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Determinating trace amounts
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A new spectrophotometric method for determinating trace amounts of fluoride has been introduced in this article. The principle of the method is based on the reaction of fluoride with a complex of aluminum ion and xylenol orange reagent (Al-XO).
5p
vichristinelagarde
04-07-2022
8
1
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The procedure is simple: to a known amount of sulfite in the polarographic cell (HAc, pH 6 or 7) is added an unknown Hg(II) sample. The Hg(II) concentration is calculated simply from the decrease in the sulfite peak after reaction with Hg(II). The limit of detection was 1 × 10 −6 M (S/N = 3) in this medium, which could not be obtained with most other mercury determination methods. The proposed new method exhibits high selectivity, sensitivity, reproducibility, and accuracy.
9p
langthannam
29-12-2021
8
0
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Cloud point extraction (CPE), which is the most popular coacervate-based extraction method, was utilized for the separation and preconcentration of trace amounts of cadmium, lead, and nickel. Quinalizarin was used as complexing agent and Triton X-114 was used as surfactant. After extraction, analyte ions were determined by flame atomic absorption spectrometry. The detection limits (3 s) of 1.8 µg L −1 for Cd(II), 3.2 µg L −1 for Pb(II), and 2.8 µg L −1 for Ni(II) were obtained using 50 mL of solutions.
9p
langthannam
29-12-2021
13
0
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Liquid phase microextraction (LPME) procedures have been widely used in combination with atomic and emission spectroscopic techniques for the isolation and preconcentration of trace elements. However, its application in combination with total reflection X-ray spectrometry (TXRF) is still scarce. In this paper, we evaluate the possibilities and drawbacks of a two-phase hollow fiber LPME procedure in combination with TXRF for the simultaneous determination of trace amounts of Cr, Ni, Cu, Zn, Pb, and Cd in aqueous samples.
11p
langthannam
29-12-2021
9
0
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A supramolecular solvent microextraction procedure was established for the separation/preconcentration of uranium(VI) (U(VI)) prior to its determination by UV-Vis spectrophotometry. 1-(2-Pyridylazo)-2-naphthol (PAN) was used to form a red chelate (U-PAN) with U(VI) at pH 10. U-PAN was extracted by undecanol in tetrahydrofuran. All the parameters that affect extraction efficiency like solution pH, amount of ligand, type and volume of supramolecular solvent, sample volume, and diverse ion effect were optimized.
9p
langthannam
29-12-2021
4
0
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Immediate preconcentration and spectrophotometric methods have been developed for the determination of trace amounts of cupric ion (Cu(II)) and nickel ion (Ni(II)) through a solid phase extraction with XAD-4-N,N’-bis- (salicylidene) cyclohexanediamine (XAD-4-SCHD) resin and a complex color reaction of the ions with 2,6-dimethylmorpholine dithiocarbamate (DMMDTC) in Triton X-100 media. A high preconcentration factor of 125 was achieved.
11p
tudichquannguyet
29-11-2021
3
1
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A new sensitive and accurate solid-phase extraction method for preconcentration of trace amounts of cadmium and lead in various environmental samples prior to flame atomic absorption spectrometry determination has been developed. The proposed method is based on the utilization of multiwalled carbon nanotubes in combination with 5-benzyl-4-[-chlororbenzylidene amine]-4H-1,2,4-triazole-3-thiol (BCBATT) as a solid-phase sorbent with the aid of ultrasonication. The effect of the preconcentration parameters was investigated.
14p
tudichquannguyet
29-11-2021
5
1
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A method for preconcentration of Al(III) prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed because the sensitivity of ICP-OES is insufficient for trace-level measurement of Al(III). The method is based on the use of Coriolus versicolor-immobilized γ-Fe2O3 magnetic nanoparticles as a solid phase sorbent. The best experimental conditions were found as pH 6.0, 2.0 mL/min flow rate, 100 mg amount of C. versicolor on 150 mg of γ-Fe2O3 nanoparticles, and 500 mL of sample volume. The Al(III) absorbed on biosorbent was eluted with 5.
12p
tudichquannguyet
29-11-2021
12
1
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The current work deals with fabrication and validation of a new highly Fe3+ selective sensor based on benzo-18crown-6 (b-18C6) using the potentiometric method. The proposed sensor revealed satisfactory performance for quantitative evaluation of Fe3+ trace amount in environmental samples.
12p
vijiraiya2711
27-05-2020
14
0
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Harrison's Internal Medicine Chapter 70. Nutritional Requirements and Dietary Assessment Nutritional Requirements and Dietary Assessment: Introduction Nutrients are substances that must be supplied by the diet because they are not synthesized in the body in sufficient amounts. Nutrient requirements for groups of healthy persons have been determined experimentally. For good health we require energy-providing nutrients (protein, fat, and carbohydrate), vitamins, minerals, and water.
5p
konheokonmummim
03-12-2010
88
7
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