scholarly journals A New Tonometric Method for the Determination of Dissolved Oxygen and Carbon Dioxide in Small Samples

1959 ◽  
Vol 36 (1) ◽  
pp. 177-190
Author(s):  
J. D. JONES
Keyword(s):  
Carbon Dioxide ◽  
Dissolved Oxygen ◽  
Present Method ◽  
Close Agreement ◽  
Small Samples ◽  
Percentage Difference ◽  
Winkler Method ◽  
The Mean

1. A microtonometric method is described whereby tensions of carbon dioxide, oxygen and nitrogen can be determined in fluid samples of 0.3 ml. volume or less, each determination taking 20-25 min. 2. Replicate determinations of the tensions of carbon dioxide, oxygen and nitrogen give maximum coefficients of variability of 3.0, 2.2 and 1.2%, respectively. 3. A comparison of the present method with a micro-Winkler method for the determination of dissolved oxygen shows a close agreement; the mean percentage difference being 3.0.

Determination of Maleic Hydrazide Residues in Tobacco and Vegetables

1973 ◽  
Vol 56 (5) ◽  
pp. 1164-1172
Author(s):  
Milan Ihnat ◽  
Robert J Westerby ◽  
Israel Hoffman
Keyword(s):  
Standard Deviation ◽  
Present Method ◽  
Maleic Hydrazide ◽  
Collaborative Study ◽  
Official Method ◽  
Sample Weight ◽  
Relative Standard ◽  
The Mean ◽  
Pipe Tobacco

Abstract The distillation-spectrophotometric method of Hoffman for determining maleic hydrazide has been modified to include a double distillation and was applied to the determination of 1–30 ppm maleic hydrazide residues in tobacco and vegetables. Recoveries of 1–23 μg added maleic hydrazide were independent of weight of maleic hydrazide, but did depend on sample and sample weight. The following recoveries were obtained from 0.5 g sample: pipe tobacco, 84%; commercially dehydrated potato, 83%; cigar tobacco, 81%; dried potato, 76%; fluecured tobacco, 73%; dried carrot, 71%. In the absence of sample, the recovery was 82%. When appropriate standard curves were used, maleic hydrazide levels determined in tobacco samples were essentially independent of sample weight in the range 0.1–3 g. The mean relative standard deviation for a variety of field-treated and fortified tobacco samples containing 1–28 ppm maleic hydrazide was 3%. The precision and sensitivity of this procedure seem to be substantial improvements over official method 29.111–29.117. It is recommended that the present method be subjected to a collaborative study.

THE DENSITY OF CARBON DIOXIDE

1930 ◽  
Vol 2 (6) ◽  
pp. 388-395 ◽  
Author(s):  
D. LeB. Cooper ◽  
O. Maass
Keyword(s):  
Carbon Dioxide ◽  
Molecular Weight ◽  
Pressure Range ◽  
Atomic Weight ◽  
Mean Value ◽  
Two Temperatures ◽  
The Mean

Modifications are described by the Maass and Russel method for the determination of the densitites of gases which permit an accuracy of about one part in 10,000. The determination has been made of the density of carbon dioxide at two temperatures and over a pressure range of 75 to 25 cm. of mercury. The mean value obtained for the molecular weight of carbon dioxide at zero pressure is 44.0033 ± 0.002, from which the atomic weight of carbon is found to be 12.0033 ± 0.002.

Automatic Estimation of Urea Using Urease and Alkaline Phenol

1966 ◽  
Vol 12 (6) ◽  
pp. 360-368 ◽  
Author(s):  
B W Wilson
Keyword(s):  
Diffusion Type ◽  
Manual Method ◽  
Automatic Estimation ◽  
Percentage Difference ◽  
The Mean ◽  
Level Of Significance ◽  
Automated Determination

Abstract A method for the automated determination of urea in plasma and urine, using urease and alkaline phenol, proved to have the advantages of speed and precision when compared with a manual method of the diffusion type. The mean percentage difference between results of the two methods did not differ from zero at the 1% level of significance when examined by the † test.

Infrared Mean Absorption Coefficients of Luminous Flames and Smoke

1978 ◽  
Vol 100 (2) ◽  
pp. 235-239 ◽  
Author(s):  
G. L. Hubbard ◽  
C. L. Tien
Keyword(s):  
Carbon Dioxide ◽  
Water Vapor ◽  
Absorption Coefficient ◽  
Infrared Radiation ◽  
Dominant Species ◽  
Close Agreement ◽  
Simple Procedure ◽  
Absorption Coefficients ◽  
Carbon Soot ◽  
The Mean

A simple procedure has been developed for the calculation of the Planck mean emission and absorption coefficients and the Rosseland mean absorption coefficient for infrared radiation of the soot-gas mixtures commonly occurring in luminous flames and smoke. Specific results are presented for mixtures involving carbon dioxide, water vapor and carbon soot, the dominant species in most combustion systems. The close agreement between the various averages clearly demonstrates the usefulness of the mean absorption coefficient concept for applications.

Determination of dissolved oxygen: a comparison of some already proposed modifications of the winkler method

1981 ◽  
Vol 16 (3-4) ◽  
pp. 219-221 ◽  
Author(s):  
A. P. P. Toledo ◽  
J. F. Carvalho ◽  
E. S. Miazaki ◽  
J. A. Souza
Keyword(s):  
Dissolved Oxygen ◽  
Winkler Method

Spectrophotometric Determination of Dissolved Oxygen Concentration in Water

1974 ◽  
Vol 31 (9) ◽  
pp. 1529-1530 ◽  
Author(s):  
W. S. Duval ◽  
P. J. Brockington ◽  
M. S. von Melville ◽  
G. H. Geen
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Spectrophotometric Determination ◽  
Iodine Concentration ◽  
Colorimetric Determination ◽  
Dissolved Oxygen Concentration ◽  
Winkler Method ◽  
Time Required

A modification of the Winkler method which increases precision while decreasing time required for oxygen analysis is described. The technique involves colorimetric determination of liberated iodine concentration at 287.5 nm.

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