Enzymatic determination of thiamin pyrophosphate with a carbon dioxide membrane electrode

1983 ◽  
Vol 55 (12) ◽  
pp. 1929-1933 ◽  
Author(s):  
Purneshwar. Seegopaul ◽  
Garry A. Rechnitz
Keyword(s):  
Carbon Dioxide ◽  
Membrane Electrode ◽  
Enzymatic Determination ◽  
Thiamin Pyrophosphate

Determination of total carbon dioxide in serum and plasma using a carbonate ion-selective membrane electrode

1977 ◽  
Vol 76 (3) ◽  
pp. 295-307 ◽  
Author(s):  
Garry A. Rechnitz ◽  
Gladys June Nogle ◽  
Mary R. Bellinger ◽  
Helen Lees
Keyword(s):  
Carbon Dioxide ◽  
Total Carbon ◽  
Membrane Electrode ◽  
Carbonate Ion ◽  
Selective Membrane

Automated Enzymatic Determination of L-Lysine in Grain

1974 ◽  
Vol 57 (5) ◽  
pp. 1098-1103 ◽  
Author(s):  
Larry L Wall ◽  
Charles W Gehrke
Keyword(s):  
Carbon Dioxide ◽  
Free Water ◽  
Dialysis Membrane ◽  
Standard Curve ◽  
Carbon Dioxide Gas ◽  
Automated Method ◽  
Enzymatic Determination ◽  
Exchange Data ◽  
Good Agreement

Abstract An accurate and precise automated method has been developed for the determination of lysine in grain hydrolysates. The enzyme L-lysine decarboxylase specifically catalyzes removal of the carboxyl group from L-lysine, producing an amine and carbon dioxide. This reaction has been automated. The carbon dioxide produced was selectively dialyzed into a stream of carbonate with phenolphthalein by a dialysis block containing a carbon dioxide gas dialysis membrane. Ground samples of grain (250 mg) were hydrolyzed 20 hr in 25 ml 6N HC1 at 110°C Aliquots were evaporated to dryness under nitrogen with low heat. The samples were redissolved in carbon dioxide-free water and the enzyme was suspended in pH 6.5 phosphate buffer. Analyses were made at 30/hr with a sample-to-wash ratio of 4:1. A standard curve with a range of 0 to 90 ppm lysine was expanded to full scale on the recorder. From the comparative height of each sample peak vs. the standard curve, the per cent lysine in the original sample can be calculated. Repeated analyses on 15 samples, 5 each of corn, mungbeans, and soybeans, by the automated method showed that the precision was good, and the results were in good agreement with classical ion exchange data. The automated method for lysine in corn has been used in our laboratory to analyze 1500–2000 corn samples each year for the last 5 years.

Enzymatic Determination of Carbon Dioxide in Lightly Carbonated Wines

1962 ◽  
Vol 45 (3) ◽  
pp. 627-629
Author(s):  
Robert L Morrison
Keyword(s):  
Carbon Dioxide ◽  
Enzymatic Determination

Colorimetric Enzymatic Determination of Serum Total Carbon Dioxide, as Applied to the Vickers Multichannel 300 Discrete Analyzer

1975 ◽  
Vol 21 (8) ◽  
pp. 1093-1101 ◽  
Author(s):  
Kenneth A Norris ◽  
Alan R Atkinson ◽  
William G Smith
Keyword(s):  
Carbon Dioxide ◽  
Serum Protein ◽  
Open System ◽  
Phosphoenolpyruvate Carboxylase ◽  
Diazonium Salt ◽  
Colorimetric Assay ◽  
Total Carbon ◽  
Excellent Correlation ◽  
Enzymatic Determination

Abstract Phosphoenolpyruvate carboxylase (EC 4.1.1.31) has been used in developing a simple, inexpensive colorimetric assay for serum total carbon dioxide in an open system. The oxaloacetate formed by the action of the enzyme on bicarbonate and phosphoenolpyruvate is measured by use of the diazonium salt of Fast Violet B. Interferences from bilirubin, pyruvate, and drugs are negligible. Acetoacetate interference is significant only in highly ketotic samples, and a serum blank corrects for it. Serum protein interference is equivalent to 3.3 ± 1.25 mmol of CO2 per liter and hence is sufficiently constant to be corrected for by use of a serum standard or serum blank. The method has been applied to the Vickers M-300 and D-300 systems and within-batch standard deviations of ±0.1 to ±0.6 mmol/liter have been observed. Excellent correlation with orthodox techniques has been obtained.

Enzymatic Determination of Carbon Dioxide in Lightly Carbonated Wines—1962 Collaborative Study

1963 ◽  
Vol 46 (2) ◽  
pp. 288-289
Author(s):  
Robert L Morrison
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Collaborative Study ◽  
Enzymatic Method ◽  
Titrimetric Method ◽  
Enzymatic Determination

Abstract The titrimetric method for determining carbon dioxide in wine using carbonic anhydrase (presented at the 1961 AOAC Meeting) was studied collaboratively. Six laboratories analyzed 20 samples by the enzymatic method. Results varied considerably, and it is recommended that the method be studied collaboratively for another year.

Enzymatic Determination of Carbon Dioxide in Lightly Carbonated Wine—1963 Collaborative Study

1964 ◽  
Vol 47 (4) ◽  
pp. 711-712
Author(s):  
Robert L Morrison
Keyword(s):  
Carbon Dioxide ◽  
Carbonic Anhydrase ◽  
Sample Preparation ◽  
Collaborative Study ◽  
Titrimetric Method ◽  
Enzymatic Determination ◽  
Second Year ◽  
Made In

Abstract The titrimetric method for determining carbon dioxide in wine, using carbonic anhydrase, was studied collaboratively for the second year. Sample preparation was improved, and two modifications were made in the apparatus: a 5 ml instead of a 10 ml buret and a 25—30 ml automatic pipet instead of a 50 ml buret. Results were good, and it is recommended that the method be adopted as official, first action.

Enzymatic Determination of Hydroxysteroids in Human Skin Surface Lipids1

1963 ◽  
Vol 41 (5) ◽  
pp. 265-268 ◽  
Author(s):  
Thomas J Cook ◽  
Allan L Lorincz ◽  
Alan R Spector
Keyword(s):  
Human Skin ◽  
Skin Surface ◽  
Enzymatic Determination
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