|
|
|
|
|
SANTOS,QUEILA O.; MORENO,ISLANIA; SANTOS,LEANDRO DOS; SANTOS,ALDENOR G.; SOUZA,VALDINEI S.; BEZERRA,MARCOS A.. |
A modified simplex algorithm was used to optimize a system of preconcentration for cadmium determination in samples of sediments, cigarettes and food using flame atomic absorption spectrometry. The preconcentration system is based on the sorption of cadmium in a minicolumn packed with Amberlite XAD-2 resin functionalized with 3,4-dihydroxybenzoic acid (DHB). The optimized variables were pH and sampling flow rate and the optimum conditions found for these variables were, respectively 8.7 and 8.8 mL min-1. The developed system showed a preconcentration factor of 15.3, detection limit of 0.49 µg L-1, quantification limit of 1.65 µg L-1 and precision expressed as relative standard deviation (% RSD, n=10) of 5.9. The accuracy of the method was checked by... |
Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Simplex optimization; Preconcentration; Cadmium; Sediments; Cigarettes; Food. |
Ano: 2016 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000300791 |
| |
|
| |
|
| |
|
|
Blaine, Thomas W.; Reed, Michael R.. |
A framework was developed in order to specify a model for annual U.S. per capita consumption of cigarettes. Three separate time related variables were utilized to measure the effects of health related information regarding smoking. The empirical results from the post World War II data set reveal that while prices and income are important determinants of cigarette consumption, the estimates for both were in the inelastic range. The age distribution of the adult population is also an important variable. While the development of the filter tip has been successful in stimulating smoking, the low tar and nicotine innovation has not had a statistically significant effect. Health information has repeatedly produced substantial short and long run effects.... |
Tipo: Journal Article |
Palavras-chave: Cigarettes; Demand; Elasticity; Empirical estimation; Health Economics and Policy. |
Ano: 1994 |
URL: http://purl.umn.edu/15181 |
| |
|
|
|