RI UFBA >
Instituto de Química >
Artigos Publicados em Periódicos (Quimica) >
Please use this identifier to cite or link to this item:
|Title: ||Application of three-variables Doehlert matrix for optimisation of an on-line pre-concentration system for zinc determination in natural water samples by flame atomic absorption spectrometry|
|Other Titles: ||Microchemical Journal|
|Authors: ||Santos, Walter Nei Lopes dos|
Santos, Carla M. C.
Ferreira, Sergio Luis Costa
|Keywords: ||Flame atomic absorption spectrometry (FAAS);Analysis of variance (ANOVA);Relative standard deviation|
|Issue Date: ||2003|
|Abstract: ||This article describes an on-line pre-concentration system for zinc determination in environmental samples by
flame atomic absorption spectrometry (FAAS).It was based on the sorption of zinc(II) ions in a minicolumn of
polyurethane foam loaded with 4-(2-pyridylazo)-resorcinol (PAR).The optimisation step was carried out using twolevel full factorial and a Doehlert design.Thr ee variables (sampling flow rate, buffer concentration and pH) were
regarded as factors in the optimisation.Results of the two-level full factorial design 23 for 8 runs (in duplicate) based on the Analysis of Variance (ANOVA) demonstrated that all the factors in the tested levels are statistically significant.Besides, the interaction (sampling flow rate=buffer concentration) was also statistically significant.A three-variables Doehlert design was applied in order to determine the best condition for pre-concentration and determination of zinc.
The validation process was assessed as: parameters of the analytical curve, precision, effect of other ions in the
proposed system, robustness test and accuracy.The proposed system allowed determination of zinc with detection
limit (3syS) of 0.28 mg ly1, and a precision (reproducibility), calculated as relative standard deviation (R.S.D.) of 10.0 and 3.7% for zinc concentration of 1.0 and 5.0 mg ly1, respectively.The achieved pre-concentration factor was 91.23 and the sampling frequency was 48 samples per hour. The achieved recovery for zinc determination in presence of several cations demonstrated that this procedure could be applied for analysis of water samples.The accuracy was confirmed by analysis of three certified reference materials.This procedure was applied for zinc determination in several kinds of water samples including saline aqueous waste from oil Refinery.|
|Description: ||Texto completo: acesso restrito. p. 211-221|
|Appears in Collections:||Artigos Publicados em Periódicos (Quimica)|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.