Direct determination of fluoride in sea water with a fluoride selective ion electrode by a method of standard additions

A newly developed method of background correction for atomic absorption spectrometry combined with the Varian Techtron carbon rod atomizer, model 63, has been applied to the direct determination of Pb, Zn, Fe, Cu, Ni, Co, and Cd in sea water. The background-corrected absorption measurements are reproducible and have a linear relationship to increasing additions of the metal over the ranges examined for the direct determination of metals in sea water. The values are comparable to those obtained by the accepted ammonium tetramethylenedithiocarbamate-methyl isobutyl ketone flame atomic absorption spectrometry method, within the limits of precision expected. However, except for Fe and Zn, the method is not sensitive enough to allow measurements at the lower concentration ranges of the metals in sea water. The direct method is a rapid technique for analyzing marine waters enriched in metals.

Download Full-text

An Indirect Atomic Absorption Spectrometric Determination of Trifluoperazine Hydrochloride in Pharmaceutical Formulations Based on Chelate Formation with Palladium(II)

E-Journal of Chemistry ◽

10.1155/2010/153861 ◽

2010 ◽

Vol 7 (s1) ◽

pp. S433-S441

Author(s):

Ameen W. Qasim ◽

Zuhair A. A. Khammas

Keyword(s):

Atomic Absorption ◽

Direct Determination ◽

Pharmaceutical Formulations ◽

Mean Value ◽

Pharmaceutical Dosage Form ◽

Accuracy And Precision ◽

Standard Additions ◽

Optimized Conditions ◽

Atomic Absorption Spectrometric

A new application of an indirect atomic absorption spectrometric (AAS) method was offered for the assay of low concentration of trifluoperazine hydrochloride (TFPH) in pure and pharmaceutical dosage form with good accuracy and precision. The method is depended on the formation of metal complex between the drug (TFPH) and palladium(II) to form orange-yellowish product extractable in organic solvent prior to its aspiration into an air-acetylene flame and indirectly determined by AAS. Using AA responses, all experimental parameters such as, pH, concentration of palladium, reaction time, extraction time and phase ratio which affect the complexation and extraction of TFPH-Pd(II), have been investigated. Under optimized conditions, linearity was observed in the range of 0.5-17 μg mL-1with detection limit (S/N) of 0.038 μg mL-1, precision in range of 1.18-1.92%, accuracy as the %Erelof 2.4% and recoveries ranged from 101.7 to 104% with mean value of 102.4±0.135. The proposed method was applied for the determination of TFPH in the drug stelazine by both direct calibration and standard additions procedures and found to be 4.88 and 4.87 mg per unite, respectively compared with the stated value of 5 mg per unite. This method is also compared statistically with direct determination by using UV-Vis spectrophotometric technique which is preformed in our laboratory and found to be insignificant at 95% confidence level. All statistical calculations were implemented via the chemsoftware Minitab version 11.

Download Full-text