos , Hidroclorotiazida/sangue , Espectrometria de Massas por Ionização por Electrospray/métodos , Anti-Hipertensivos/análise , Benzazepinas/análise , Calibragem , Cromatografia Líquida de Alta Pressão/normas , Humanos , Hidroclorotiazida/análise , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray/normas
16.
Anal Chim Acta ; 573-574: 284-90, 2006 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-17723535

RESUMO

A reversed-phase ion-pair high-performance liquid chromatographic method was developed and validated for the determination of magnesium ascorbyl phosphate and melatonin in cosmetic creams. The determination was performed on a BDS C 18 analytical column (250 x 4.6 mm i.d., 5 microm particle size); the mobile phase consisted of 0.020 M tetrabutylammonium hydroxide and 0.025 M potassium dihydrogen phosphate (pH 6.8) mixed with acetonitrile in a ratio (77:23, v/v) and pumped at a flow rate 1.00 ml min(-1). The UV detector was operated at 260 nm. The retention times of the magnesium ascorbyl phosphate, melatonin and chlorthalidone that was used as internal standard, were 6.55, 9.18 and 11.07 min, respectively. Calibration graphs are linear (r better than 0.9990, n=6), in concentration range 1.00-10.00 microg ml(-1) for magnesium ascorbyl phosphate and 0.63-6.25 microg ml(-1) for melatonin. The intra- and inter-day R.S.D. values were less than 6.0%, while the relative percentage error E(r) was less than 3.5% (n=5). The quantitation limits were 0.69 and 0.47 microg ml(-1), for magnesium ascorbyl phosphate and melatonin, respectively. The method was applied to the analysis of a cosmetic cream and proved to be suitable for rapid and reliable quality control.

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