scholarly journals Modified Method of Krejnin and Murri for the Determination of Absolute Declinations

1990 ◽  
Vol 141 ◽  
pp. 95-95
Author(s):  
S.A. Tolchelnikova-Murri
Keyword(s):  
Equatorial Zone ◽  
Micrometer Screw ◽  
Modified Method ◽  
Scale Error ◽  
Systematic Effects ◽  
Global Reduction ◽  
Improve Planning

Krejnin and Muni's method (1973) enablesenables one to derive absolute declinations of stars in a narrow equatorial zone |δ| < 10′ from observations near the Earth's equator |ϕ| < 10′. Some systematic effects, including the errors of the value of the micrometer screw for two equatorial instruments (or the scale error if one of the instruments is a PZT), might be determined if a global reduction is used for the original observations from the equator and from those of an astrolabe at latitude |ϕ| ∼ 20° to 23°. Astrolabes—especially photoelectric ones (Hu 1988) are considered to be the most efficient for determination of absolute declinations of stars and absolute latitudes of the instruments in Tolchel'nikova-Murri (1985).In Izv. GAO No. 206 the method will be published as well as the criterion for estimating the efficiency of different programs, which is required to improve planning in astrometry.

Adaptation of the AOAC Fluorine Method for Determining Fluoride in Fish Protein Concentrate

1970 ◽  
Vol 53 (1) ◽  
pp. 3-6
Author(s):  
R. Bruce Klemm ◽  
Mary E. Ambrose Klemm
Keyword(s):  
Steam Distillation ◽  
Silica Sand ◽  
Official Method ◽  
Protein Concentrate ◽  
Fish Protein ◽  
Direct Titration ◽  
Modified Method ◽  
Aoac Official ◽  
Aoac Official Method

Abstract The AOAC official method, 24.029–24.035, for the determination of fluorine in foods was modified slightly to o btain quantitative recoveries of fluorine from samples of fish protein concentrate (FPC). The most important alterations include the use of steam distillation, the addition of finely ground silica sand in the distillation, a decrease in the distillation temperature, and the utilization of direct titration. Recoveries of fluoride added to FPC before ashing, using this modified method, averaged 96.0 ± 3.0%. Our results are in agreement with those of several other analysts who used a variety of methods.

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.

Collaborative Study of a Modified Method for the Determination of Aflatoxins in Copra, Copra Meal, and Coconut

1971 ◽  
Vol 54 (4) ◽  
pp. 874-878
Author(s):  
F J Baur ◽  
J C Armstrong
Keyword(s):  
Aflatoxin B1 ◽  
Quantitative Measurement ◽  
Collaborative Study ◽  
Copra Meal ◽  
Modified Method

Abstract A collaborative study, in which 19 laboratories participated, was conducted on a modified method for the determination of aflatoxins in 2 copra samples, one naturally contaminated, and 4 samples of naturally contaminated copra meal. The sensitivity and precision of the modified method for aflatoxin B1 and total aflatoxins were comparable to the official methods for peanuts and peanut products. Aflatoxins B2, G1, and G2 were reported by most of the laboratories, but background interferences made quantitative measurement less reliable than for B1. The method as it presently stands is also applicable to the analysis of coconut. The method has been adopted as official first action; further study will be directed toward improved precision for analysis of aflatoxins B2, G1, and G2.

scholarly journals A Modified Method for Determination of Lumefantrine in Human Plasma by HPLC-UV and Combination of Protein Precipitation and Solid-Phase Extraction: Application to a Pharmacokinetic Study

2010 ◽  
Vol 5 ◽  
pp. ACI.S4431 ◽  
Author(s):  
Liusheng Huang ◽  
Patricia S. Lizak ◽  
Anura L. Jayewardene ◽  
Florence Marzan ◽  
Ming-Na Tina Lee ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Human Plasma ◽  
Solid Phase ◽  
Internal Standard ◽  
Pharmacokinetic Interaction ◽  
Gradient Elution ◽  
Protein Precipitation ◽  
Phase Extraction ◽  
Modified Method

An HPLC-UV method was developed and validated for the determination of lumefantrine in human plasma. Lumefantrine and its internal standard halofantrine were extracted from plasma samples using protein precipitation with acetonitrile (0.2% perchloric acid) followed by solid-phase extraction with Hypersep C8 cartridges. Chromatographic separation was performed on a Zorbax SB-CN HPLC column (3.0 × 150 mm, 3.5 μm) with water/methanol (0.1% TFA) as the mobile phases in a gradient elution mode. Detection was performed using UV/vis detector at λ = 335 nm. The method showed to be linear over a range of 50-10,000 ng/mL with acceptable intra- and inter-day precision and accuracy. The mean recoveries were 88.2% for lumefatrine and 84.5% for the I.S. The internal standard halofantrine is readily available from commercial sources. This method was successfully applied to a pharmacokinetic interaction study between a first-line antimalarial combination (artemether—lumefantrine) and antiretroviral therapy.

A Modified Method for Determination of Uropepsin

1959 ◽  
Vol 5 (2) ◽  
pp. 135-141
Author(s):  
Konstantin E Arensburger
Keyword(s):  
Basic Principles ◽  
Modified Method ◽  
Original Specimen ◽  
Other Substances

Abstract The incorrect high values in the determination of uropepsin results from the color of the original specimen. Evidently incubation changes other substances that are present in the urine and then react with the reagent or otherwise add to the absorbance at the determination wavelength. The method presented gives results that are considerably closer to correct. The basic principles involved in the determination of uropepsin by Gray and his associates have not been altered by this modification.

Modified Method for Electron Capture Gas-Liquid Chromatographic Determination of Diethylstilbestrol Residues in Urine of Fattened Bulls

1983 ◽  
Vol 66 (5) ◽  
pp. 1230-1233
Author(s):  
Athanasios E Tirpenou ◽  
Stylianos D Kilikidis ◽  
Athanasios P Kamarianos
Keyword(s):  
Sodium Hydroxide ◽  
Electron Capture ◽  
Silica Gel ◽  
Chromatographic Determination ◽  
Trifluoroacetic Anhydride ◽  
Phenolic Fraction ◽  
Modified Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract A gas-liquid chromatographic (GLC) method with electron capture (EC) detection was developed fof determining diethylstilbestrol residues in the urine of fattened bulls. Diethylstilbestrol (DES) is extracted into benzene, and then into IN sodium hydroxide. The pH of the phenolic fraction (alkaline phase) is adjusted to 10.2 and DES is extracted again into benzene. Sample extracts are cleaned up on silica gel. Trifluoroacetic anhydride (TFAA) is used as acylation reagent, and the derivatized sample is chromatographed on a 3% OV-17 column and measured with a 63Ni EC detector. The method is suitable for determining residues at levels as low as 2 ppb.

scholarly journals A Simplified Modification of the AOAC Official Method for Determination of Total Dietary Fiber Using Newly Developed Enzymes: Preliminary Interlaboratory Study

2007 ◽  
Vol 90 (1) ◽  
pp. 225-237 ◽  
Author(s):  
Kenichiro Kanaya ◽  
Shusaku Tada ◽  
Bunpei Mori ◽  
Rie Takahashi ◽  
Sachie Ikegami ◽  
...  
Keyword(s):  
Dietary Fiber ◽  
Enzymatic Digestion ◽  
Interlaboratory Study ◽  
Total Dietary Fiber ◽  
Stabilizing Agents ◽  
Modified Method ◽  
Relative Standard ◽  
Aoac Method ◽  
Standard Deviations

Abstract A preliminary interlaboratory study was conducted to evaluate the validity of the modified AOAC method for determination of total dietary fiber by Tada and Innami, in which the 3-step enzymatic digestion process in AOAC Method 991.43 is modified to a 2-step process without pH adjustment. Total dietary fiber contents in 8 representative foodstuffs were measured using both the original AOAC Method 991.43 and the modified method in 6 research facilities in Japan. Repeatability relative standard deviations, reproducibility relative standard deviations, and Horwitz ratio values from the modified method were equivalent to those from AOAC Method 991.43, except in the rice sample. However, this exceptional case shown in the modified method was entirely dissolved by the addition of α-amylase stabilizing agents. The modified method, which shortens the process of enzymatic digestion from 3 to 2 steps and in which only reaction temperature is adjusted under the same pH, was found not only to give accurate values comparable to the original method, but also to substantially reduce the labor required by the laboratory staff in the process of routine analysis. This study revealed that the validity of the modified method was further ensured by adding α-amylase stabilizing agents to the reaction system.

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