Milk. Determination of lactose content. Enzymatic method using difference in pH

2010 ◽  
Keyword(s):  
Enzymatic Method

Optimization of an enzymatic method for the determination of lysosomal N-acetyl-β-D-hexosaminidase and β-glucuronidase in synovial fluid

2006 ◽  
Vol 44 (8) ◽  
Author(s):  
Justyna Marciniak ◽  
Anna Zalewska ◽  
Janusz Popko ◽  
Krzysztof Zwierz
Keyword(s):  
Synovial Fluid ◽  
Enzymatic Method

AbstractClin Chem Lab Med 2006;44:933–7.

scholarly journals Determination of uric acid in human serum by an enzymatic method using N-methyl-N-(4-aminophenyl)-3-methoxyaniline reagent

2003 ◽  
Vol 68 (8-9) ◽  
pp. 691-698 ◽  
Author(s):  
Milena Jelikic-Stankov ◽  
Predrag Djurdjevic ◽  
Dejan Stankov
Keyword(s):  
Uric Acid ◽  
Human Serum ◽  
Limit Of Detection ◽  
Ascorbate Oxidase ◽  
Acid Oxidation ◽  
Uric Acid Concentration ◽  
Enzymatic Method ◽  
Limit Of Quantification ◽  
Relative Standard

In this work a new enzymatic method for the determination of uric acid in human serum has been developed. The method is based on the oxidative coupling reaction between the N-methyl-N-(4-aminophenyl)-3-methoxyaniline (NCP) reagent and the hydrogen ? donor reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline (TOOS), in the system involving three enzymes: uricase, peroxidase and ascorbate oxidase. Using this method uric acid could be determined in concentrations up to 1.428 mmol/L, with a relative standard deviation of up to 1.8 %. The effect of the medium pH and the NCP concentration on the linearity of the chromogen absorbance versus the uric acid concentration curve was investigated. The influence of the uricase activity on the maximum rate of uric acid oxidation was also examined. The use of the NCP reagent demonstrated a more precise and more sensitive determination of the uric acid compared to the determination with 4-aminoantipyrine (4-AA) as the coupling regent. The sensitivity of the method determined from the calibration curve was 0.71 absorbance units per mmol/L of uric acid; the limit of detection was LOD = 0.0035 mmol/L and the limit of quantification was LOQ = 0.015 mmol/L of uric acid.

Kinetic Enzymatic Method for Determining Serum Creatinine

1975 ◽  
Vol 21 (10) ◽  
pp. 1422-1426 ◽  
Author(s):  
Gerald A Moss ◽  
Richard J L Bondar ◽  
Diane M Buzzelli
Keyword(s):  
Serum Creatinine ◽  
Accurate Determination ◽  
Test Subject ◽  
Rate Of Change ◽  
Enzymatic Method ◽  
Inhibitory Effects ◽  
Standard Curve ◽  
Analytical Recovery ◽  
Enzymatic Procedure

Abstract Creatinine amidohydrolase is used to measure serum creatinine in a totally enzymatic procedure. Creatine, produced by hydrolysis, is acted upon by creatine kinase, and then by pyruvate kinase and lactate dehydrogenase, to result in a change in absorbance at 340 nm. The amount of creatinine present is related to the rate of change in A340 and is determined from a standard curve. Absorbance and concentration are linearly related to 100 mg/liter and only 250 µl of serum is required. At 1.0 g/liter, heparin, oxalate, citrate, ethylenediaminetetraacetate, ascorbate, or glucose had no significant effect on the accurate determination of creatinine; higher concentrations (30 g/liter) had inhibitory effects on the test. Analytical recovery of creatinine added to either normal or abnormal sera averaged 102%. When results of this procedure and of the standard direct Jaffé test were compared, the latter were significantly higher. Unlike the Jaffé method, the present method of determining creatinine is rapid (about 10 min per test), subject to few or no interfering substances, and requires no serum deproteinization.

Enzymatic Method for Determination of Inorganic Phosphate in Serum and Urine with a Centrifugal Analyzer

1974 ◽  
Vol 20 (3) ◽  
pp. 332-336 ◽  
Author(s):  
Michael A Pesce ◽  
Selma H Bodourian ◽  
John F Nicholson
Keyword(s):  
Inorganic Phosphate ◽  
Enzymatic Method ◽  
Molybdenum Blue ◽  
Enzyme Substrate ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Method Show ◽  
Serum And Urine

Abstract We describe an enzymatic method for determining inorganic phosphate in serum and urine, with use of the "CentrifiChem." The sample is mixed with a combined enzyme—substrate system consisting of the enzymes phosphorylase a, phosphoglucomutase, and glucose-6-phosphate dehydrogenase, the coenzyme NADP, the substrate glycogen, and adenosine 5'-monophosphate as the activator for phosphorylase. The increase in absorbance at 340 nm as NADPH is formed is linearly proportional to the concentration of inorganic phosphate to 15 mg P/dl. This method circumvents deproteinization and requires only 10 µl of sample. Results obtained with the automated enzymatic method show good correlation with manual and automated molybdenum blue methods.

Sign in / Sign up

Export Citation Format

Share Document