Stopped-flow determination of paracetamol and oxyphenbutazone alone and in mixtures by a differential reaction rate method

1989 ◽  
Vol 334 (3) ◽  
pp. 261-265 ◽  
Author(s):  
Manuel Carmona ◽  
Manuel Silva ◽  
Dolores Perez-Bendito
Keyword(s):  
Reaction Rate ◽  
Stopped Flow ◽  
Differential Reaction ◽  
Rate Method

Automated Determination of Crude Protein, Phosphorus, Calcium, Iron, and Magnesium in Feeds by Using Stopped-Flow Analyzer

1983 ◽  
Vol 66 (1) ◽  
pp. 188-196
Author(s):  
Michael A Koupparis ◽  
Eleftherios P Diamandis ◽  
Howard V Malmstadt
Keyword(s):  
Crude Protein ◽  
Reaction Rate ◽  
Stopped Flow ◽  
Relative Standard ◽  
Rate Method ◽  
Blue Reaction ◽  
Calcium Iron ◽  
Phosphomolybdenum Blue ◽  
Feed Samples

Abstract Methods are described for determination of crude protein, phosphorus, calcium, iron, and magnesium in feeds, using an automated microprocessor-based stopped-flow analyzer. Crude protein is determined by a reaction-rate procedure based on the ammonia- sodium phenate-hypochloride Berthelot reaction. Phosphorus determination is based on a phosphomolybdenum blue reaction-rate method. o-Cresolphthalein complexone, ferrozine, and calmagite are used as colorimetric reagents for calcium, iron, and magnesium, respectively. The methods are precise with relative standard deviations less than 1%, rapid with analysis rates of 110-266 samples per hour, sensitive, and require less than 1 mL sample and reagent volumes. Results for feed samples are comparable with those obtained by official AOAC methods.

Reaction rate method for determination of nitrite by applying a stopped-flow technique

1998 ◽  
Vol 376 (3) ◽  
pp. 331-337 ◽  
Author(s):  
I.A. Pettas ◽  
S.I. Lafis ◽  
M.I. Karayannis
Keyword(s):  
Reaction Rate ◽  
Stopped Flow ◽  
Rate Method

scholarly journals Construction and evaluation of an automated flow injection-stopped flow analyser for multipoint reaction rate spectrophotometric methods. Determination of ammonia nitrogen, creatinine and phosphate

1991 ◽  
Vol 13 (5) ◽  
pp. 199-207 ◽  
Author(s):  
Constantinos A. Georgiou ◽  
Michael A. Koupparis
Keyword(s):  
Flow Injection ◽  
Reaction Rate ◽  
Assembly Language ◽  
Ammonia Nitrogen ◽  
Stopped Flow ◽  
Data Sampling ◽  
Ramp Generator ◽  
Spectrophotometric Methods ◽  
Blue Reaction

The construction and evaluation of a fully automated Flow Injection-Stopped Flow (FI-SF) spectrophotometric analyser is described. A microcomputer (Rockwell AIM 65) is used to control the analyser (sample injection, stop and start of the pump) through a suitable interface. Data acquisition is achieved using a 12 bit ADC card and a suitable subroutine in 6502 assembly language, allowing data sampling at a frequency of 7.5 kHz. The measurement interface and software were evaluated using a voltage ramp generator. A precision of 0.02-1.1% RSD (N =10) was obtained for voltage ramps in the range of 1-37 mVs-1. The FI-SF analyser was evaluated in routine analysis by developing FI-SF kinetic spectrophotometric methods for the determination of ammonia nitrogen (20-250 ppm, 0.4-2.5% RSD) based on the Berthelot reaction, creatinine (20-220 ppm, 0.9-3.6% RSD) based on the Jaffé reaction, and phosphate (5-30 ppm, 1.0-3.3% RSD) based on the phosphomolybdenum blue reaction. The reaction rate is measured by linear fitting of multiple absorbance readings vs time. Algorithms for automated estimation of the residence time, the linear range of the reaction curve, and data treatment are presented.

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

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.

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.

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.

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