Collaborative Study of the Photometric Molyb do vanadate Method for Phosphorus

1965 ◽  
Vol 48 (3) ◽  
pp. 654-657
Author(s):  
Mary Heckman
Keyword(s):  
Collaborative Study ◽  
Gravimetric Method ◽  
Volumetric Method ◽  
Photometric Method ◽  
Coefficients Of Variation ◽  
Standard Deviations ◽  
Official Status ◽  
Feed Samples ◽  
Phosphorus Levels ◽  
Good Agreement

Abstract Sixteen laboratories analyzed five feed samples, with phosphorus levels ranging from about 0.60 to 5.50% by the photometric molybdovanadate method studied in 1963 (This Journal, 46, 836 (1963)), and by either the volumetric method, 22.061, or the gravimetric quinoline molybdate method (ibid., 47, 170 (1964)), both of which have some official status. Eight sets of results based on the volumetric method and eight based on the gravimetric method were available. Means for all methods were in good agreement. Standard deviations and coefficients of variation were satisfactory for all methods, indicating superiority of both volumetric and gravimetric methods over the photometric method. Calculation of standard deviations for the entire range tested, however, showed the photometric method to be superior to the volumetric method and inferior to the gravimetric. The molybdovanadate method was adopted as official, first action.

Enzymatic-Ultraviolet Method for Measuring Lactose in Milk: Collaborative Study

1984 ◽  
Vol 67 (3) ◽  
pp. 637-640 ◽  
Author(s):  
David O Biltcliffe ◽  
Dick H Kleyn ◽  
J Richard Trout ◽  
◽  
D Azzara ◽  
...  
Keyword(s):  
Food Industry ◽  
Collaborative Study ◽  
Skim Milk ◽  
Gravimetric Method ◽  
T Test ◽  
Enzymatic Method ◽  
Commercial Laboratory ◽  
Aoac Method ◽  
Standard Deviations

Abstract Collaborators in 8 dairy and food industry laboratories performed one lactose determination on each of 8 unknown samples of milk, lowfat milk, or skim milk, as 3 pairs of blind duplicates. Two known samples were provided to gain experience prior to analysis of the unknown samples. All of the above samples were also analyzed for lactose content by the official AOAC gravimetric method (16.507) by a commercial laboratory. From the overall mean of results on all samples, determinations by the enzymatic method averaged 0.49% lower than by the AOAC method. This difference was significant by the t-test (P = 0.05), which indicated a lack of agreement between the compared methods in determining lactose content. Standard deviations were similar for the 3 sets of blind duplicates which ranged between 3.67 and 4.55% lactose content. F-values revealed that variations between means obtained by laboratories differed significantly as compared with variations within laboratory means. The method has been adopted official first action.

Collaborative Study of Colorimetric Methods for Phosphorus in Feeds

1964 ◽  
Vol 47 (3) ◽  
pp. 509-511
Author(s):  
Mary Heckman
Keyword(s):  
Statistical Analysis ◽  
Excellent Agreement ◽  
Phosphorus Content ◽  
Collaborative Study ◽  
Volumetric Method ◽  
Molybdenum Blue ◽  
Calcium Phosphorus ◽  
Feed Samples ◽  
Colorimetric Methods

Abstract Six feed samples of varying phosphorus content and with calcium/phosphorus ratios of 0.5— 2.0 were distributed. Eleven laboratories compared the official volumetric method (22.061) with the molybdenum blue method studied in 1962. Twelve laboratories compared 22.061 with Parks and Dunn's colorimetric molybdovanadate method now used for fertilizers. Means for all methods show excellent agreement. Statistical analysis by Youden's formula shows marked superiority of the molybdovanadate method over the molybdenum blue method.

Collaborative Study of Two New Methods for the Determination of Phosphorus in Fruits and Fruit Products

1970 ◽  
Vol 53 (3) ◽  
pp. 575-578
Author(s):  
Ben Estrin ◽  
Frederick E Boland
Keyword(s):  
Aqueous Solution ◽  
Satisfactory Agreement ◽  
Collaborative Study ◽  
Volumetric Method ◽  
Acid Solutions ◽  
Dilute Acid ◽  
New Methods ◽  
Molybdate Method ◽  
Good Agreement

Abstract A collaborative study was conducted to compare a spectrophotometric molybdovanadate method and the official gravimetric quinoline molybdate fertilizer method 2.025(b), slightly modified, with the official volumetric method 20.032. Six collaborating laboratories analyzed dilute acid solutions of the ash of 5 different kinds of fruit products and an aqueous solution containing only KH2PO4 by each of the 3 methods. Satisfactory agreement between laboratories and good agreement between methods were obtained. From the results of this collaborative study it appears that the quinoline molybdate and the molybdovanadate methods are more accurate and precise than the official volumetric method. It is recommended that both the spectrophotometric molybdovanadate method and the gravimetric quinoline molybdate method for the determination of phosphorus in fruits and fruit products be adopted as official first action.

Automation of the AOAC Photometric Phosphomolybdovanadate Method for Direct Available P2O5

1966 ◽  
Vol 49 (6) ◽  
pp. 1213-1218
Author(s):  
Charles W Gehrke ◽  
James H Baumgartner ◽  
James P Ussary
Keyword(s):  
Sampling Rate ◽  
Gravimetric Method ◽  
Photometric Method ◽  
Available Phosphorus ◽  
Automatic Method ◽  
Average Recovery ◽  
Automated Method ◽  
Relative Standard ◽  
Standard Deviations

Abstract An automatic photometric method utilizing the Technicon AutoAnalyzer has been developed to determine phosphorus in all forms of fertilizer phosphorus in the range of 2.0–4.5 mg P2O5/100 ml at a sampling rate of 40 analyses/hr. Multiple analyses of KH2PO4, 9 Magruder check samples, and numerous commercial fertilizers were made and compared with results obtained by the official quinolinium phosphomolybdate method, 2.025(b). Average range for five independent determinations was 0.22% P2O5 for the automated method and 0.26% P2O5 for the gravimetric method; average relative standard deviations were 0.44 and 0.60%, respectively. The average recovery of P2O5 from KH2PO4 was 99.8% with the photometric method and 100.3% with the quinolinium method. Results on 69 commercial fertilizers containing 5–54% P2O5 by the automatic method were only 0.02%% lower than those by the gravimetric quinolinium method. Results show that the automated phosphomolybdovanadate method for direct available phosphorus in fertilizers is accurate, precise, and less time consuming for routine control and industrial laboratories.

Collaborative Study of a Spectrofluorometric Method for Lasalocid Sodium in Feeds

1975 ◽  
Vol 58 (3) ◽  
pp. 507-512
Author(s):  
Modest Osadca ◽  
Mercedes Araujo
Keyword(s):  
Ethyl Acetate ◽  
Boric Acid ◽  
Ethyl Acetate Extract ◽  
Collaborative Study ◽  
Feed Additives ◽  
Brief Treatment ◽  
Acid Complex ◽  
Coefficients Of Variation ◽  
Spectrofluorometric Method ◽  
Feed Samples

Abstract A collaborative study has been completed on a spectrofluorometric method for determining lasalocid sodium in finished poultry feeds. After a brief treatment of feed samples with pH 4.7 buffer, the drug is extracted with ethyl acetate. The ethyl acetate extract is further cleaned up by treatment with HCI and NaOH and quantitatively measured by spectrofluorometry. Nonspecific fluorescence is corrected for via the lasalocid-boric acid complex. The method is rapid, sensitive, and free of interference. A number of other feed additives, including monensin and ethoxyquin, do not interfere. Nine collaborators participated in the study and agreement between laboratories was satisfactory. The average recoveries of lasalocid sodium from the mash feeds added at levels of 0.0064, 0.0080, and 0.0096% were 100, 98, and 99%, respectively, and the corresponding coefficients of variation were 12.8, 8.2, and 8.0% (all results included). The method has been adopted as official first action.

scholarly journals Determination of Total Dietary Fiber in Selected Foods Containing Resistant Maltodextrin by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study

2002 ◽  
Vol 85 (2) ◽  
pp. 435-444 ◽  
Author(s):  
Dennis T Gordon ◽  
Kazuhiro Okuma ◽  
J W DeVries ◽  
K Fukuhara ◽  
W Jacob ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Dietary Fiber ◽  
Average Molecular Weight ◽  
Collaborative Study ◽  
Gravimetric Method ◽  
Soluble Dietary Fiber ◽  
Total Dietary Fiber ◽  
Resistant Maltodextrin ◽  
Standard Deviations

Abstract A method was developed for determination of total dietary fiber (TDF) in foods containing resistant maltodextrin (RMD) which includes nondigestible carbohydrates that are not fully recovered as dietary fiber by conventional TDF methods such as AOAC 985.29 or 991.43. Because the average molecular weight (MW) of RMD is 2000 daltons, lower MW soluble dietary fiber components do not precipitate in 78% ethanol; therefore, RMD is not completely quantitated as dietary fiber by current AOAC methods. The accuracy and precision of the method was evaluated through an AOAC collaborative study. Ten laboratories participated and assayed 12 test portions (6 blind duplicates) containing RMD. The 6 test pairs ranged from 1.5 to 100% RMD. The method consisted of the following steps: (1) The insoluble dietary fiber (IDF) and high MW soluble dietary fiber (HMWSDF) were determined by AOAC 985.29. (2) Ion exchange resins were used to remove salts and proteins contained in the AOAC 985.29 filtrates (including ethanol and acetone). (3) The amount of low MWRMD (LMWRMD) in the filtrates were determined by liquid chromatography. (4) The TDF was calculated by summation of the IDF, HMWSDF, and LMWRMD fractions having nondigestible carbohydrates with a degree of polymerization of 3 and higher. Repeatability standard deviations (RSDr) were 1.33–7.46%, calculated by including outliers, and 1.33–6.10%, calculated by not including outliers. Reproducibility standard deviations (RSDR) were 2.48–9.39%, calculated by including outliers, and 1.79–9.39%, calculated by not including outliers. This method is recommended for adoption as Official First Action.

Collaborative Study of the Determination of Dichlorophene in Veterinary Preparations by Ultraviolet Spectrophotometry

1972 ◽  
Vol 55 (1) ◽  
pp. 163-165
Author(s):  
Dalia M Gilvydis
Keyword(s):  
Standard Deviation ◽  
Collaborative Study ◽  
Liquid Extraction ◽  
Synthetic Mixture ◽  
Ultraviolet Spectrophotometry ◽  
Average Recovery ◽  
Liquid Liquid Extraction ◽  
Coefficients Of Variation ◽  
Standard Deviations

Abstract Dichlorophene is determined in veterinary preparations by a liquid-liquid extraction and UV quantitation. Eight collaborators each analyzed 4 commercial preparations and one synthetic mixture. The average recovery for dichlorophene in the synthetic mixture is 100.3% with a standard deviation of 2.13. The standard deviations obtained for the 5 samples range from 0.13 to 3.69 with coefficients of variation from 0.69 to 3.43. It is recommended that the method be adopted as official first action.

scholarly journals Evaluation of three methods for hemoglobin measurement in a blood donor setting

1999 ◽  
Vol 117 (3) ◽  
pp. 108-112 ◽  
Author(s):  
Jacob Rosenblit ◽  
Cláudia Regina Abreu ◽  
Leonel Nulman Szterling ◽  
José Mauro Kutner ◽  
Nelson Hamerschlak ◽  
...  
Keyword(s):  
Albert Einstein ◽  
Photometric Method ◽  
Private Institution ◽  
Blood Samples ◽  
Photometric Detection ◽  
Coefficients Of Variation ◽  
The Mean ◽  
Mean Differences ◽  
Good Agreement

CONTEXT: The hemoglobin (Hb) level is the most-used parameter for screening blood donors for the presence of anemia, one of the most-used methods for measuring Hb levels is based on photometric detection of cyanmetahemoglobin, as an alternative to this technology, HemoCue has developed a photometric method based on the determination of azide metahemoglobin. OBJECTIVE: To evaluate the performance of three methods for hemoglobin (Hb) determination in a blood bank setting. DESIGN: Prospective study utilizing blood samples to compare methods for Hb determination. SETTING: Hemotherapy Service of the Hospital Israelita Albert Einstein, a private institution in the tertiary health care system. SAMPLE: Serial blood samples were collected from 259 individuals during the period from March to June 1996. MAIN MEASUREMENTS: Test performances and their comparisons were assessed by the analysis of coefficients of variation (CV), linear regression and mean differences. RESULTS: The CV for the three methods were: Coulter 0.68%, Cobas 0.82% and HemoCue 0.69%. There was no difference between the mean Hb determination for the three methods (p>0.05). The Coulter and Cobas methods showed the best agreement and the HemoCue method gave a lower Hb determination when compared to both the Coulter and Cobas methods. However, pairs of methods involving the HemoCue seem to have narrower limits of agreement (± 0.78 and ± 1.02) than the Coulter and Cobas combination (± 1.13). CONCLUSION: The three methods provide good agreement for hemoglobin determination.

scholarly journals Determination of Total Dietary Fiber (CODEX Definition) by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study

2010 ◽  
Vol 93 (1) ◽  
pp. 221-233 ◽  
Author(s):  
Barry V McCleary ◽  
Jonathan W De Vries ◽  
Jeanne I Rader ◽  
Gerald Cohen ◽  
Leon Prosky ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dietary Fiber ◽  
Resistant Starch ◽  
Collaborative Study ◽  
Gravimetric Method ◽  
Low Molecular Weight ◽  
Total Dietary Fiber ◽  
Aoac Method ◽  
Standard Deviations

Abstract A method for the determination of total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC Official MethodsSM 985.29, 991.43, 2001.03, and 2002.02, the method quantitates high- and low-molecular-weight dietary fiber (HMWDF and LMWDF, respectively). In 2007, McCleary described a method of extended enzymatic digestion at 37C to simulate human intestinal digestion followed by gravimetric isolation and quantitation of HMWDF and the use of LC to quantitate low-molecular-weight soluble dietary fiber (LMWSDF). The method thus quantitates the complete range of dietary fiber components from resistant starch (by utilizing the digestion conditions of AOAC Method 2002.02) to digestion resistant oligosaccharides (by incorporating the deionization and LC procedures of AOAC Method 2001.03). The method was evaluated through an AOAC collaborative study. Eighteen laboratories participated with 16 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of traditional dietary fiber, resistant starch, and nondigestible oligosaccharides. The dietary fiber content of the eight test pairs ranged from 11.57 to 47.83. Digestion of samples under the conditions of AOAC Method 2002.02 followed by the isolation and gravimetric procedures of AOAC Methods 985.29 and 991.43 results in quantitation of HMWDF. The filtrate from the quantitation of HMWDF is concentrated, deionized, concentrated again, and analyzed by LC to determine the LMWSDF, i.e., all nondigestible oligosaccharides of degree of polymerization 3. TDF is calculated as the sum of HMWDF and LMWSDF. Repeatability standard deviations (sr) ranged from 0.41 to 1.43, and reproducibility standard deviations (sR) ranged from 1.18 to 5.44. These results are comparable to other official dietary fiber methods, and the method is recommended for adoption as Official First Action.

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.

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