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Submitted by Bruna Fernandes de farias (bruna.fernandes_farias@yahoo.com.br) on 2010-12-22T12:37:33Z No. of bitstreams: 1 2009_OliveiraSantosSantos.pdf.pdf: 234611 bytes, checksum: 82b656f0055b84584948aaaeaebb0408 (MD5) Approved for entry into archive by Claudia Araujo(caraujo@inmetro.gov.br) on 2011-03-31T20:59:48Z (GMT) No. of bitstreams: 1 2009_OliveiraSantosSantos.pdf.pdf: 234611 bytes, checksum: 82b656f0055b84584948aaaeaebb0408 (MD5) Made available in DSpace on 2011-03-31T20:59:48Z (GMT). No. of bitstreams: 1 2009_OliveiraSantosSantos.pdf.pdf: 234611 bytes, checksum: 82b656f0055b84584948aaaeaebb0408 (MD5) Previous issue date: 2009 Um procedimento espectrofotométrico de análise em fluxo foi desenvolvido para determinação de Captopril (CPT) e N-acetil-L-cisteína (NAC) em formulações farmacêuticas baseado na reação com radical iminoquinona produzido pela oxidação de N,N-dimetil-p-fenilenodiamina (DMPD) em meio ácido. A ordem de adição de reagentes foi avaliada e os parâmetros analíticos foram otimizados. As faixas lineares de concentração foram de 2,5-90 e de 5,0-50 mg L-1 para CPT e NAC, respectivamente. Os limites de detecção (3σ) foram calculados em 0,22 e 1,8 mg L-1 e desvios padrão relativos (N = 10) foram inferiores que 1,0 e 2,1% para CPT e NAC, respectivamente. O procedimento foi empregado para a determinação de CPT e NAC em diversas formulações farmacêuticas e os resultados concordaram com os obtidos pelos métodos de referência para 95% de confiabilidade aplicando teste-t pareado. ____________________________________________________________________________________. ABSTRACT - A spectrophotometric flow analysis procedure to determine Captopril (CPT) and N-acetyl-L-cysteine (NAC) in pharmaceutical formulations was developed based on the reaction with iminoquinone radical produced from the N,N-dimethyl-p-phenilenediamene (DMPD) oxidation in acid medium. The reagents addition order was evaluated and analytical parameters were optimized. The linear concentrations ranges were 2.5-90 and 5.0-50 mg L-1 for CPT and NAC, respectively. Limits of detection (3σ) were calculated at 0.22 and 1.8 mg L-1 and the relative standard deviation (N = 10) were lower than 1.0 and 2.1% for CPT and NAC, respectively. The procedure was employed for CPT and NAC determination in diverse pharmaceutical formulations and by applying paired t-test the results were in agreement with those obtained by reference methods for 95% confidence level. 7 p. : il.

In the present work a systematic comparison among spectrophotometric flow injection methods for sulfide determination based on phenothiazine dye production from diverse aromatic p -substituted amines were performed. The behavior of N , N -dimethylphenyl- p -diamine (DMPD), N , N -diethylphenyl- p -diamine (DEPD), phenyl- p -diamine (PPD), p -aminophenol (PAP) and other three aromatic amines was investigated and the chemical parameters of proposed flow methods were optimized by applying central composite design. For each evaluated method the concentration of amine, Fe 3+ and H 2 SO 4 was optimized and after the evaluation of reagents addition order the flow parameters were independently ascertained. Analytical signal was strongly diminished in the presence of iodide for flow methods based on the reaction of sulfide with DMPD, PPD or DEPD while fluoride was considered as an important interference for methods based on the reaction with PPD or PAP. The evaluated aromatic amines have permitted sulfide determination in a wide concentration range from 0.05 to 3.0 mg L − 1 and limits of detection (3 σ ) varying from 18.8 to 51.0 μg L − 1 , for DEPD and PPD, respectively. The sensitivity of flow methods based on PPD and DMPD was higher even as PAP has permitted sulfide determination in a large sulfide concentration range. In addition, higher throughput was attained for DMPD method. The proposed methods were applied for sulfide determination in industrial wastewater and the obtained results were in agreement with reference method at 95% confidence level.

The present article gives an overview of recent publications and modern techniques of sample preparation for food analysis employing atomic and inorganic mass spectrometric techniques, such as flame atomic absorption spectrometry, chemical vapor generation atomic absorption and atomic fluorescence spectrometry, graphite furnace atomic absorption spectrometry, inductively coupled plasma optical emission spectrometry, and inductively coupled plasma mass spectrometry. Among the most frequently applied sample preparation techniques for food analysis are dry ashing, usually with the addition of an ashing aid, and acid digestion, preferably with the assistance of microwave energy. Slurry preparation, particularly with the assistance of ultrasound, is increasingly used to reduce acid consumption and sample preparation time. Direct analysis of solid samples is gaining importance in the field of food analysis as it offers the highest sensitivity, avoids the use of acids and other aggressive reagents, make...