scholarly journals IODIMETRY-PHOTOMETRIC DETERMINATION OF PERIODATE, IODATE AND BROMATE IN WATER SOLUTIONS

Author(s):  
O. Тrohimenko ◽  
O. Zaporozhets ◽  
A. Тrohimenko

A simple and accurate three-step procedure for sequential spectrophotometric determinations of periodate, iodate and bromate in aqueous media has been developed. At the first stage the determination of periodate is based on the selective oxidation of the excess amount of iodide at pH=4.8 to produce iodine (triiodide), that can be found by spectrophotometric detection (λmax=350 nm). After detecting the analytical signal, iodine is removed from the solution by sorption on the polyurethane foam. In the second stage the determination of iodate is based on the selective oxidation of iodide at pH=3.0 to produce iodine (triiodide), that also can be found by spectrophotometric detection (λmax=350 nm). After detecting the analytical signal, also iodine is removed from the solution by sorption on the polyurethane foam. In the third stage the determination of bromate is based on the selective oxidation of iodide at pH=1.0 to produce iodine (triiodide), that also can be found by spectrophotometric detection (λmax=350 nm). It has been established that the equilibrium in the reaction (ІО4– + 7І– + 8Н+ → 4І2 +4Н2О) is established in 3 minutes at pH=4.8. The equilibrium in the both reactions (ІО3– + 5І– + 6Н+ → 3І2 +3Н2О and BrО3– + 6І– + 6Н+ → 3І2 +Br– +3Н2О) is established in 7 minutes at pH=3.0 and at pH=1.0 respectively. It was found that oxohalogates are quantitatively converted to I2 with ~ 100-fold molar excess iodide at appropriate optimal pH values. Schematically, the determination of IO4–, IO3– and BrO3– in their combined presence can be represented as follows: where SF is spectrophotometry in a solution at 350 nm: PUF is the polyurethane foam. Based on the data obtained, the model mixtures of periodate, iodate and bromate by sequential iodiometry-photometric method were analyzed. The error of determination in mixtures of each oxo-halogenate did not exceed 5%.

1965 ◽  
Vol 48 (6) ◽  
pp. 1095-1100
Author(s):  
James P Ussary ◽  
Charles W Gehrke

Abstract Three primary standard grade potassium salts, eight Magruder check samples, and 18 commercial fertilizer samples were analyzed by three methods. Primary standards gave an average recovery of 100.0% and an average range of 0.21% K20. Magruder check samples averaged 0.09% K20 higher by the modified flame photometric method than the grand averages of the STPB results on the respective Magruder reports. The modified flame photometric method averaged 0.02% K20 lower than the official flame photometric method and 0.11% K20 higher than the official STPB method on 18 commercial fertilizer samples. The automatic flame photometric method, without anion exchange cleanup, is rapid enough for routine analysis and is as accurate and precise as the AOAC official methods. The method was also applied to the direct available P205 extract. Results on three primary grade potassium salts, seven Magruder check samples, and 13 commercial fertilizer samples were as accurate and precise as the official STPB method.


2006 ◽  
Vol 61 (1) ◽  
pp. 25-27 ◽  
Author(s):  
L. N. Moskvin ◽  
A. V. Bulatov ◽  
E. A. Rudenko ◽  
D. V. Navolotskii ◽  
G. I. Koldobskii

1991 ◽  
Vol 65 (05) ◽  
pp. 535-540 ◽  
Author(s):  
Karl Fickenscher ◽  
Angela Aab ◽  
Werner Stüber

SummaryAn assay for a direct photometric determination of F XIII in untreated and undiluted plasma was developed. In a one-step procedure F XIII is activated by thrombin and Ca2+ and crosslinks glycine-ethylester to a specific glutamine containing peptide substrate. The released ammonia is incorporated into α-keto-glutarate by glutamate dehydrogenase, and the NADH consumption of this reaction is measured photometrically at 340 nm. NADH-consumption is directly proportional to the F XIII activity. Fibrin polymerization and the corresponding turbidity is avoided by the use of a fibrin aggregation inhibitor.The procedure is rapid and simple and enables to measure within the range of 0 to 150% F XIII. It can be performed with automated analyzers as well as with common photometric equipment.The normal range of F XIII activity in 167 healthy donors was determined to be 70 to 140%.


1984 ◽  
Vol 67 (4) ◽  
pp. 847-850
Author(s):  
Layna D Steele ◽  
Kelly J Ramsey ◽  
Peter F Kane

Abstract Current automated instrument systems used in conjunction with the official AOAC flame photometric method for K2O in fertilizer, 2.D06, all require a dilution step to bring the fertilizer extract to the appropriate concentration range. Two CFA (Continuous Flow Analysis) automated instrument systems are described which together eliminate aliquoting over the full range of fertilizer potassium, a significant saving of analyst effort if large numbers of samples are analyzed. The systems have performance characteristics well within the limits in the official method, and produce results comparable to current methods on routine samples.


Author(s):  
V. A. Makarov ◽  
T. K. Savosteenko

The requirements for the content of hexavalent chromium in cements and raw materials for its manufacture are described. The problem with the utilization of dust from gas treatment plants of metallurgical plants at metallurgical enterprises is given. The influence of the chemical composition of the dust of gas cleaning plants of metallurgical plants on the determination of hexavalent chromium is established. A method for measuring the hexavalent chromium in the dust of gas cleaning plants of metallurgical plants by the photometric method is described. A method has been developed for extracting hexavalent chromium from dust at the cleaning units of metallurgical plants for subsequent photometric determination. An extraction method has been established to prevent underestimation of the hexavalent chromium content. The determination of hexavalent chromium was based on the formation of a blue-violet complex with diphenylcarbazide. Calibration was carried out on aque solutions with a known concentration of hexavalent chromium. For the preparation of calibration solutions, potassium dichromate of chemical purity was used. The concentration of hexavalent chromium in each calibration solution was carried out by a calculation method, overlapping the entire measurement range. The measurement of optical density was carried out on a photoelectric colorimeter type KFK-3, at a wavelength of 540 nm. Analysis of the obtained calibration dependence showed a good correlation. The calibration factor was calculated using the least square method. Extraction of hexavalent chromium from the sample to be analyzed was performed with water. The reducing effect of iron was eliminated with a solution of phosphoric acid. The developed technique is used when conducting certification control of dust from gas cleaning units of metallurgical plants, as well as during research.A validation procedure was carried out. Obtained acceptable limits of repeatability and reproducibility of the method.


2009 ◽  
Vol 7 (3) ◽  
pp. 576-585 ◽  
Author(s):  
N. Burham ◽  
S.M. Abdel-Azeem ◽  
M.F. El-Shahat

AbstractIn the present paper, an off-line preconcentration procedure for the determination of cadmium and lead by flame atomic absorption spectrometry (FAAS) is proposed. Polyurethane foam (PUF) functionalized with o-aminophenol (o-AP) followed by Pyrazolone (Pyr) packed in a minicolumn was used as a sorbent material. The metals were retained on the modified PUF, from which it could be eluted and effectively preconcentrated. The detection limits were 0.072 and 0.016 μg L−1 for Pb and Cd respectively. Enrichment factors were 250 and 319 for lead and cadmium respectively. The procedure has been applied successfully to metal determination in water samples, fish liver and reference material.


1998 ◽  
Vol 373 (2-3) ◽  
pp. 131-138 ◽  
Author(s):  
S.G. Dmitrienko ◽  
L.V. Goncharova ◽  
A.V. Zhigulev ◽  
R.E. Nosov ◽  
N.M. Kuz̀min ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document