A New and Rapid Determination of Pyridinium Aldoximes in Blood and Urine

1969 ◽  
Vol 15 (1) ◽  
pp. 72-83 ◽  
Author(s):  
William A Groff ◽  
Robert I Ellin
Keyword(s):  
Standard Deviation ◽  
Transfer Rate ◽  
Rapid Determination ◽  
Accurate Method ◽  
Small Sample ◽  
Basic Solution ◽  
Pyridinium Oximes ◽  
Average Variation ◽  
The Mean

Abstract A rapid and accurate method for analyzing pyridinium oximes—N-methylpyridinium-2-aldoxime chloride, N,N'-trimethylene-(pyridinium-4-aldoxime) dihalide, and N,N'-oxydimethyl-(pyridinium-4-aldoxime) dichloride—in plasma, urine, and whole blood is described. The method is completely automated and requires small sample volumes. Concentrations ranging from 3 to 120 µEq./L. in biologic fluids can be determined at a rate of 40 samples per hour. This technic can be applied to oximes which are unstable in basic solution. The average variation of the oxime concentration used to establish calibration curves, as determined by the ratio of the standard deviation to the mean, was ± 1.5%. Plasma and albumin increase the transfer rate of the oximes through the dialyzing membrane. Theoretical concentrations to explain this phenomenon are presented.

Determination of Piperazine in Feeds

1967 ◽  
Vol 50 (2) ◽  
pp. 268-273 ◽  
Author(s):  
M F Loucks ◽  
Leo Nauer
Keyword(s):  
Standard Deviation ◽  
Confidence Limit ◽  
Colorimetric Method ◽  
Alcoholic Solution ◽  
Critical Factors ◽  
Colored Complex ◽  
Collaborative Studies ◽  
Average Variation ◽  
The Mean

Abstract Collaborative studies were continued on a modification of the p-benzoquinone colorimetric method proposed by Cavett and Heotis for determining piperazine in feeds. Piperazine is extracted from the feed with water and then reacted with a buffered, hot, alcoholic solution of p-benzoquinone to form a colored complex. Absorbance is measured spectrophotometrically at 490 mμ. Control of the several critical factors, including pH of the solution and time and temperature for the reaction, is necessary. Results indicate a standard deviation (<r) of ± 0.012% and a 95% confidence limit ( 2 o-) of ± 0.024% with an average variation of ± 10%. The mean recovery was 97%. It is recommended that the method be adopted as official, first action

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.

scholarly journals Solid-Phase Extraction and Gas Chromatography with Mass Spectrometric Determination of Capsaicin and Some of Its Analogues from Chili Peppers (Capsicum spp.)

1999 ◽  
Vol 82 (6) ◽  
pp. 1399-1405 ◽  
Author(s):  
Philemon Manirakiza ◽  
Adrian Covaci ◽  
Paul Schepens
Keyword(s):  
Gas Chromatography ◽  
Quantitative Determination ◽  
Solid Phase ◽  
Accurate Method ◽  
Mass Spectrometric ◽  
Phase Extraction ◽  
Capsicum Spp ◽  
The Mean ◽  
Chili Peppers

Abstract A rapid and accurate method has been developed for the quantitative determination of capsaicin and its most important analogues, dihydrocapsaicin and nordihydrocapsaicin in chili peppers. These components were extracted with methylene chlo ride and separated from interfering substances with activated charcoal. Further cleanup on Florisil cartridges and elution with ethyl acetate were performed before gas chromatographic with mass spectrometric quantitation. The concentrations found were 440 ± 64 μg/g capsaicin, 81 ± 10 μg/g dihydrocapsaicin, and 11 ± 2 μg/g nordihydrocapsaicin. The mean recovery values for triplicate analysis were between 85-94%.

Colorimetric Method for Rapid Determination of Serum Arginase

1967 ◽  
Vol 13 (10) ◽  
pp. 900-908 ◽  
Author(s):  
Brigitta Mellerup
Keyword(s):  
Rapid Determination ◽  
Colorimetric Method ◽  
Normal Range ◽  
Clinical Routine ◽  
Mean Values ◽  
Enzymatic Formation ◽  
Significant Difference ◽  
The Mean ◽  
Normal Men

Abstract A method for the determination of serum arginase is given which combines the enzymatic formation of urea with the sensitive method of Coulombe (1) for measuring this substance. This procedure allows more accurate determinations in the normal range than do previous methods described and is convenient for clinical routine. Significant difference is found between the mean values of normal men and women, 3.9 units/L. for the former and 2.9 units/L. for the latter.

Rapid determination of Ti in TiO2 by ICP OES

2016 ◽  
Vol 8 (34) ◽  
pp. 6463-6467 ◽  
Author(s):  
E. J. Dos Santos ◽  
M. P. Dos Santos ◽  
A. B. Herrmann ◽  
R. E. Sturgeon
Keyword(s):  
Rapid Determination ◽  
Accurate Method ◽  
Icp Oes

An improved, precise and accurate method for the quantitation of Ti by ICP OES in TiO2 pigments and related materials is proposed.

Fluorometric Determination of Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Food Samples ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Relative Standard ◽  
The Mean

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.

Radioisotope Dilution Technique for Determination of Vitamin B12 in Foods

1982 ◽  
Vol 65 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Patrick J Casey ◽  
Keevin R Speckman ◽  
Frank J Ebert ◽  
William E Hobbs
Keyword(s):  
Standard Deviation ◽  
Vitamin B12 ◽  
Relative Standard Deviation ◽  
Extraction Procedure ◽  
Dilution Technique ◽  
Microbiological Method ◽  
Relative Standard ◽  
Wide Range ◽  
The Mean

Abstract A radioisotope dilution (RID) method for the determination of vitamin B12 is presented. The method combines a standard extraction procedure (AOAC 43.108,12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analyses on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B12 content determined by the RID method was 8.01 μg/100 g vs imean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983.

A simple spectroturbidimetric method for the determination of the fat content of homogenized ice-cream mixes

1962 ◽  
Vol 29 (1) ◽  
pp. 47-53 ◽  
Author(s):  
J. D. S. Goulden ◽  
P. Sherman
Keyword(s):  
Standard Deviation ◽  
Ice Cream ◽  
Fat Content ◽  
Fat Globule ◽  
The Mean ◽  
Simple Filter

SummaryA rapid spectroturbidimetric method for the determination of the fat content of homogenized ice-cream mixes using a simple filter absorptiometer has been devised. Turbidities are measured at two different wavelengths to allow for changes in the degree of homogenization. The standard deviation of the differences from the values obtained by the Werner-Schmid method was found to be 2·5% of the mean fat content value. The method also enables the mean fat globule diameter to be determined.

Ion Exchange Separations and Atomic Absorption Determination of Trace Metals in Ores after Basic Fusion

1972 ◽  
Vol 26 (2) ◽  
pp. 302-305 ◽  
Author(s):  
T. W. Freudiger ◽  
C. T. Kenner
Keyword(s):  
Standard Deviation ◽  
Ion Exchange ◽  
Metal Ions ◽  
Atomic Absorption ◽  
Strong Acid ◽  
Ion Exchange Resin ◽  
High Concentration ◽  
The Mean ◽  
Trace Constituents

The determination of trace constituents in ores by atomic absorption after basic fusion and solution in strong acid is erratic due to the light scattering and aspirator clogging of the high concentration of sodium salts. The sodium is separated from the trace constituents using a column procedure and an iminodiacetate chelating ion exchange resin which will retain di- and trivalent metal ions at pH values above 6.0 but will not retain alkali metal ions. The trace constituents are determined by atomic absorption after elution with HCl. The precision (standard deviation of the mean) of the atomic absorption method is increased at least fivefold by the resin separation and the method is applicable to concentrations in the low ppm range. The standard deviation of the mean for an NBS sample containing 0.007% Cu is 0.0004%.

scholarly journals Placental Transfer of Rilpivirine in anEx VivoHuman Cotyledon Perfusion Model

2015 ◽  
Vol 59 (5) ◽  
pp. 2901-2903 ◽  
Author(s):  
Laurent Mandelbrot ◽  
Dominique Duro ◽  
Emilie Belissa ◽  
Gilles Peytavin
Keyword(s):  
Steady State ◽  
Standard Deviation ◽  
Transfer Rate ◽  
Placental Transfer ◽  
Transcriptase Inhibitor ◽  
High Rate ◽  
Nonnucleoside Reverse Transcriptase Inhibitor ◽  
Perfusion Model ◽  
The Mean ◽  
Reverse Transcriptase Inhibitor

ABSTRACTPlacental transfers of the HIV nonnucleoside reverse transcriptase inhibitor rilpivirine were investigated in 8 term human cotyledons perfused with rilpivirine (400 ng/ml) in the maternal-to-fetal direction. The mean fetal transfer rate (FTR) (fetal/maternal concentration at steady state from 15 to 90 min) was 26% ± 8% (mean ± standard deviation), and the clearance index (rilpivirine FTR/antipyrine FTR) was 61% ± 20%. This shows that rilpivirine crosses the placenta at a relatively high rate, suggesting that the fetus is exposed to the compound during treatment of the mother.

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