Collaborative Study on Assay of Sulfur Dioxide in Dried Apricots

1963 ◽  
Vol 46 (4) ◽  
pp. 618-622
Author(s):  
John E Brekke
Keyword(s):  
Sulfur Dioxide ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
New Method ◽  
Test Material ◽  
Material Recovery

Abstract The official (Monier-Williams) method for sulfur dioxide determination in food was compared with a new colorimetric method in a collaborative study. Dried apricots were the test material. Recovery of S 0 2 by the colorimetric method was found to be satisfactory The new method gave results not significantly different from the Monier- Williams volumetric assay but significantly different from the Monier-Williams gravimetric assay.

Collaborative Study on Assay of Sulfur Dioxide in Dried Fruit

1965 ◽  
Vol 48 (4) ◽  
pp. 796-801
Author(s):  
F S Nury ◽  
H R Bolin
Keyword(s):  
Sulfur Dioxide ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Dried Fruits ◽  
Dried Fruit ◽  
Test Materials ◽  
Colorimetric Procedure ◽  
Satisfactory Recovery

Abstract Sulfur dioxide analysis by official (Monier-Williams) methods was compared with a new colorimetric procedure for dried fruits. Dried peaches, pears, apples and golden raisins were the test materials. The colorimetric method was found to be neither more nor less variable than two official methods except in analysis of dried pears, took less time and was easier to perform than the official methods, and yielded satisfactory recovery of sulfur dioxide.

Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study

1990 ◽  
Vol 73 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Meat Products ◽  
Acid Oxidation ◽  
Colorimetric Determination ◽  
Mean Values ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Analytical Result

Abstract A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.

Collaborative Study Using a ZDBT Colorimetric Method for the Determination of Copper in Alcoholic Products

1967 ◽  
Vol 50 (2) ◽  
pp. 334-338
Author(s):  
Duane H Strunk ◽  
A A Andreasen
Keyword(s):  
Sulfuric Acid ◽  
Carbon Tetrachloride ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Good Precision ◽  
Determination Of Copper

Abstract Results are given on a collaborative study in which a zinc dibenzyldithiocarbamate (ZDBT) colorimetric method is used to measure copper in alcoholic products such as high wine, spirits, gin, whisky, brandy, rum, and wine. In this method, the sample is made ca 0.SN with sulfuric acid, and carbon tetrachloride containing 0.2% ZDBT is added. The colored copper-ZDBT complex is extracted in the carbon tetrachloride and measured at 438 mμ against a similar carbon tetrachloride extract of a blank. Data show good precision, and it is recommended that the ZDBT method be adopted as official, first action.

Collaborative Study of a New Method for the Extraction of Light Filth from White Flour

1972 ◽  
Vol 55 (3) ◽  
pp. 514-515
Author(s):  
Mary T Miller
Keyword(s):  
Acid Hydrolysis ◽  
Collaborative Study ◽  
Mineral Oil ◽  
New Method ◽  
White Flour

Abstract A new method for the separation of light filth from white flour is based on an autoclave-acid hydrolysis, followed by separation of light fdth elements with mineral oil in a Corning or Kilborn separator. This method is rapid and gives clean papers and good recoveries. The method has been adopted as official first action, to replace 40.045 and 40.046 for extraction of light filth from white flour.

Colorimetric Method for Carbadox in Feeds: Collaborative Study

1977 ◽  
Vol 60 (5) ◽  
pp. 1059-1063
Author(s):  
John T Goras
Keyword(s):  
Standard Deviation ◽  
Stannous Chloride ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Feed Supplement ◽  
Colored Complex ◽  
Feed Supplements ◽  
Repeatability Standard Deviation ◽  
Standard Additions ◽  
The Mean

Abstract A colorimetric method for determining carbadox in complete swine feeds and feed supplements was collaboratively studied. Carbadox is separated from feed with CHCl3-methanol (3+1) and then separated from interfering materials by a series of solvent-solvent extractions. The drug is isolated as a dry residue, reconstituted, and reacted with stannous chloride to form a colored complex that is measured at 520 nm. The method of standard additions is used to compensate for a feed or feed supplement matrix effect. Twenty-seven laboratories assayed feeds containing 0.0013, 0.0053, and 0.0242% carbadox. The repeatability standard deviation (σ0) and reproducibility standard deviation (σx) were σ0 = 0.00014%, σx = 0.00035% (29% of grand mean) for 0.0013% carbadox in feed; σ0 = 0.00025%, σx = 0.00037% (6.7% of grand mean) for 0.0053% carbadox in feed; and σ0 = 0.0019%, σx = 0.0024% (9.6% of grand mean) for 0.0242% carbadox in feed. The between-laboratory variance ratio was not significant for feeds containing 0.0013 and 0.0053% carbadox, but was significant for feeds containing 0.0242% carbadox. The mean recovery values for feeds containing 0.0013, 0.0053, and 0.0242% carbadox were 92, 104, and 103%, respectively. The method was adopted as official first action for feeds having a guaranteed potency of 0.0055% carbadox or higher.

Collaborative Study of a New Method for Extraction of Light Filth from Reconditioned (Coarsely Ground) Nutmeg

1971 ◽  
Vol 54 (3) ◽  
pp. 575-578
Author(s):  
Alberto W Vazquez
Keyword(s):  
Collaborative Study ◽  
Mineral Oil ◽  
New Method ◽  
Official Method ◽  
Collaborative Testing

Abstract A new method has been developed for extraction of light filth from coarsely ground nutmeg. Nutmeg tissue is defatted by 3 successive 10 min extractions with boiling CHCI3, after which the solvent is removed by aspiration and an isopropanol rinse. Following sieving on a No. 230 sieve and a brief deaeration and hydrolysis step in acidified boiling 60% ethanol-CaCl2, light filth elements are extracted with mineral oil from the 60% ethanol-CaCl2 mixture. Collaborative testing of the proposed method yielded satisfactory recoveries of added light filth elements. The official method for ground spices, 40.106(b), was compared in a collaborative study with the proposed method for the analysis of ground nutmeg and mace. Results were encouraging, but further study is indicated. The method as described for reconditioned nutmeg has been adopted as official first action.

Oscillopolarographic Analysis of Morestan® Residues in Valencia Orange Rind Following Thin Layer Chromatography

1966 ◽  
Vol 49 (4) ◽  
pp. 774-778
Author(s):  
Fred E Hearth ◽  
Daniel E Ott ◽  
Francis A Gunther
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Colorimetric Method ◽  
New Method ◽  
Valencia Orange ◽  
Layer Chromatography

Abstract A new method combining oscillopolarography and thin layer chromatography is described for the microdetermination of residual Morestan in Valencia orange rind; 0.5 ppm is readily detectable, but accurate quantitation is difficult below 1.0 ppm. Data obtained by this method are comparable to those from a colorimetric method.

Collaborative Study of the Spectrophotometric Determination of Phosphatase Activity in Milk Utilizing a New Alkaline Phosphatase Assay System

1972 ◽  
Vol 55 (3) ◽  
pp. 498-503
Author(s):  
D H Kleyn ◽  
C L Huang
Keyword(s):  
Systematic Error ◽  
Collaborative Study ◽  
Correlation Coefficients ◽  
New Method ◽  
Statistical Comparison ◽  
Alkaline Phosphatase Assay ◽  
Phosphatase Assay ◽  
Method Analysis ◽  
Quantitative Procedure

Abstract A quantitative procedure (modified new method) has been studied that employs phenolphthalein monophosphate as the substrate and dialysis of released phenolphthalein followed by subseqvient measurement of the dialysate in a spectrophotometer at 550 nm. Nine collaborators evaluated 6 unknown samples of milk containing various levels of rawmilk, in triplicate, by the modified new method and the Scharer modified spectrophotometric method. Analysis of variance revealed that the random error of the modified new method was almost twice that of the Scharer technique, while the systematic error of the modified new method was only about ¼ that of the latter method. Two-sample charts indicated that the systematic error of the modified new method was less than that of the Scharer method; this was verified by a statistical comparison which showed that the total analytical error was much lower for the modified new method. A linear relationship was found between the 2 methods by 5 of the collaborators; the correlation coefficients ranged from 0.993 to 0.999. Based on these results, the method has been adopted as official first action for the analysis of milk.

Extraction of Light Filth from Canned Green Leafy Vegetables: Collaborative Study

1979 ◽  
Vol 62 (3) ◽  
pp. 600-601
Author(s):  
Russell G Dent ◽  
Jack L Boese
Keyword(s):  
Plant Material ◽  
Collaborative Study ◽  
Excessive Amount ◽  
Leafy Vegetables ◽  
New Method ◽  
Official Method ◽  
Green Leafy Vegetables

Abstract The official first action method, 44.108, for the extraction of light filth from whole or chopped canned greens specifies a waterheptane flotation that results in the flotation of an excessive amount of interfering plant material and in low recoveries. A new method has been developed using a 40% isopropanol-watermineral oil flotation. The new method yielded a decreased amount of plant material and 84.9% recovery of the aphid spike compared with 42.5% recovery of the spike by the official method. The new method has been adopted as official first action to replace the existing method, except for broccoli.

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