Quantitative Analysis by an Automatic Potentiometric Reaction Rate Method. Specific Enzymatic Determination of Glucose

1961 ◽  
Vol 33 (8) ◽  
pp. 1040-1047 ◽  
Author(s):  
H. V. Malmstadt ◽  
H. L. Pardue
Keyword(s):  
Quantitative Analysis ◽  
Reaction Rate ◽  
Enzymatic Determination ◽  
Rate Method

Automated Enzymatic Determination of L-Lactate in Serum, with Use of a Miniature Centrifugal Anlyzer

1976 ◽  
Vol 22 (12) ◽  
pp. 2038-2041 ◽  
Author(s):  
T P Hadjiioannou ◽  
S I Hadjiioannou ◽  
S D Brunk ◽  
H V Malmstadt
Keyword(s):  
Lactate Dehydrogenase ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Reaction Rates ◽  
Enzymatic Determination ◽  
Analytical Recovery ◽  
Rate Method ◽  
Relative Errors ◽  
Lithium Lactate

Abstract We describe an automated enzymatic reaction-rate method for spectrophotometric determination of lactate in serum with a miniature centrifugal analyzer. The L(+)-lactate is selectively oxidized in the presence of lactate dehydrogenase (EC 1.1.1.27) and NAD+ to from NADH, whitch is measured from its absorption. Reaction rates are determined automatically, and unknown concentrations are calculated from a computer0generated calibration curve with aqueous lithium lactate standards. Lactte concentrations in the range 0.32-1.6 µg/4 µl (80-400 mg/liter) of sample were determined with relative errors and coefficient of variation of 4.8%. Analytical recovery of lactate added to pooled serum was 89-112% (average, 101%). Comparison with a kit ("Rapid Lactate") method gave a correlation coefficient squared of 0.979 over a concentration range of 39-779 mg/liter.

Specific Enzymatic Determination of Glucose in Blood Serum or Plasma by an Automatic Potentiometric Reaction-Rate Method

1962 ◽  
Vol 8 (6) ◽  
pp. 606-615 ◽  
Author(s):  
H V Malmstadt ◽  
H L Pardue
Keyword(s):  
Blood Serum ◽  
Blood Plasma ◽  
Reaction Rate ◽  
Measurement Time ◽  
Sample Handling ◽  
Enzymatic Determination ◽  
Speed Up ◽  
Rate Method ◽  
Relative Errors

Abstract A new automatic potentiometric reaction-rate method has been applied to the specific enzymatic measurement of glucose in blood plasma or serum. A new filtering technic is described for removal of precipitated protein. The use of injection pipets to simplify and speed up the reagent-and sample-handling step is described. Glucose is determined in 0.02 ml. of serum or plasma with relative errors within 2%. The average measurement time is about 30 sec.

Automated enzymatic determination of L-lactate in serum, with use of a miniature centrifugal analyzer.

1976 ◽  
Vol 22 (12) ◽  
pp. 2042-2045 ◽  
Author(s):  
T P Hadjiioannou ◽  
S I Hadjiioannou ◽  
S D Brunk ◽  
H V Malmstadt
Keyword(s):  
Lactate Dehydrogenase ◽  
Reaction Rate ◽  
Enzymatic Reaction ◽  
Reaction Rates ◽  
Enzymatic Determination ◽  
Analytical Recovery ◽  
Rate Method ◽  
Relative Errors ◽  
Lithium Lactate

Abstract We describe an automated enzymatic reaction-rate method for spectrophotometric determination of lactate in serum with a miniature centrifugal analyzer. The L(+) -lactate is selectively oxidized in the presence of lactate dehydrogenase (EC 1.1.1.27) and NAD+ to form NADH, which is measured from its absorption. Reaction rates are determined automatically, and unknown concentrations are calculated from a computer-generated calibration curve with aqueous lithium lactate standards. Lactate concentrations in the range 0.32-1.6 mug/4 mul (80-400 mg/liter) of sample were determined with relative errors and coefficient of variation of 4.8%. Analytical recovery of lactate added to pooled serum was 89-112% (average, 101%). Comparison with a kit ("Rapid Lactate") method gave a correlation coefficient squared of 0.979 over a concentration range of 39-779 mg/liter.

Reaction-rate method for the determination of phosphorus in agricultural products

Talanta ◽  
1979 ◽  
Vol 26 (6) ◽  
pp. 467-471 ◽  
Author(s):  
M.S. McCracken ◽  
H.V. Malmstadt®
Keyword(s):  
Reaction Rate ◽  
Agricultural Products ◽  
Rate Method

Enzyme-catalyzed reaction-rate method for determination of arsenic in water

1978 ◽  
Vol 50 (12) ◽  
pp. 1608-1611 ◽  
Author(s):  
Scott R. Goode ◽  
Ray J. Matthews
Keyword(s):  
Reaction Rate ◽  
Rate Method

Reaction-Rate Method for Determining Protein Nitrogen in Grains and Feeds

1979 ◽  
Vol 62 (1) ◽  
pp. 23-28
Author(s):  
Michael S Mccracken ◽  
Howard V Malmstadt
Keyword(s):  
Quantitative Determination ◽  
Reaction Rate ◽  
Mixed Solution ◽  
Protein Nitrogen ◽  
Digestion Procedure ◽  
Relative Standard ◽  
Aoac Method ◽  
Rate Method ◽  
Feed Samples

Abstract In a new automated reaction-rate method for the quantitative determination of protein nitrogen in grains and feeds, the ammonia-sodium phenate-hypochlorite reaction is used for the reaction-rate determination. After samples are digested by the official AOAC block digestion procedure, automated instrumentation is used to precisely and rapidly combine the reactants and transfer the mixed solution to an automated spectrophotometer. The rate of formation of the indophenol during 15 sec at 635 nm is automatically determined and compared with rates obtained for nitrogen standards to determine the protein nitrogen content in the sample. Relative standard deviations of about 0.6% are obtained. Results for grain and feed samples are comparable to those obtained by the official AOAC method.

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