scholarly journals OPTIMIZATION OF SAMPLE PREPARATION FOR THE DETERMINATION OF HPA'S VISION IN A GEOMETRIC TECHNIQUE USING MOLECULAR FLUORESCENCE

2012 ◽  
Vol 09 (18) ◽  
pp. 65-70
Author(s):  
Andréa Francisca Fernandes BARBOSA ◽  
Dayanne Chianca MOURA ◽  
Fabiana Roberta Gonsalves da Silva HUSSEIN ◽  
Jailson Vieira MELO ◽  
Djalma Ribeiro SILVA

The sample preparation is considered an essential step in the analysis process. The complexity of the matrix and how the compounds are linked is one of the main difficulties in the extraction. Thus a solvent system combined with an extraction method, both need to be effective against such mishaps. In this work we used the 23 factorial design to determine the optimum conditions for sample preparation. The analysis of the samples were performed in a molecular fluorescence spectrophotometer. The factors selected to investigate the influence on the extraction system were: time of use of ultrasound, the type of solvent (hexane or dichloromethane) and ratio solvent / sample (1:1 and 1:3). The best result was obtained with using the dichloromethane in time of 10 min of ultrasound and the ratio solvent / sample 1:3.

2013 ◽  
Vol 10 (19) ◽  
pp. 6-11
Author(s):  
Andréa Francisca Fernandes BARBOSA ◽  
Dayanne Chianca MOURA ◽  
Fabiana Roberta Gonsalves da Silva HUSSEIN ◽  
Jailson Vieira MELO ◽  
Djalma Ribeiro SILVA

The sample preparation is considered an essential step in the analysis process. The complexity of the matrix and how the compounds are linked is one of the main difficulties in the extraction. Thus a solvent system combined with an extraction method, both need to be effective against such mishaps. In this work we used the 23 factorial design to determine the optimum conditions for sample preparation. The analysis of the samples were performed in a molecular fluorescence spectrophotometer. The factors selected to investigate the influence on the extraction system were: time of use of ultrasound, the type of solvent (hexane or dichloromethane) and ratio solvent / sample (1:1 and 1:3). The best result was obtained with using the dichloromethane in time of 10 min of ultrasound and the ratio solvent / sample 1:3.


2016 ◽  
Vol 8 (1) ◽  
pp. 37-46
Author(s):  
Brankica Kartalović ◽  
Željko Mihaljev ◽  
Nadežda Prica ◽  
Sandra Jakšić ◽  
Milica Živkov Baloš ◽  
...  

Validation of analytical methods ensures the reliability and accuracy of analytical results. To get a reliable result we performed a validation ofthe method taking into account all factors that may aff ect of the result. In this paper we optimized QuEChERS method for food and feed sample preparation as well as instrumental method using gas chromatography with mass spectrometry (GC-MS), and we obtained a method for successful determination of pesticides with calibration through the matrix. In this way, applying calibration through matrix, we satisfi ed the requirements for precision and reproducibility of the method being less than 20%, the accuracy rate in the range of 70-130% and method linearity throughout the range of interest.


1980 ◽  
Vol 24 ◽  
pp. 393-398 ◽  
Author(s):  
John J. LaBrecque

SummaryAn improved method for sample preparation and determination of minor elements in catalytic materials by radioisotope induced X-ray fluorescence is presented. The sample preparation is simple and rapid, it utilizes both and internal standard procedure as well as a thin film technique. Synthetic standards are prepared simply by mixing thoroughly the appropriate amounts of the elements of interest as their respective oxides with the matrix and the internal standard. The above standards are used to calculate the relative-fluorescence ratio factors (FJL) for each element of interest relative to the internal standard.Some of the different types of deviations (sample preparation, standard counting, instrumental, etc) will be shown for typical determinations applying experimental methods. Finally the application of this technique for the determination of Cobalt, Nickel, Molybdenum, Platinum and Palladium in catalytic materials is presented.


Author(s):  
H.J. Dudek

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S


Author(s):  
Dr. G. Kaemof

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.


Author(s):  
C.T. Hu ◽  
C.W. Allen

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.


Author(s):  
Hind Hadi ◽  
Gufran Salim

A simple, rapid and sensitive spectrophotmetric method for trace determination of salbutamol (SAL) in aqueous solution and in pharmaceutical preparations is described. The method is based on the diazotization coupling reaction of the intended compound with 4-amino benzoic acid (ABA) in alkaline medium to form an intense orange, water soluble dye that is stable and shows maximum absorption at 410 nm. A graph of absorbance versus concentration indicates that Beer’s law is obeyed over the concentration range of 0.5-30 ppm, with a molar absorbtivity 3.76×104 L.mol-1 .cm-1 depending on the concentration of SAL. The optimum conditions and stability of the colored product have been investigated and the method was applied successfully to the determination of SAL in dosage forms.


Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.


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