Milk. Quantitative determination of bacteriological quality. Guidance for establishing and verifying conversion relationship between routine method results and anchor method results

2015 ◽  
Keyword(s):  
Quantitative Determination ◽  
Routine Method ◽  
Bacteriological Quality

ROUTINE DETERMINATIONS OF 17-KETOSTEROIDS AND PORTER-SILBER CHROMOGENS COMPARED WITH THE CHROMATOGRAPHIC MEASUREMENT OF GROUPED AND INDIVIDUAL STEROIDS

1964 ◽  
Vol 46 (4) ◽  
pp. 552-562 ◽  
Author(s):  
Ingrid Ernest ◽  
Britt Håkansson ◽  
Jörgen Lehmann ◽  
Björn Sjögren
Keyword(s):  
Urinary Excretion ◽  
Quantitative Determination ◽  
Column Chromatography ◽  
Chromatographic Separation ◽  
Enzyme Hydrolysis ◽  
Routine Method ◽  
Urinary Steroids ◽  
Urinary Content ◽  
Chromatographic Measurement

ABSTRACT The accuracy of two routine methods for the determination of urinary steroids – 17-ketosteroids (17-KS) and Porter-Silber chromogens – has been investigated by chromatographic separation and quantitative determination of individual 17-KS and Porter-Silber reacting steroids in 141 urine samples. For this purpose urine was submitted to enzyme hydrolysis and subsequent solvolysis. The pertinent steroids were separated by column chromatography into three groups, 11-deoxy-17-KS, 11-oxy-17-KS and Porter-Silber reacting steroids. The final separation was accomplished by paper chromatography. As a mean, the urinary excretion of true 17-KS corresponded to about 40–50 per cent of the routine figures. Due to non specific chromogens, individual routine figures were completely unreliable and probably had no more significance than showing a difference between a high and a low urinary content of 17-KS A true figure, however, was never higher than that indicated by the routine method. The routine method for determination of Porter-Silber chromogens also overestimated the urinary content of steroids, the true excretion of Porter-Silber steroids being, on an average, about 25 % lower. Again, the significance of individual determinations was low. The determination of 17-KS and Porter-Silber steroids by column chromatography was found to be rather simple and reliable as only minor amounts of unspecific chromogens were included in the results. Moreover with this method, the 17-KS were separated into 11-deoxy-17-KS and 11-oxy-17-KS.

scholarly journals Methods of Quantitative Determination of Catechol in Cigarette Smoke Condensate/Methoden der quantitativen Bestimmung des Brenzcatechins im Cigarettenrauch

1965 ◽  
Vol 3 (4) ◽  
Author(s):  
P. Waltz ◽  
M. Häusermann ◽  
A. Krull
Keyword(s):  
Absorption Spectrum ◽  
Quantitative Determination ◽  
Cigarette Smoke ◽  
Bathochromic Shift ◽  
High Specificity ◽  
Methanol Solution ◽  
Routine Method ◽  
Cigarette Smoke Condensate ◽  
Polyamide Powder

AbstractThree methods of quantitative determination of catechol in cigarette smoke condensate are presented. The procedures are based on:a.Column chromatography of a smoke condensate solution in chloroform over polyamide powder, followed by elution with ethyl acetate and a spectrophotometric measure in methanol solution;b.Liquid-liquid partitions of the smoke condensate, followed by a spectrophotometric measure based on a bathochromic shift of the absorption spectrum of catechol; andc.Vapour-phase chromatography of the phenolic smoke components in the form of their methyl ethers. The procedure a. is best suited as a routine method, as it is easy to execute and gives fairly accurate and precise results. The procedures b. and c. both give less reproducible results, and c. shows insufficient analytical yields. Their advantages are the rapid execution of method b. and the high specificity of method c.Contents between 200 and 500 µg of catechol per cigarette were found in the smoke of cigarettes.

Quantitative determination of longitudinal and transverse cross-relaxation rates

1999 ◽  
Vol 96 (9/10) ◽  
pp. 1608-1615
Author(s):  
T. E. Malliavin ◽  
H. Desvaux ◽  
M. A. Delsuc
Keyword(s):  
Quantitative Determination ◽  
Cross Relaxation ◽  
Relaxation Rates
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