Comparison of Carbonate and Uricase-Carbonate Methods for the Determination of Uric Acid in Serum

1966 ◽  
Vol 12 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Wendell T Caraway ◽  
Herman Marable

Abstract A colorimetric carbonate procedure for the determination of uric acid has been modified to include incubation of serum with uricase to destroy uric acid. Residual nonurate chromogens are subtracted from total chromogens to obtain the concentration of "true" uric acid. Result obtained by the carbonate and the uricase-carbonate methods were in good agreement. The mean concentration of nonurate chromogens in serum is approximately 2% of the true uric acid values. Recovery of uric acid added to serum is essentially quantitative. Formaldehyde markedly inhibits uricase activity and interferes with recoveries. The uricase-carbonate method is applicable to hemolytic serum and to serums from patients with uremia or those receiving high doses of salicylate in which excess concentrations of nonurate chromogens may be encountered.

1972 ◽  
Vol 1 (13) ◽  
pp. 55
Author(s):  
J. Kirkegarrd Jensen ◽  
Torben Sorenson

The paper describes a procedure for obtaining field data on the mean concentration of sediments in combination of waves and currents outside the breaker zone, as well as some results of such measurements. It is assumed that the current turbulence alone is responsible for the maintenance of the concentration profile above a thin layer close to the bottom, in which pick-up of sediments due to wave agitation takes place. This assumption gives a good agreement between field data and calculated concentration profiles.


1966 ◽  
Vol 12 (11) ◽  
pp. 748-766 ◽  
Author(s):  
Stanley Morgenstern ◽  
Richard V Flor ◽  
James H Kaufman ◽  
Bernard Klein

Abstract An automated procedure is presented for the enzymatic determination of serum uric acid on both the AutoAnalyzer and the Robot Chemist. The procedure measures as the neocuproine complex, the difference in the amount of Cu+ formed by reaction of a Cu++-alkanolamine buffered solution with serum uric acid under precisely controlled conditions before and after uricase treatment of the serum. The difference is proportional to the true serum uric acid content. The elements contributing to the enzymatic reaction, the colorimetric reaction, and the elimination of interferences were investigated. Comparison of serum uric acid values obtained by this method with those obtained by ultraviolet spectrophotometry show very good agreement.


1993 ◽  
Vol 71 (5) ◽  
pp. 769-770
Author(s):  
K. Soliman ◽  
L. Zikovsky ◽  
C. Dallaire

The concentration of Al, P, and Si in 142 samples of five fruit juices, measured with neutron activation analysis and atomic absorption spectroscopy, varies from 0 to 1.44, 31 to 201, and 1.5 to 35 µg/mL, respectively. The mean concentration of Al in apple, grape, grapefruit, orange, and pineapple juices is 0.54, 0.94, 0.24, 0.29, and 0.62 µg/mL, respectively. The mean concentration of P in the same juices is 102, 115, 124, 127, and 76 µg/mL. The storage of juice in aluminized containers with internal plastic coating does not increase the concentration of Al in the juice.


1963 ◽  
Vol 26 (1) ◽  
pp. 65-73 ◽  
Author(s):  
M. G. BRUSH

SUMMARY Plasma levels of progesterone and 20 α-hydroxypregn-4-en-3-one have been studied after intravenous (i.v.) and intramuscular (i.m.) injections of progesterone in sheep. I.v. injected progesterone was removed from the bloodstream very rapidly and it was necessary to give 50 mg. before it was possible to detect progesterone at times up to 10 min. after the injection. With 100 mg. amounts of progesterone injected i.v. the mean concentration in samples taken up to 10 min. after the injection was 34·7 μg./100 ml. plasma (range 4–110 μg./100 ml. in 9 samples), but after 1 hr. the mean level was 2·2 μg./100 ml. plasma (range 0–10 μg./100 ml. in 10 samples). The concentrations of 20 α-hydroxypregn-4-en-3-one were usually, but not always, less than those of progesterone. When progesterone was given by i.m. injection it was not possible to establish detectable blood levels. The effect of the injection vehicle was also studied for each injection route. Some new modifications of Short's method (1958) for the determination of plasma progesterone are described and discussed.


Author(s):  
Tomomi Uchiyama ◽  
Akihito Ichikawa

The diffusion of matter in compound round jet is simulated by three-dimensional particle method. The flow field is calculated with a vortex method, whereas the concentration field is simulated through a particle method analogous to the vortex method. It is shown that the concentration distribution yielded by the three-dimensional vortical flow is in good agreement with the experimental one obtained by the flow visualization. The mean concentration is confirmed to be in the self-preservation state.


2008 ◽  
Vol 91 (3) ◽  
pp. 542-550 ◽  
Author(s):  
Nahed El-Enany

Abstract A rapid, simple, and highly sensitive second derivative synchronous fluorometric method has been developed for the simultaneous determination of metoclopramide (MT) and pyridoxine (PY) in a binary mixture. The method is based on measurement of the native fluorescence of these drugs at = 80 nm in methanol. The different experimental parameters affecting the native fluorescence of the drugs were carefully studied and optimized. The fluorescence-concentration plots were rectilinear over the ranges of 0.020.4 and 0.12 g/mL for MT and PY, respectively. The limits of detection were 0.003 and 0.007 g/mL and the limits of quantification were 0.008 and 0.02 g/mL for MT and PY, respectively. The proposed method was successfully applied to the determination of MT and PY in synthetic mixtures and in commercial syrup. The results were in good agreement with those obtained with a reported method. The high sensitivity attained by the proposed method allowed the determination of MT in spiked and real human plasma samples. The mean percent recoveries of MT from spiked and real human plasma (n = 3) were 93.72 3.15 and 89.72 2.19, respectively.


2012 ◽  
Vol 32 (2) ◽  
pp. 401-404 ◽  
Author(s):  
Cristiano Augusto Ballus ◽  
Adriana Dillenburg Meinhart ◽  
Carolina Schaper Bizzotto ◽  
José Teixeira Filho ◽  
Helena Teixeira Godoy

Energy drinks are becoming popular in Brazil and in the world due to their stimulant properties. Caffeine is present in energy drinks with the aim of stimulating the central nervous system and intensifying brain activity. On the other hand, the ingestion of high doses of caffeine can cause undesirable symptoms such as anxiety and tachycardia. Therefore, it is necessary to monitor the caffeine content added to energy drinks to guarantee that the levels in the final product are in accordance with the labeling and within the legislation limits. The goal of this work was to validate a fast, efficient, and low-cost method for the determination of caffeine in energy drinks by micellar electrokinetic chromatography (MEKC). A total of seven brands were analyzed, each in three lots. The electrolyte was prepared with 50 mmol.L-1 of sodium dodecyl sulfate (SDS) and 10 mmol.L-1 of sodium carbonate (pH 11.0). The mean concentration of caffeine ranged from 122.8 to 318.6 mg.L-1. None of the brands had caffeine levels above the maximum limit. Considering the interval of confidence (95%), 72% of the samples had less caffeine than the amount informed on the product label.


1999 ◽  
Vol 117 (3) ◽  
pp. 108-112 ◽  
Author(s):  
Jacob Rosenblit ◽  
Cláudia Regina Abreu ◽  
Leonel Nulman Szterling ◽  
José Mauro Kutner ◽  
Nelson Hamerschlak ◽  
...  

CONTEXT: The hemoglobin (Hb) level is the most-used parameter for screening blood donors for the presence of anemia, one of the most-used methods for measuring Hb levels is based on photometric detection of cyanmetahemoglobin, as an alternative to this technology, HemoCue has developed a photometric method based on the determination of azide metahemoglobin. OBJECTIVE: To evaluate the performance of three methods for hemoglobin (Hb) determination in a blood bank setting. DESIGN: Prospective study utilizing blood samples to compare methods for Hb determination. SETTING: Hemotherapy Service of the Hospital Israelita Albert Einstein, a private institution in the tertiary health care system. SAMPLE: Serial blood samples were collected from 259 individuals during the period from March to June 1996. MAIN MEASUREMENTS: Test performances and their comparisons were assessed by the analysis of coefficients of variation (CV), linear regression and mean differences. RESULTS: The CV for the three methods were: Coulter 0.68%, Cobas 0.82% and HemoCue 0.69%. There was no difference between the mean Hb determination for the three methods (p>0.05). The Coulter and Cobas methods showed the best agreement and the HemoCue method gave a lower Hb determination when compared to both the Coulter and Cobas methods. However, pairs of methods involving the HemoCue seem to have narrower limits of agreement (± 0.78 and ± 1.02) than the Coulter and Cobas combination (± 1.13). CONCLUSION: The three methods provide good agreement for hemoglobin determination.


1967 ◽  
Vol 50 (3) ◽  
pp. 680-682
Author(s):  
Laura A Roberts

Abstract Eight collaborators studied a fluoromelric and thin layer chromatographic method for aminacrine and its salts in powder and cream drug preparations. Recovery of aminacrine.HCI by fluorometer in both preparations averaged 100% for powder and 102% for cream. The mean concentration of aminacrine.HCI found in the powder was 0.108% with a standard deviation of ± 0.001%. The mean concentration of aminacrine found in the cream was 0.191% with a standard deviation of ± 0.003%. Seven of the 8 collaborators successfully used thin layer chromatography to identify the aminacrine in both sample forms supplied. The assay method for aminacrine and its salts in drug preparations is recommended for adoption as official, first action


1967 ◽  
Vol 50 (4) ◽  
pp. 776-781
Author(s):  
N P Sen

Abstract A collaborative study of an enzymaticultraviolet method for determining uric acid in flour was made by 10 laboratories on 3 flour samples containing varied proportions of infested flour and one sample containing a known amount of added uric acid. The mean recovery of the added uric acid (16.91 mg/100 g) was 103%. The precision and accuracy of the collaborative results were within reasonable range for an enzymatic method.


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