Determinação de cádmio em amostras de urina e soro humano por espectrometria de absorção atômica em forno de grafite usando irídio como modificador permanente
Abstract:Resumo:No presente estudo, foram investigadas diferentes substâncias para atuarem como modificadores químicos na determinação direta de cádmio em soro e urina humanos sem digestão prévia das amostras. A preparação da amostra foi feita diretamente nos copos do amostrador automático por diluição 1+4 de soro e 1+1 de urina com ácido nítrico 1% v/v contendo 0.02% v/v de cloreto de tricetil metil amônio (CTAC). Foram investigadas as melhores condições de determinação por meio de curvas de temperatura de pirólise e … Show more
“…Intra-and inter-assay precision was below the recommended values found in other studies for both analytes. [22][23][24]30 In this study we successfully demonstrated that there was no need for lengthy digestion prior to the analysis, which is subject to losses and contamination. Finally, the use of a permanent modier ensures the destruction of the matrix in situ providing the use of aqueous calibration, i.e.…”
Section: Discussionmentioning
confidence: 90%
“…The condition without the use of a modier was also studied. The lifetime of the graphite tube using a permanent modier without a decrease in sensitivity is more than 1000 cycles, 24,25 but was not investigated in this study.…”
Section: Methodsmentioning
confidence: 99%
“…All other tested modiers resulted in very low relative sensitivity. The diluent was selected as described by Pinto et al 24 in human serum and based on the results obtained for Bi, Cr and Al determinations in human serum samples. [27][28][29] Multivariate optimization…”
Section: Choice Of Diluents and Modiersmentioning
In this work efficient methods to determine copper and iron in dog serum samples by graphite furnace atomic absorption spectrometry were developed. The samples were diluted at a 1 : 9 or 1 : 19 (for Cu and Fe, respectively) ratio with 1% (v/v) nitric acid containing a 0.1% Triton X-100 solution. Rhodium for copper and no modifier for iron proved to be the better permanent modifier. Optimization included fractional factorial planning using Pareto and the CCD designs. For both analytes the working linear range was 0-100 mg L À1 (r 2 > 0.99). The obtained LOQ was 19.3 AE 2.8 mg L À1 for Cu and 16.5 AE 0.2 mg L À1 for Fe. Aqueous and matrix matching calibration curves had average angular coefficients that were not statistically different, i.e. the matrix effect was absent for both analytes. The accuracy was checked by recovery tests with an average of 101 AE 4% (n ¼ 45) for Cu and 90 AE 3% for Fe (n ¼ 45). The certified reference material SeronormÔ Trace Elements Serum L-1 obtained was 1705 AE 20 mg L À1 for Cu (certified: 1691 AE 84 mg L À1 ) and 1.40 AE 1.22 mg L À1 for Fe (certified: 1.43 AE 0.08 mg L À1 ). Cu and Fe levels in 39 canine serum samples -9 uninfected, 19 symptomatic and 11 asymptomatic dogs naturally infected with Leishmania chagasiranged from 374 to 913 mg L À1 , and 1103 to 4260 mg L À1 , respectively. Cu was higher in symptomatic than in asymptomatic and control dogs, and Fe was significantly lower in symptomatic than in either asymptomatic or control dogs.
“…Intra-and inter-assay precision was below the recommended values found in other studies for both analytes. [22][23][24]30 In this study we successfully demonstrated that there was no need for lengthy digestion prior to the analysis, which is subject to losses and contamination. Finally, the use of a permanent modier ensures the destruction of the matrix in situ providing the use of aqueous calibration, i.e.…”
Section: Discussionmentioning
confidence: 90%
“…The condition without the use of a modier was also studied. The lifetime of the graphite tube using a permanent modier without a decrease in sensitivity is more than 1000 cycles, 24,25 but was not investigated in this study.…”
Section: Methodsmentioning
confidence: 99%
“…All other tested modiers resulted in very low relative sensitivity. The diluent was selected as described by Pinto et al 24 in human serum and based on the results obtained for Bi, Cr and Al determinations in human serum samples. [27][28][29] Multivariate optimization…”
Section: Choice Of Diluents and Modiersmentioning
In this work efficient methods to determine copper and iron in dog serum samples by graphite furnace atomic absorption spectrometry were developed. The samples were diluted at a 1 : 9 or 1 : 19 (for Cu and Fe, respectively) ratio with 1% (v/v) nitric acid containing a 0.1% Triton X-100 solution. Rhodium for copper and no modifier for iron proved to be the better permanent modifier. Optimization included fractional factorial planning using Pareto and the CCD designs. For both analytes the working linear range was 0-100 mg L À1 (r 2 > 0.99). The obtained LOQ was 19.3 AE 2.8 mg L À1 for Cu and 16.5 AE 0.2 mg L À1 for Fe. Aqueous and matrix matching calibration curves had average angular coefficients that were not statistically different, i.e. the matrix effect was absent for both analytes. The accuracy was checked by recovery tests with an average of 101 AE 4% (n ¼ 45) for Cu and 90 AE 3% for Fe (n ¼ 45). The certified reference material SeronormÔ Trace Elements Serum L-1 obtained was 1705 AE 20 mg L À1 for Cu (certified: 1691 AE 84 mg L À1 ) and 1.40 AE 1.22 mg L À1 for Fe (certified: 1.43 AE 0.08 mg L À1 ). Cu and Fe levels in 39 canine serum samples -9 uninfected, 19 symptomatic and 11 asymptomatic dogs naturally infected with Leishmania chagasiranged from 374 to 913 mg L À1 , and 1103 to 4260 mg L À1 , respectively. Cu was higher in symptomatic than in asymptomatic and control dogs, and Fe was significantly lower in symptomatic than in either asymptomatic or control dogs.
“…The condition without modifier was also studied. The lifetime of the graphite tube using a permanent modifier without a decrease in sensitivity is more than 1000 cycles (11,(12)(13)(14); however, this was not investigated in this study.…”
In this work, efficient methods to determine aluminum (Al) and lead (Pb) in beer samples by graphite furnace atomic absorption spectrometry (GFAAS), following multivariate optimization, were developed. The only sample preparation used was degassing of the beer to remove CO 2. Permanent rhodium (Rh) for aluminum and permanent iridium (Ir) for lead proved to be the better permanent modifier. Optimization included fractional factorial planning using the Pareto and the CCD designs. The working linear range was 0-90 µg L-1 for aluminum and 0-60 µg L-1 for lead (r 2 >0.99). The obtained LOQs were 4.8 and 1.6 µg L-1 for aluminum and lead, respectively. Aqueous and matrix-matched calibration curves had average angular coefficients that were not statistically different, i.e., the matrix effect was absent for aluminum, while for lead the coefficients were statistically different. Matrix-matched calibration was used in the subsequent studies for the beer samples. The accuracy was checked by recovery tests with a percentage recovery range of 89-95% (n=45) for Al and 97 to 98% for Pb (n=45). The coefficient of variation (CV) of the intra-assay studies (n=15) was 4.0 and 2.5% for Al and Pb, respectively, where the CV for the inter-assay studies (n=45) was 3.0 for Al and 3.1% for Pb. The Al and Pb levels in the 21 beer samples varied from
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