scholarly journals Application of an improved biuret method to the determination of total protein in urine and cerebrospinal fluid without concentration step by use of Hitachi 7170 auto-analyzer

2001 ◽  
Vol 15 (4) ◽  
pp. 161-164 ◽  
Author(s):  
Xu Guobing ◽  
Jiao Lili ◽  
Zhu Lihua ◽  
Xia Tiean
1983 ◽  
Vol 29 (1) ◽  
pp. 126-129 ◽  
Author(s):  
P R Finley ◽  
R J Williams

Abstract We evaluated a rate colorimetric method (Beckman) for measuring total protein in cerebrospinal fluid. The automated instrument we used was Beckman's ASTRA TM. A 100-microL sample of spinal fluid is introduced into the biuret reagent in the reaction cell and the increase in absorbance at 545 nm is monitored for 20.5 s. Solid-state circuits determine the rate of alkaline biuret-protein chelate formation, which is directly proportional to the total protein concentration in the sample. The linear range of measurement is 120 to 7500 mg/L. Day-to-day precision (CV) over the range of 150 to 1200 mg/L ranged from 15.2 to 2.3%. The method was unaffected by radical alteration of the albumin/globulin ratio, but there is a positive interference in the presence of hemoglobin, a suppression in the presence of bilirubin, and no effect by xanthochromia. The method is precise, accurate, rapid, and convenient. The method was compared with the trichloroacetic acid method as performed on the Du Pont aca III, giving a correlation coefficient (r2) of 0.9693. The method is precise, accurate, rapid, and convenient.


2020 ◽  
Vol 187 (8) ◽  
pp. e62-e62
Author(s):  
Pablo Jimenez Rihuete ◽  
Nicolas Villarino ◽  
Alicja Pelisiak ◽  
Luis M Rubio-Martinez

BackgroundRefractometric determination of total protein (TP) in synovial fluid (SF) is commonly used for diagnosis and monitoring of synovial sepsis in horses. Previous studies have shown that elevated concentrations of certain anticoagulants may overestimate refractometric determination of TP concentration.ObjectivesThe aim of the study was to evaluate the effect of different concentrations of dipotassium EDTA (K2EDTA) and lithium heparin (LH) on TP determination by using a hand-held refractometer in equine synovial fluid.Study designCross-section observational study.MethodsThirty samples of synovial fluid obtained from 22 horses with different synovial conditions were collected. Synovial fluid samples were separated into different aliquots and placed in commercially available collection tubes containing K2EDTA or LH at four different concentrations (1.76, 3.52, 7.04 and 17.6 mg/ml for K2EDTA; 16, 32, 64 and 160 IU/ml for LH) . Refractometric TP determination was performed on untreated and K2EDTA and LH aliquots with a hand-held refractometer and by spectophotometric Biuret method as the gold standard.ResultsRefractometric TP determination was overestimated in SF samples containing 10 times the recommended K2EDTA concentrations. Lower concentrations of K2EDTA and LH concentrations did not affect refractometric TP determinations.Main limitationsLimited number of samples mostly obtained from large synovial structures.ConclusionTo avoid incorrect TP determination, the use of LH containing collection tubes may be an appropriate alternative when the SF volume available is not enough to fill the K2EDTA collection tube.


Talanta ◽  
2014 ◽  
Vol 128 ◽  
pp. 38-43 ◽  
Author(s):  
Kamil Strzelak ◽  
Agnieszka Wiśniewska ◽  
Dagna Bobilewicz ◽  
Robert Koncki

1980 ◽  
Vol 26 (10) ◽  
pp. 1454-1458 ◽  
Author(s):  
C E Shideler ◽  
K K Stewart ◽  
J Crump ◽  
M R Wills ◽  
J Savory ◽  
...  

Abstract We have examined the feasibility of the automated multiple flow-injection technique for application to clinical chemistry by adapting to this system the biuret method for the determination of total protein. Samples were discretely and rapidly introduced into a continuously flowing, nonsegmented reagent stream by means of an automatic sampler and high-pressure injection valve. Pumps operating at 1380-2070 kPa (200-300 psi) were utilized to introduce the biuret reagent and saline diluent into the system separately at flow rates of 72 and 47 microL/s, respectively. Use of 20-microL sample and a 3.0-s reaction-delay coil was adequately sensitive for analysis for total protein by this method. Samples were analyzed at a rate of 150/h with no detectable between-sample carryover. Within-run precision studies yielded relative standard deviations of 2.5% and less. Total protein values obtained by this method correlated well with those obtained by centrifugal analyzer and bubble-segmented continuous-flow biuret methods.


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