Separation of analytes as a source of information

1989 ◽  
Vol 54 (7) ◽  
pp. 1770-1776 ◽  
Author(s):  
Karel Eckschlager
Keyword(s):  
Information Entropy ◽  
Analytical Procedure ◽  
Multicomponent Analysis ◽  
Field Mapping ◽  
Amount Of Information ◽  
Source Of Information

It is shown how the amount of information gained by separation and detection or determination of several components depends on the selectivity of the analytical procedure in question. The selectivity is characterized in terms of the information entropy. Rules useful in the optimization of multicomponent analysis are derived from the results of information field mapping.

Statistical analysis of classification

1966 ◽  
Vol 24 ◽  
pp. 188-189
Author(s):  
T. J. Deeming
Keyword(s):  
Multivariate Analysis ◽  
Statistical Analysis ◽  
Classification Scheme ◽  
Analytical Procedure ◽  
Narrow Band ◽  
Scientific Research ◽  
Maximum Amount ◽  
Amount Of Information

If we make a set of measurements, such as narrow-band or multicolour photo-electric measurements, which are designed to improve a scheme of classification, and in particular if they are designed to extend the number of dimensions of classification, i.e. the number of classification parameters, then some important problems of analytical procedure arise. First, it is important not to reproduce the errors of the classification scheme which we are trying to improve. Second, when trying to extend the number of dimensions of classification we have little or nothing with which to test the validity of the new parameters.Problems similar to these have occurred in other areas of scientific research (notably psychology and education) and the branch of Statistics called Multivariate Analysis has been developed to deal with them. The techniques of this subject are largely unknown to astronomers, but, if carefully applied, they should at the very least ensure that the astronomer gets the maximum amount of information out of his data and does not waste his time looking for information which is not there. More optimistically, these techniques are potentially capable of indicating the number of classification parameters necessary and giving specific formulas for computing them, as well as pinpointing those particular measurements which are most crucial for determining the classification parameters.

Improved Method for the Determination of Ethylenebisdithiocarbamate Residues in Plants, Fruits, and Vegetables

1967 ◽  
Vol 50 (5) ◽  
pp. 1102-1108
Author(s):  
Charles F Gordon ◽  
Richard J Schuckert ◽  
William E Bornak
Keyword(s):  
Sulfuric Acid ◽  
Fruits And Vegetables ◽  
Analytical Procedure ◽  
Improved Method ◽  
Modified Method ◽  
Fungicide Residues ◽  
Crop Types ◽  
Large Representative

Abstract A modified method for the determination of dithiocarbamate fungicide residues on crops is presented. A large representative subsample of the frozen crop is blended in ice-cold deaerated water and an aliquot of the homogenate is added to the analytical apparatus containing hot 5 0% sulfuric acid. Dithiocarbamates are decomposed to evolve CS2 which is removed by a continuous gentle air-sweep from the digestion flask. Variations in technique allow the analysis of dithiocarbamate fungicide residues in several ranges, 1-10, 10-200, and 200-1000 /ig maneb. Recoveries from a wide variety of crops averaged 70 to 103%. Certain crop types present low recoveries and/or high apparent control values, but modifications in the analytical procedure are successful in solving these problems.

Statistical Description of Isotope Exchange Processes: A Multisite Model for the 18O Exchange

1982 ◽  
Vol 37 (11-12) ◽  
pp. 1161-1169 ◽  
Author(s):  
Paul Rösch
Keyword(s):  
Active Site ◽  
Isotope Exchange ◽  
Analytical Procedure ◽  
Matrix Formalism ◽  
Model Calculations ◽  
Exchange Processes ◽  
Reaction Solution ◽  
Different Types ◽  
Refinement Procedure

Abstract An analytical procedure has been developed for the determination of isotope exchange processes as exemplified by the 18O exchange catalysed by enzyme-nucleotide complexes. The model is able to handle more than one type of active site per reaction solution and is also able to distinguish between different types of inequivalence of the oxygens of enzyme bound Pi. Use of transition matrix formalism and basic statistical considerations lead directly to the simple model. A data refinement procedure is introduced and model calculations are shown.

Method for the simultaneous quantification of n-hexane metabolites: application to n-hexane metabolism determination

1996 ◽  
Vol 15 (6) ◽  
pp. 497-503 ◽  
Author(s):  
T. Soriano ◽  
M. Menéndez ◽  
P. Sanz ◽  
M. Repetto
Keyword(s):  
Similar Pattern ◽  
Analytical Procedure ◽  
Daily Basis ◽  
Practical Application ◽  
Simultaneous Quantification ◽  
Exposed Workers ◽  
Before And After ◽  
Time Requirements ◽  
The Difference

1 The described analytical procedure permits the simultaneous determination of the main n-hexane meta bolites in urine. 2-Hexanone, 2-hexanol, 2, 5-hexanediol and 2, 5-hexanedione, were chosen to dose the rats used in this study. All urine samples were collected and analysed on a daily basis, before and after acidic hydrolysis (pH 0.1) by GC/MS. 2-Hexanone, 2, 5-dimethylfurane, γ-valerolac tone and 2, 5-hexanedione were determined before hydro lysis ; 2-hexanol and 2, 5-hexanediol, after hydrolysis; and 5-hydroxy-2-hexanone and 4, 5-dihydroxy-2-hexanone were calculated by the difference between γ-valerolactone and 2, 5-hexanedione with and without hydrolysis, respectively. 2 A metabolic scheme was proposed reflecting the biotransformations undergone by the four compounds assayed. We consider 2, 5-dimethylfurane as a 'true metabolite' because the quantities detected were always greater before hydrolysis. 3 It has been reported that human and rat n-hexane metabolism follow a similar pattern. Therefore, as a practical application and without increasing either sample or time requirements, the simultaneous quantifi cation of the different metabolites and their excretion profile could provide better information about the metabolic situation of exposed workers than the determi nation of 2, 5-hexanedione alone. According to our experimental results, 4, 5-dihydroxy-2-hexanone itself would be a good toxicity indicator.

scholarly journals Determination of Cd, Pb and As in sediments of the Sava river by electrothermal atomic absorption spectrometry

2010 ◽  
Vol 75 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Simona Murko ◽  
Radmila Milacic ◽  
Marjan Veber ◽  
Janez Scancar
Keyword(s):  
Nitric Acid ◽  
Analytical Procedure ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Absorption Spectrometry ◽  
Magnesium Nitrate ◽  
Matrix Modifier ◽  
Reliable Determination ◽  
Sava River ◽  
The Sava River

The applicability of nitric acid, palladium nitrate and a mixture of palladium and magnesium nitrate as matrix modifiers was estimated for the accurate and reproducible determination of cadmium (Cd), lead (Pb) and arsenic (As) in sediments of the Sava River by electrothermal atomic absorption spectrometry, ETAAS. Decomposition of the samples was done in a closed vessel microwave-assisted digestion system using nitric, hydrochloric and hydrofluoric acids, followed by the addition of boric acid to convert the fluorides into soluble complexes. The parameters for the determination of Cd, Pb and As in sediments were optimized for each individual element and for each matrix modifier. In addition, two sediment reference materials were also analyzed. In determination of Cd and Pb, nitric acid was found to be the most appropriate matrix modifier. The accurate and reliable determination of Cd and Pb in sediments was possible also in the presence of boric acid. The use of a mixture of palladium and magnesium nitrate efficiently compensated for matrix effects and enabled the accurate and reliable determination of As in the sediments. Quantification of Cd and As was performed by calibration using acid matched standard solutions, while the standard addition method was applied for the quantification of Pb. The repeatability of the analytical procedure for the determination of Cd, Pb and As in sediments was ?5 % for Cd, ?4 % for Pb and ?2 % for As. The LOD values of the analytical procedure were found to be 0.05 mg/kg for Cd and 0.25 mg/kg for Pb and As, while the LOQ values were 0.16 mg/kg for Cd and 0.83 mg/kg for Pb and As. Finally, Cd, Pb and As were successfully determined in sediments of the Sava River in Slovenia.

Direct solid-phase enzymoimmunoassay of testosterone in saliva.

1989 ◽  
Vol 35 (10) ◽  
pp. 2044-2047 ◽  
Author(s):  
K Howard ◽  
M Kane ◽  
A Madden ◽  
J P Gosling ◽  
P F Fottrell
Keyword(s):  
Detection Limit ◽  
Analytical Procedure ◽  
Solid Phase ◽  
Medical Applications ◽  
Microtiter Plates ◽  
Large Numbers ◽  
Coefficients Of Variation ◽  
Serial Sampling ◽  
Direct Solid

Abstract This competitive, solid-phase enzymoimmunoassay for testosterone in saliva is carried out on microtiter plates and involves no chromatographic or extraction steps. With an overnight incubation the detection limit of the assay is 230 fg per well (16.1 pmol/L). There was a good correlation (correlation coefficient 0.95) between testosterone concentrations measured with and without prior extraction of the saliva samples. Repeated assay of three control saliva samples containing a range of testosterone concentrations (200-1000 pmol/L) gave within- and between-assay coefficients of variation of 5.5-13.2%. The analytical procedure is simple and closely resembles already published procedures for the determination of progesterone and estrone (with extraction) in saliva. One person can assay 200 samples in 24 h and the assay is suitable for reproductive and sports medical applications, particularly for projects involving serial sampling and yielding large numbers of samples.

scholarly journals Application of the Folin-Ciocalteu method to the evaluation of Salvia sclarea extracts

Pharmacia ◽  
2019 ◽  
Vol 66 (4) ◽  
pp. 209-215 ◽  
Author(s):  
Nataliia Hudz ◽  
Oksana Yezerska ◽  
Mariia Shanajda ◽  
Vladimira Horčinová Sedláčková ◽  
Piotr P. Wieczorek
Keyword(s):  
Analytical Procedure ◽  
Phenolic Content ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Optimum Conditions ◽  
Pharmaceutical Development ◽  
Salvia Sclarea ◽  
High Antioxidant Activity ◽  
High Level

Polyphenols are valuable group of phytoconstituents due to their high antioxidant activity and healing properties. Antioxidant properties of sages are attributed mainly to a high level of phenolic compounds. The aim of the present study was to elaborate an analytical procedure for the evaluation of the content of secondary metabolites of the polyphenol nature in the herb of Clary Sage (Salvia sclarea L.). Four crude extracts of Salvia sclarea herb obtained with different technologies were used to develop an analytical procedure for the total phenolic content (TPC) assay by spectrophotometric method. The optimum conditions for the analysis (time of the reaction, wavelength, and reference substances) were chosen and experimentally justified (60–80 min, 760 nm, gallic acid and rutin, respectively). Under these conditions, the developed analytical procedure is robust in the indicated time and easy for performing in phytochemical or technological laboratories. The yield of TPC from the herb of Salvia sclarea was the highest in the extracts prepared by heating at a temperature of 36–46 °C and with using the ultrasonic bath. TPC was the highest in the extract in which solvent-to-herb ratio was the least (10:1) and particle size was in the range of 2–5 mm. As a result of the studies, the analytical procedure of the determination of TPC was developed and its parameters were justified. This methodology complies with the requirements for pharmaceutical analysis to ensure the reliability of results during pharmaceutical development and routine control of Salvia sclarea extracts.

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