Collaborative Study of Betaine in Orange Juice

1970 ◽  
Vol 53 (3) ◽  
pp. 568-571
Author(s):  
Grayson R Rogers
Keyword(s):  
Amino Acids ◽  
Standard Deviation ◽  
Ion Exchange ◽  
Systematic Error ◽  
Orange Juice ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Actual Data ◽  
Random Errors ◽  
Water Solutions

Abstract An ion exchange-colorimetric method for determining betaine in orange juice was studied by 11 collaborators on 4 orange juice samples and 2 synthetic water solutions consisting of sucrose, dextrose, and various amino acids found in orange juice. Average recoveries in the collaborative study were 96.7 and 95.9%. Results show that the precision standard deviation among laboratories is generally acceptable. The distribution of the actual data is greater than normally expected, but random errors appear to be responsible since no significant systematic error can be detected in the data. The method is recommended for adoption as official first action.

Collaborative Study of a Colorimetric Determination of Nitrate in Tobacco

1969 ◽  
Vol 52 (4) ◽  
pp. 756-759
Author(s):  
C James Rosene
Keyword(s):  
Sulfuric Acid ◽  
Standard Deviation ◽  
Systematic Error ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Water Soluble ◽  
Colorimetric Determination ◽  
Error Standard Deviation

Abstract A colorimetric method for determining water-soluble nitrate in tobacco was studied by 14 laboratories on eight Burley and two cigar filler tobacco samples with nitrate levels of 0.5–2.4%. In the method, ground tobacco is extracted with water and filtered, and an aliquot is then treated with 2,4-xylenol in sulfuric acid; then the resulting 6-nitro-2,4-xylenol is removed by distillation and measured spectrophotometrically at 450 µm. Results show that, althoughthe precision standard deviation among laboratories is generally acceptable, the systematic error standard deviation is unacceptably high. This study will be continued.

Collaborative Study of a Colorimetric Method for Paraquat in Formulations

1968 ◽  
Vol 51 (6) ◽  
pp. 1306-1309
Author(s):  
A A Carlstrom
Keyword(s):  
Free Radical ◽  
Standard Deviation ◽  
Systematic Error ◽  
Random Error ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Sodium Dithionite ◽  
Reference Standard ◽  
Standard Curve ◽  
Diluted Solution

Abstract A colorimetric method described by Yuen, Bagness, and Myles in 1967 was collaboratively studied with paraquat formulations containing 2 lb/gal. (about 20% cation). Paraquat is determined in a diluted solution by measuring the absorbance, at 600 mμ, of the blue free radical produced by reduction with alkaline sodium dithionite, and its absorbance is compared to a reference standard curve. Standard deviation estimation of random error was 0.22 for paraquat dimethylsulfate formulations and 0.26 for paraquat dichloride. Standard deviation estimates of systematic error were 0.20 and 0.62, respectively. The method is recommended for adoption as official, first action.

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 Modified Elmore Method for Mercury in Formulations

1971 ◽  
Vol 54 (3) ◽  
pp. 685-687
Author(s):  
James E Launer
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Random Error ◽  
Collaborative Study ◽  
Test Pair ◽  
Titrimetric Method ◽  
Mercuric Nitrate ◽  
Thiocyanate Solution ◽  
Diluted Solution ◽  
Bearing Materials

Abstract The titrimetric method for mercury described by Elmore in 1946 was modified and collaboratively studied with formulations containing 6.7% phenylmercury urea in one test pair and 1% mercuric nitrate in another test pair. Mercury is determined in diluted solution, following reflux at 30 drops/min with fuming H2SO4-red fuming HNO3, by titration with standard thiocyanate solution, using ferric alum as indicator. The method is not applicable in presence of large quantities of chlorine-bearing materials. Single determinations on 4 samples by 14 collaborators showed that the standard deviation estimation of random error was 0.058 for phenylmercury urea and 0.004 for mercuric nitrate. Standard deviation estimates of systematic error were 0.048 and 0.009, respectively. The method has been adopted as official first action.

δ18 Measurements in Water for Detection of Sugar Beet-Derived Syrups in Frozen Concentrated Orange Juice: Collaborative Study

1992 ◽  
Vol 75 (6) ◽  
pp. 1107-1111 ◽  
Author(s):  
Landis W Doner, ◽  
Allan R Brause ◽  
Donald R Petrus
Keyword(s):  
Mass Spectrometry ◽  
Standard Deviation ◽  
Stable Isotope ◽  
Sugar Beet ◽  
Orange Juice ◽  
Isotope Ratio ◽  
Collaborative Study ◽  
Isotope Ratio Mass Spectrometry ◽  
Stable Isotope Ratio ◽  
The Mean

Abstract Stable isotope ratio mass spectrometry has shown that pure frozen concentrated orange juices (FCOJ) of 63-67° brix possess a mean δ18 value of +14.28%o, with a standard deviation of 1.80. Beet invert syrups, which are produced using ground water, possess negative values. As a result, δ18 values decrease on addition of such syrups to FCOJ. Samples with values less than +8.9%o (3 standard deviations from the mean for pure FCOJs) can confidently be considered as adulterated. A collaborative study was conducted in which a pure FCOJ and 4 samples adulterated to various levels with medium beet invert syrup were sent to each of 6 collaborators. In all but 2 instances, juices containing more than 10% beet syrup would have been classified as adulterated by the collaborators; none would have classified pure juice as adulterated. The plot of mean δ18 values for all collaborators at each adulteration level has a correlation coefficient >0.999. The method has been adopted first action by AOAC International.

Collaborative Study of the Thermistor Cryoscopic Method for the Determination of the Freezing Point Value of Milk

1968 ◽  
Vol 51 (4) ◽  
pp. 816-821
Author(s):  
R W Henningson
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Freezing Point ◽  
Collaborative Study

Abstract Data from 19 collaborators for two sample pairs were used to estimate the precision and systematic error of the thermistor cryoscopic method for determining the freezing point value of milk. Precision was greater for the milks (0.0015°) than for the standards (0.004°). The systematic error was estimated to be 0.0033°. The standard deviation for interlaboratory individual determinations was estimated to be 0.0049°.

Collaborative Study of the Official AOAC Flame Photometric Method for the Determination of Sodium in Fertilizers

1972 ◽  
Vol 55 (5) ◽  
pp. 986-988
Author(s):  
Luis F Corominas
Keyword(s):  
Ion Exchange ◽  
Systematic Error ◽  
Collaborative Study ◽  
Flame Photometry ◽  
Photometric Method ◽  
Standard Deviations

Abstract The present official final action method, 2.132–2.135 (11 th Ed.), has been compared with the 10th Edition method, 2.117–2.120; the need for ion exchange cleanup before flame photometry was also studied for samples containing 0.1-0.7% sodium. In general, the 11th Edition method produced more precise results; elimination of ion exchange treatment improved values obtained for the standard deviations of the systematic error. These findings are based on 600 individual results reported by 9 laboratories for 4 samples.

Determination of Bismuth in Pharmaceutical Dosage Forms by Conventional DC Polarography

1972 ◽  
Vol 55 (1) ◽  
pp. 155-160
Author(s):  
William M Plank
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Dosage Forms ◽  
Official Method ◽  
Pharmaceutical Dosage Forms ◽  
Relative Standard ◽  
Dc Polarography

Abstract A method has been investigated for the determination of bismuth in pharmaceutical dosage forms by conventional dc polarography. The method is applicable to tablets, emulsions, suspensions, injectables, and bulk powders. A collaborative study has shown the method to be superior in accuracy and precision to the present official colorimetric method, 36.300- 36.304. The results from 16 determinations performed by 8 collaborators were: 100.0±1.5% recovery on a synthetic powder mix, a relative standard deviation of 1.9% on a commercial tablet sample, and a relative standard deviation of 2.1% on a magma sample. By comparison, the collaborative data reported for the present official method gave relative standard deviations of 3.4 and 3.2% on 2 samples of powder mixtures. It is recommended that the polarographic method be adopted as official first action.

scholarly journals Initial Feasibility and Clinical Implementation of Daily MR-guided Adaptive Head and Neck Cancer Radiotherapy on a 1.5T MR-Linac System: Prospective R-IDEAL 2a/2b Systematic Clinical Evaluation of Technical Innovation

2020 ◽  
Author(s):  
Brigid A. McDonald ◽  
Sastry Vedam ◽  
Jinzhong Yang ◽  
Jihong Wang ◽  
Pamela Castillo ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Systematic Error ◽  
Organs At Risk ◽  
Pass Rate ◽  
Random Errors ◽  
Clinical Implementation ◽  
Adaptive Treatment ◽  
Treatment Plans ◽  
On Line ◽  
The Impact

AbstractIntroductionThis prospective study is the first report of daily adaptive radiotherapy (ART) for head & neck cancers (HNC) using a 1.5T MR-linac, with particular focus on safety & feasibility and dosimetric results of an on-line rigid registration-based adapt-to-position (ATP) workflow.MethodsTen HNC patients received daily ART on a 1.5T/7MV MR-linac, six using ATP only and four using ATP with one off-line adapt-to-shape re-plan. Setup variability with custom immobilization masks was assessed by calculating the average systematic error (M), standard deviation of the systematic error (∑), and standard deviation of the random error (σ) of the isocenter shifts. Quality assurance was performed with a cylindrical diode array using 3%/3mm γ criteria. Adaptive treatment plans were summed for each patient to compare delivered dose with planned dose from the reference plan. The impact of dosimetric variability between adaptive fractions on the summation plan doses was assessed by tracking the number of optimization constraint violations at each individual fraction.ResultsThe random errors (mm) for the x, y, and z isocenter shifts, respectively, were M = − 0.3, 0.7, 0.1; ∑ = 3.3, 2.6, 1.4; and σ = 1.7, 2.9, 1.0. The median γ pass rate was 99.9% (range: 90.9%-100%). The differences between the reference and summation plan doses were within [-0.61%, 1.78%] for the CTV and [-11.74%, 8.11%] for organs at risk (OARs), though percent increases in OAR dose above 2% only occurred in three cases, each for a single OAR. All cases had at least two fractions with one or more constraint violations. However, in nearly all instances, constraints were still met in the summation plan despite multiple single-fraction violations.ConclusionDaily ART on a 1.5T MR-linac using an on-line ATP workflow is safe and clinically feasible for HNC and results in delivered doses consistent with planned doses.

Collaborative Study and Ion Exchange Method for the Determination of Methyldopa, Chlorothiazide, and Hydrochlorothiazide in Drug Mixtures

1971 ◽  
Vol 54 (3) ◽  
pp. 603-608
Author(s):  
Rod Chu
Keyword(s):  
Standard Deviation ◽  
Ion Exchange ◽  
Exchange Resin ◽  
Collaborative Study ◽  
Cation Exchange Resin ◽  
Resin Column ◽  
Exchange Method ◽  
Average Recovery ◽  
Ion Exchange Method

Abstract A method for the assay of methyldopa with either chlorothiazide or hydrochlorothiazide was studied collaboratively by 8 laboratories. The method involves the use of AG50-4X, 100-200 mesh H+ cation exchange resin to resolve the compounds. The thiazides pass freely through the resin column, while methyldopa is retained and subsequently eluted with 1N methanolic HCl. The components are quantitatively measured by spectrophotometry at 280 (methyldopa), 277 (chlorothiazide), and 270 nm (hydrochlorothiazide). For the methyldopa-chlorothiazide combination, the overall average recovery for methyldopa was 98.5% with a standard deviation of 2.50; and for the methyldopa-hydrochlorothiazide combination, 96.4% with a standard deviation of 2.30. The average recoveries for chlorothiazide and hydrochlorothiazide were 99.6 (standard deviation of 1.14) and 98.8% (standard deviation of 2.92), respectively. The method has been adopted as official first action for the determination of methyldopa and chlorothiazide in combination.

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