The Content Determination of Strongly Acidic Alkyl Phosphate with the Method of Potentiometric Titration

2011 ◽  
Vol 301-303 ◽  
pp. 241-244
Author(s):  
Qi Wang ◽  
Guo Zheng ◽  
Yu Sun ◽  
Xue Jing We ◽  
Jian Jie Ai
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Potentiometric Titration ◽  
Conventional Method ◽  
Phosphorus Oxychloride ◽  
Good Reproducibility ◽  
Content Determination ◽  
Alkyl Phosphate ◽  
Verification Test

The alkyl phosphate prepared by phosphorus oxychloride and fatty alcohol contained a large amount of hydrochloric acid but no chloride. So the content of phosphate mono- and diester couldn’t be determined by conventional method. In this paper the content of hydrochloric acid was determined by potentiometric titration at first, and then the conventional method can be used to detect the content of mono- and diester and phosphoric acid. In this way each component of the alkyl phosphate can be ascertained accurately. The method was verified simply and conveniently by verification test that could avoid extraction, recrystalli- zation and other cockamamie operation. It also had stronger application and good reproducibility.

Content Determination of Pb inOcher's Water Decoction and Vinegar Decoction

2011 ◽  
Vol 345 ◽  
pp. 270-275
Author(s):  
Lian Wei Kang ◽  
Nan Yan Xiong ◽  
Xiao Mei Wang
Keyword(s):  
Hydrochloric Acid ◽  
Clinical Application ◽  
Science Instruction ◽  
Potassium Fluoride ◽  
Content Determination ◽  
Vis Spectroscopy ◽  
Sample Decomposition

AIM: Establishment Pb the content determines separately method in ocher's Water decoction and the vinegar decoction. Provide the theory basis and the science instruction for the ocher clinical medication. MET Sample decomposition with hydrochloric acid and potassium fluoride. Determined the content of Pb in different characters mineral medicine haematitum by UV-vis spectroscopy, pH9~10, wavelength 520nm；Determined the content of Pb; .RESULTS It is different to the content of Pb in different characters mineral medicine haematitum. CONCLUSION：It should be differences in the clinical application.

Determination of Insoluble, Soluble, and Total Dietary Fiber in Foods and Food Products: Interlaboratory Study

1988 ◽  
Vol 71 (5) ◽  
pp. 1017-1023 ◽  
Author(s):  
Leon Prosky ◽  
Nils-Georg Asp ◽  
Thomas F Schweizer ◽  
Jonathan W Devries ◽  
Ivan Furda
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Dietary Fiber ◽  
Collaborative Study ◽  
Food Products ◽  
Separate Determination ◽  
Total Dietary Fiber ◽  
Insoluble Dietary Fiber ◽  
Soy Isolate

Abstract A collaborative study was conducted to determine the insoluble dietary fiber (IDF), soluble dietary fiber (SDF), and total dietary fiber (TDF) content of food and food products by using a combination of enzymatic and gravimetric procedures. The method was basically the same as that developed for TDF only, which was adopted official final action by AOAC, except for changing the concentration of buffer and base and substituting hydrochloric acid for phosphoric acid. These changes were made to improve the robustness of the method. Duplicate blind samples of soy isolate, white wheat flour, rye bread, potatoes, rice, corn bran, oats, Fabulous Fiber, wheat bran, and a high fiber cereal were analyzed by 13 collaborators. Dietary fiber values (IDF, SDF, and TDF) were calculated as the weight of residue minus the weight of protein and ash. The coefficients of variation (CVs) of both the independent TDF determination and the sum of IDF and SDF were better than 15 and 18%, respectively, with the exception of rice and soy isolate. These 2 foods, however, contained only about 1% TDF. The CVs of the IDF were equally good, except for Fabulous Fiber, for which filtration problems occurred. The CVs for the SDF were somewhat high, but these products had very low SDF content. There was excellent agreement between the TDF determined independently and the TDF determined by summing the IDF and SDF. The method for separate determination of IDF and SDF requires further study. The modifications (changes in concentration of buffer and base and the use of hydrochloric acid instead of phosphoric acid) to the official final action method for TDF have been adopted.

scholarly journals Determination of trace copper in water samples by flame atomic absorption spectrometry after preconcentration on a phosphoric acid functionalized cotton chelator

2008 ◽  
Vol 73 (2) ◽  
pp. 249-258 ◽  
Author(s):  
Renmin Gong ◽  
Demin Zhang ◽  
Keding Zhong ◽  
Min Feng ◽  
Xingyan Liu
Keyword(s):  
Hydrochloric Acid ◽  
Phosphoric Acid ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Water Samples ◽  
Solid Phase ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption

This paper reports the preparation of a phosphorylated cotton chelator (PCC) by solid phase esterification of phosphoric acid (PA) onto defatted cotton fibres using urea as the catalyst. The synthesized PCC was employed for the preconcentration of copper from water samples prior to its determination by flame atomic absorption spectrometry (FAAS). The preconcentration of copper was studied under both batch and column techniques. The pH range for the quantitative preconcentration of copper was 4.0-7.0. The sorption time required for each sample was less than 30 min by the batch method. The copper sorption capacity of the PCC was found to be 15.3 mg/g at the optimum pH value. Elution with 1.0 mol dm-3 hydrochloric acid was found to be quantitative. Feasible flow rates of the copper solution for quantitative sorption onto the column packed with PCC were 0.5-4.0 ml min-1, whereas the optimum flow rate of the hydrochloric acid solution for desorption was less than 1.5 ml min-1. An 80-fold preconcentration factor could be achieved under the optimum column conditions. The tolerance limits for common metal ions on the preconcentration of copper and the number of times of column reuse were investigated. The proposed method was successfully applied for the preconcentration and determination of trace copper in natural and drinking water samples by FAAS.

EINE CHEMISCHE METHODE ZUR BESTIMMUNG VON 16-EPI-ÖSTRIOL IM URIN DES MENSCHEN

1963 ◽  
Vol 44 (1) ◽  
pp. 47-66 ◽  
Author(s):  
W. Nocke ◽  
H. Breuer
Keyword(s):  
Melting Point ◽  
Phosphoric Acid ◽  
Aqueous Alkali ◽  
Percentage Error ◽  
Organic Layer ◽  
Maximum Percentage ◽  
Chemical Determination ◽  
Routine Assay ◽  
Hydrolysis Of

ABSTRACT A method for the chemical determination of 16-epi-oestriol in the urine of nonpregnant women with a qualitative sensitivity of less than 0.5 μg/24 h is described. The separation of 16-epi-oestriol and oestriol is accomplished by converting 16-epi-oestriol into its acetonide, a reaction which is stereoselective for cis-glycols and therefore not undergone by oestriol as a trans-glycol. Following partition between chloroform and aqueous alkali, the acetonide of 16-epi-oestriol is completely separated with the organic layer whereas oestriol as a strong phenol remains in the alkaline phase. 16-epi-oestriol is chromatographed on alumina as the acetonide and determined as a Kober chromogen. This procedure can easily be incorporated into the method of Brown et al. (1957 b) thus making possible the simultaneous routine assay of oestradiol-17β, oestrone, oestriol and 16-epi-oestriol from one sample of urine. The specificity of the method was established by separation of 16-epi-oestriol from nonpregnancy urine as the acetonide, hydrolysis of the acetonide by phosphoric acid, isolation of the free compound by microsublimation and identification by micro melting point, colour reactions and chromatography. The accuracy of the method is given by a mean recovery of 64% for pure crystalline 16-epi-oestriol when added to hydrolysed urine in 5–10 μg amounts. The precision is given by s = 0.24 μg/24 h. For the duplicate determination of 16-epi-oestriol the qualitative sensitivity is 0.44 μg/24 h, the maximum percentage error being ± 100% The quantitative sensitivity (±25% error) is 1.7 μg/24 h.

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