Quantitative determination of low concentrations of peptides in aqueous solutions by14C-labelling

1976 ◽  
Vol 32 (2) ◽  
pp. 447-459
Author(s):  
K. H. Standke
Keyword(s):  
Aqueous Solutions ◽  
Quantitative Determination ◽  
Low Concentrations

scholarly journals Recovery of Hg(0) from the Aqueous Hg(I/II) Present in Analyte Solution after Quantitative Determination of Iron

2013 ◽  
Vol 2013 ◽  
pp. 1-3
Author(s):  
Suman K. Giri ◽  
Nigamananda Das
Keyword(s):  
Aqueous Solutions ◽  
Quantitative Determination ◽  
Simple Method ◽  
Stoichiometric Amount ◽  
Analyte Solution

An easy and feasible approach to recover HgCl2, used in quantitative determination of iron values, as Hg(0) was described. Both Hg(I) and Hg(II), present in the solution after quantitative determination of iron, was completely reduced to Hg(0) by the addition of aluminium chips in more slightly excess than the stoichiometric amount. The purity of recovered Hg(0) was verified by comparing the value of density with pure mercury. This simple method may be useful to remove the mercury from other waste aqueous solutions before their discharge into the environment.

scholarly journals Biosafety Evaluation and Quantitative Determination of Poly(hexamethylene biguanide) (PHMB) Coated on Cellulosic Fabrics by Kubelka-Munk Equation

2021 ◽  
Author(s):  
Wen-Yi Wang ◽  
Jia-Chi Chiou ◽  
Wan-Xue Chen ◽  
Jia-Li Yu ◽  
Chi-wai Kan
Keyword(s):  
Quantitative Determination ◽  
Cotton Fabrics ◽  
Bromophenol Blue ◽  
Blue Dye ◽  
Feasible Method ◽  
Colour Strength ◽  
Low Concentrations ◽  
Cellulosic Fabric ◽  
Biosafety Evaluation

Abstract It is a challenge to determine the quantity of cationic finishing agents on the surface of cellulosic fabrics. Herein, we report a direct and feasible method by Kubelka-Munk equation to quantify the cationic poly (hexamethylene biguanide) hydrochloride (PHMB) adsorbed onto cotton fabrics based on the principle of formation of a stable blue dye between PHMB and bromophenol blue sodium (BPB). The adsorption of PHMB onto cotton fabrics was first investigated and the maximum adsorption of PHMB was found to be around 8 mg per gram of cotton fabric. After being dyed with BPB, colour strength shows a positive correlation with PHMB at low concentrations (< 2400 mg/L). A linear relationship with a high correlation (C(PHMB) = (K/S—0.7411)/3.4517, R2 = 0.9983) was thus established between colour strength and PHMB concentration. However, this equation should fulfill four requirements for quantifying PHMB: (1) the distribution of PHMB on the surface of cellulosic fabric should be in the form of a monolayer with the content less than 5.3 mg/g; (2) an excess of BPB dyebath should be applied; (3) the dyeing should come to equilibrium; and (4) the fabrics should be evenly dyed. Moreover, MTT assay results indicate that excess PHMB coated on cotton fabrics can cause cytotoxicity and the quantity of PHMB should not exceed 4.62 mg per gram of cotton fabrics for the purpose of biosafety. The sample can be considered non-cytotoxic if the K/S value is lower than 13.2 after dyeing with BPB.

Quantitative Determination of Cadmium in Water-Soluble Color Additives by Atomic Absorption Spectroscopy

1972 ◽  
Vol 55 (5) ◽  
pp. 1145-1149
Author(s):  
Lueangier Moten
Keyword(s):  
Aqueous Solutions ◽  
Quantitative Determination ◽  
Atomic Absorption ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Quantitative Method ◽  
Water Soluble ◽  
Low Levels ◽  
Absorption Measurements

Abstract A quantitative method is presented for the determination of cadmium at low levels (5–20 ppm) in water-soluble color additives by atomic absorption spectroscopy. Absorption measurements were made on aqueous solutions of typical color additives to which known amounts of cadmium had been added. The method requires no pretreatment of sample and should be applicable to all water-soluble color additives.

Methods for quantitative determination of ethylene in aqueous solutions for biological studies.

1981 ◽  
Vol 4 (4) ◽  
pp. 271-274
Author(s):  
P. K. Bassi ◽  
K. C. Eastwell ◽  
T. Akalehiywot ◽  
Mary S. Spencer
Keyword(s):  
Aqueous Solutions ◽  
Quantitative Determination ◽  
Biological Studies

scholarly journals Development and Validation of Method for the Quantitative Determination of Zinc in its Chelate Complexes Using Energy Dispersive X-ray Fluorescence Spectroscopy

2021 ◽  
Vol 10 (4) ◽  
pp. 154-161
Author(s):  
А. V. Marukhlenko ◽  
Т. V. Maksimova ◽  
Т. V. Pleteneva ◽  
М. A. Morozova
Keyword(s):  
Fluorescence Spectroscopy ◽  
Aqueous Solutions ◽  
Quantitative Determination ◽  
Zinc Sulfate ◽  
Zinc Content ◽  
Chelate Complex ◽  
Molar Ratio ◽  
X Ray ◽  
Validation Parameters

Introduction. The production, standardization and quality control process of various dietary supplements containing chelated zinc requires validated quantitative assessment methods. In this work, we propose an X-ray fluorescence spectroscopy (XRF) technique for determining the zinc content in the composition of coordination compounds using the example of a synthesized chelate complex with methionine.Aim. To synthesize Zn(Met)2 chelate complex, to develop and validate a method for its quantitative analysis using the XRF method.Materials and methods. The synthesized zinc chelate complex was investigated by IR spectroscopy. The XRF method was used to develop a method for quantifying the zinc content in the synthesized complex. We used dry mixtures of zinc sulfate monohydrate and L-methionine (Met) in a molar ratio of Zn to Met – 1 : 1, 1 : 2, 1 : 4, 1 : 8 and 1 : 16 and also aqueous solutions of zinc sulfate and L-methionine in a molar ratio of Zn to Met 1 : 2 with Zn concentrations from 0.5 to 100 mmol/l as calibration standards. Complexometric titration was used as an arbitration method for the quantitative determination of zinc content in the samples under study.Results and discussion. The IR spectrum of chelate complex confirmed the presence of a donor-acceptor bond between Zn2+ and the nitrogen atom of amino group in methionine. The titration results showed chelate compounds have a composition corresponding to the stoichiometric formula Zn(Met)2. XRF analysis of dry standard mixed samples demonstrated the presence of matrix effect, that makes impossible an accurate assessment of zinc content in the chelate compound. According to the XRF spectra of aqueous solutions containing zinc sulfate and methionine in a ratio of 1 : 2 at a zinc concentration of 0.5; 1; 2; 3; 4; 5; 10; 25; 50 and 100 mmol/L, a calibration graph was constructed – the dependence of the fluorescence signal intensity for the Kα line of zinc on the concentration of zinc in the solution (r = 0.9996). The method was evaluated by the following validation parameters: specificity, linearity, correctness, precision, and analytical range. The specificity of the validated method was proven in the presence of copper, iron, and silver.Conclusion. The developed method make it possible to determine with sufficient precision and correctness the content of Zn2+ in its aqueous solutions of inorganic and organic nature by the XRF method in the concentration range from 3 to 100 mmol/l without the influence of the matrix.

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