Determination Of Urea In Urine Research Articles

Evaluation of nitrate as internal standard for quantitative determination of urea in urine by Raman spectroscopy

Evaluation of nitrate as internal standard for quantitative determination of urea in urine by Raman spectroscopy

Spectrophotometric methods for the determination of urea in real samples using silver nanoparticles by standard addition and 2nd order derivative methods

In this work, we have developed simple, sensitive and inexpensive methods for the spectrophotometric determination of urea in urine samples using silver nanoparticles (AgNPs). The standard addition and 2nd order derivative methods were adopted for this purpose. AgNPs were prepared by chemical reduction of AgNO3 with hydrazine using 1,3-di-(1H-imidazol-1-yl)-2-propanol (DIPO) as a stabilizing agent in aqueous medium. The proposed methods were based on the complexation of AgNPs with urea. Using this concept, urea in the urine samples was successfully determined spectrophotometric methods. The results showed high percent recovery with ±RSD. The recoveries of urea in the three urine samples by spectrophotometric standard addition were 99.2%±5.37, 96.3%±4.49, 104.88%±4.99 and that of spectrophotometric 2nd order derivative method were 115.3%±5.2, 103.4%±2.6, 105.93%±0.76. The results show that these methods can open doors for a potential role of AgNPs in the clinical determination of urea in urine, blood, biological, non-biological fluids.

Strip bioelectrochemical cell for potentiometric measurements fabricated by screen-printing

Miniaturized, planar bioelectrochemical cell dedicated for potentiometric detection of urea manufactured in integrated strip format has been developed. The enzyme electrode and the reference electrode, both based on ruthenium dioxide were fabricated only by means of screen-printing. The application of the thick-film technology results in highly reproducible and cost-effective manufacturing procedure, easily adapted to large-scale production. The developed system of planar electrodes can be applied as a disposable device for drop-on measurements as well as a detector for a multiple use in flow injection analysis. The biosensor is useful for determination of urea in millimolar range of concentrations. The developed strip biosensor is also useful as a disposable device for potentiometric detection of heavy metal ions, which are able to inhibit urease. The utility of the developed devices for determination of urea in urine and serum samples is demonstrated.

Determination of urea in urine using a conductivity cell with surface acoustic wave resonator-based measurement circuit

A conductivity cell employing a 61 MHz surface acoustic wave resonator-based measurement circuit was applied to the detection of the urea/urease reaction. The kinetic enzymatic parameters of the urease were estimated from the frequency shifts. The effects of pH, temperature and inhibitor on the response of the enzyme conductivity measurement system were investigated. The system was applied to rapid determination of urea in small urine samples. The lowest detection limit of urea was 30 ng/ml.

Characterization of biosensors based on membranes containing a conducting polymer

A new type of biosensor based on the coupling of an enzyme to an ion-selective membrane containing a conducting polymer is evaluated. The results obtained with the enzyme field- effect transistor (ENFET) and the ion-selective electrode (ISE) for the determination of creatinine and urea are compared. The presence of the conducting polymer significantly lowers the detection limit for creatinine by one decade to 10 −7 and 10 −4 M for the ENFET and ISE, respectively. The determination of urea in urine and serum with the ENFET was carried out, and the results correlated well with those obtained by spectrophotometry.

Rapid analysis of urea in urine by gas permeation-gas chromatography

An apparatus for rapid determination of urea in urine was developed by combining a system for the chemical decomposition of urea with the apparatus previously developed by the present authors for blood gas analysis. In this method, urea injected into the stream of sodium nitrite-nitric acid solution was decomposed to nitrogen and carbon dioxide. Evolved gases were separated from the solution by permeating them through a silicone tube and introduced to the gas chromatograph with the carrier gas. Amount of urea was determined from peak areas of nitrogen and/or carbon dioxide in the chromatogram. When 100 μl of urine was injected, urea was determined within 7 min with coefficient of variation in less than 2 %. The precision of the present method was comparable to that by urease-indophenol method which has been conventionally used for urea determination. The correlation between the both methods was good.

Direct Fluorometric Determination of Urea in Urine

Abstract In this quantitative fluorometric method, diacetylmonoxime is used for the determination of the urea. The products of the reaction of urea with diacetylmonoxime in acid solution exhibit two fluorescence maxima, at 410 and 525 nm. The intensity of the 525 nm maximum is linear over a wide range of urea concentration and the reaction is shown to be practically specific for urinary urea.

An improved technique for the analysis of amino acids and related compounds on thin layers of cellulose : VII. A simple technique for the estimation of blood urea and of its clearance from plasma

A simple method is described for the rapid determination of blood urea which can be applied to the estimation of renal function. When combined with the concurrent determination of urea in urine, accurate urea clearance values are obtained.

A colorimetric method for the direct determination of urea in urine

A colorimetric method for the direct determination of urea in urine

A method for the direct determination of urea in urine

A method for the direct determination of urea in urine

UREA RETENTION

Simple clinical methods that furnish accurate data are desirable in the study of renal function, particularly for the physician to whom the complicated methods of analyzing the blood are not available. The method reported in this article is of interest as an accurate index to the urea of the blood. The standard determination of blood urea by the urease method is an admirable test but requires very careful technic, certain laboratory facilities and is somewhat time consuming. The method herein reported requires only elementary laboratory knowledge and very simple equipment; only about fifteen minutes are required, and it gives adequate clinical results. It is the estimation of the mercury combining power of deproteinized blood. NOTES ON THE LITERATURE Liebig1in 1853 made use of the ability of mercury to combine with nitrogenous products in a method for the determination of urea in urine. In 1921 Friedlander2reported a titrametric method