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.

Spectrofluorometric Determination of Lasalocid Sodium in Finished Feeds and Premixes

1974 ◽  
Vol 57 (3) ◽  
pp. 636-641
Author(s):  
Modest Osadca ◽  
Mercedes Araujo
Keyword(s):  
Standard Deviation ◽  
Ethyl Acetate ◽  
Boric Acid ◽  
Chemical Method ◽  
Sodium Concentration ◽  
Acid Complex ◽  
Average Recovery ◽  
Spectrofluorometric Determination ◽  
Coefficients Of Variation

Abstract A simple, rapid, and sensitive chemical method is described for determining lasalocid sodium in finished poultry feeds and premixes. The drug is extracted with ethyl acetate directly from premixes and after a brief treatment with pH 4.7 buffer from finished feeds. Lasalocid sodium concentration is measured spectrofluorometrically and a correction for nonspecific fluorescence is determined after formation of a lasalocid- boric acid complex. Replicate assays of typical poultry mashes and pellets containing about 0.0075% lasalocid sodium yielded coefficients of variation of 2.8 to 5.0%. Average recovery of lasalocid sodium added in the laboratory at 0.0037, 0.0075, and 0.0112% was 90% with a pooled standard deviation of ±1.86%.

scholarly journals Determination of Sulfamethazine in Swine and Cattle Feed by Reversed-Phase Liquid Chromatography with Post-Column Derivatization: Pre-Collaborative Study

2000 ◽  
Vol 83 (2) ◽  
pp. 255-259 ◽  
Author(s):  
Kendrick Albert ◽  
Robert L Smallidge
Keyword(s):  
Collaborative Study ◽  
Extraction Procedure ◽  
Internal Standard ◽  
Reversed Phase ◽  
Feed Additives ◽  
Official Method ◽  
Cattle Feed ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract In-house validation of a liquid chromatographic method for determination of sulfamethazine in swine and cattle feed was performed to verify that the method was ready for collaborative study under AOAC INTERNATIONAL guidelines. In this method, sulfamerazine is added during the extraction procedure and is used as an internal standard to correct for variable recovery of sulfamethazine from a variety of swine and cattle feed matrixes. The determinative step involves the use of post-column derivatization with dimethylaminobenzaldehyde which reacts with the primary amine group on the sulfonamides. Detection is at 450 nm, a wavelength at which most co-extracted matrix materials and other feed additives do not absorb light. The results indicate that the method recovery, precision, and ruggedness meet normal criteria to be ready for a collaborative study. Fortification experiments over a range of sulfamethazine concentrations from 0.006 to 0.26% showed an overall recovery relative to the internal standard of 100 ± 2%. These studies include both swine and cattle feed matrixes. The mean recovery in the analysis of 3 beef cattle experimental feeds was 98.9%. The method results agreed with the AOAC INTERNATIONAL Official Method for colorimetric analysis of swine feed. Method precision was excellent during in-house validation studies, with coefficients of variation (CVs) ranging from about 0.5 to 3%. The method ruggedness was verified with an overall CV of 3.5%.

Spectrophotometric Determination of Cyclamate in Foods: NMKL Collaborative Study

1987 ◽  
Vol 70 (3) ◽  
pp. 588-590
Author(s):  
Anna-Maija K Sjoberg ◽  
Timo A Alanko
Keyword(s):  
Aqueous Solution ◽  
Ethyl Acetate ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Soft Drinks ◽  
Uv Absorption ◽  
Acidic Aqueous Solution ◽  
Coefficients Of Variation

Abstract A spectrophotometric method for the determination of cyclamate was collaboratively studied in 9 laboratories. Ethyl acetate is added to extract cyclamate from acidic aqueous solution into water, and the cyclamate is then quantitatively converted to /V,./V-dichlorocyclohexylamine by adding excess hypochlorite. A',A'-Dichlorocyclohexylamine is determined by measuring its UV absorption at 314 nm. Six samples, 3 soft drinks with cyclamate levels of 0.36-0.47 g/kg and 3 jams with levels of 1.23-1.50 g/kg, were included in the study. Average recoveries of cyclamate were 99.7% in the soft drinks and 103.8% in the jams. Reproducibility coefficients of variation were 6.7% for the soft drinks and 4.4% for the jams.

Collaborative Study of the Determination of Sorbic Acid in Wine

1975 ◽  
Vol 58 (1) ◽  
pp. 133-135
Author(s):  
Arthur Caputi ◽  
Karen Slinkard
Keyword(s):  
Sorbic Acid ◽  
Collaborative Study ◽  
Thiobarbituric Acid ◽  
The Other ◽  
Ultraviolet Spectrophotometry ◽  
Acid Complex ◽  
Average Recovery ◽  
Colorimetric Measurement ◽  
Coefficients Of Variation

Abstract Eleven collaborators participated in a study of 2 methods for determining sorbic acid in wine. One method utilizes ultraviolet spectrophotometry and the other depends on the colorimetric measurement of a thiobarbituric acid complex. Three different wine types were each spiked with 200, 300, and 400 mg sorbic acid/ L. Average recovery ranged from 97.3 to 107.5% with the thiobarbituric acid method with coefficients of variation from 4.4 to 8.7%. The ultraviolet method gave recoveries from 97 to 103.5% with coefficients of variation ranging from 2.0 to 6.4%. Comments on both methods from collaborators were favorable. Both methods have been adopted as official first action.

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.

Preliminary Collaborative Study of Modified Spectrophotometric Determination of Pyrantel Tartrate in Swine Feeds by the Method of Standard Additions

1977 ◽  
Vol 60 (5) ◽  
pp. 1051-1053
Author(s):  
Mark A Litchman
Keyword(s):  
Phase Separation ◽  
Collaborative Study ◽  
Small Scale ◽  
Complete Dissolution ◽  
Coefficients Of Variation ◽  
Standard Additions ◽  
The Mean ◽  
Feed Samples ◽  
Pyrantel Tartrate

Abstract A modified spectrophotometric method for determining pyrantel tartrate in swine feeds was subjected to a preliminary collaborative study. Two small-scale commercial pyrantel-medicated feed samples (0.0881 and 0.0106%) were assayed in replicate by 4 collaborators. The mean results of all laboratories were 0.0862 and 0.0112%. The mean coefficients of variation were 10.57 and 6.48%, respectively. Suggestions for improving recovery include the following: complete dissolution of standard, use of analytical grade KI, careful phase separation, thorough mixing, and minimum exposure of compound to light.

High Performance Liquid Chromatographic Method for Determination of Temephos in Technical and Formulated Products: Collaborative Study

1982 ◽  
Vol 65 (3) ◽  
pp. 580-583
Author(s):  
James W Miles ◽  
Dwight L Mount
Keyword(s):  
Ethyl Acetate ◽  
High Performance ◽  
Collaborative Study ◽  
Internal Standard ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Water Dispersible ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic

Abstract An HPLC method for the determination of temephos in temephos technical and formulated products has been subjected to an international collaborative study with 14 laboratories participating. Samples were extracted with ethyl acetate and eluted on a silica gel column with ethyl acetate-hexane (1 + 9); p-nitrophenyl p-nitrobenzoate served as the internal standard. Collaborators were furnished samples of technical, 20 and 50% emulsifiable concentrates, 50% water-dispersible powder, and 1% sand granules. The coefficients of variation of the values obtained on the 5 samples were 1.21,2.02,1.26,1.89, and 9.90%, respectively. The method has been adopted official first action.

Collaborative Study of Methods for Determination of Ronnel in Feeds and Mineral Mixtures

1970 ◽  
Vol 53 (3) ◽  
pp. 634-638
Author(s):  
Albert J Gehrt
Keyword(s):  
Electron Capture ◽  
Collaborative Study ◽  
Electron Capture Detector ◽  
Binding Effect ◽  
Flame Ionization ◽  
Coefficients Of Variation ◽  
Cattle Feeds ◽  
Mineral Mixtures ◽  
Feed Samples

Abstract A GLC method (electron capture detector) for ronnel in cattle feeds at the 0.040% level and a UV method for ronnel in mineral mixtures (1–40% ronnel) were studied by 9 collaborators. Ronnel is extracted from feed by shaking with acetone, followed by direct GLC measurement. The method is simple and rapid and the electron capture detector is much more sensitive and gives cleaner ronnel measurements than the flame ionization detector used last year. Agreement between laboratories was good; coefficients of variation were 7.7, 7.1, 11.1% with ronnel recoveries of 95–100%. Analyses of feed samples after storage (several months) showed decreases in ronnel, found to be due to partial ronnel binding. Ronnel is extracted from minerals with methanol, followed by UV measurement. The coefficient of variation was 5.4%. The Associate Referee recommends that the mineral method be adopted as official final action and that the feed method be continued as official first action for 1 more year. An investigation of the binding effect is continuing.

High Pressure Liquid Chromatographic Method for Indole in Shrimp: Development of Method and Collaborative Study

1981 ◽  
Vol 64 (3) ◽  
pp. 592-602 ◽  
Author(s):  
Theodore L Chambers ◽  
Walter F Staruszkiewicz ◽  
◽  
G Bohm ◽  
J F Bond ◽  
...  
Keyword(s):  
High Pressure ◽  
Collaborative Study ◽  
Internal Standard ◽  
Peak Height ◽  
Hplc Method ◽  
Fluorescence Detector ◽  
High Pressure Liquid Chromatographic ◽  
Coefficients Of Variation ◽  
Spectrofluorometric Method ◽  
Liquid Chromatographic

Abstract A collaborative study on the determination of indole in shrimp was conducted in which a high pressure liquid chromatographic (HPLC) method and a spectrofluorometric method were compared with the AOAC gas-liquid chromatographic (GLC) method (18.075–18.078,13th ed.). In the HPLC method, 10 g shrimp was blended with methanol, an internal standard was added, and the extract was filtered. Indole was separated on an octadecylsilane reverse phase column, using 60% MeOH-H2O, and quantitated with a fluorescence detector (excitation 280 nm, emission 330 nm) by comparing the indole peak height with that of an internal standard, 2-methylindole. Recoveries at a 25 μg/100 g level averaged 104% with a range of 90–127%, and at a level of 35 μg/100 g averaged 102% with a range of 93–112%. In the spectrofluorometric method, 25 g shrimp was extracted with 2% EtOAc-hexane. After several washes, indole was partitioned into a saturated NaCl-MeOH solution and its fluorescence was measured (excitation 280 nm, emission 332 nm). Recoveries at a 25 μg/100 g level averaged 93% with a range of 0–255% and at a level of 35 μg/100 g averaged 64% with a range of 0–107%. Recoveries obtained by the AOAC-GLC method at a level of 25 μg/100 g averaged 96% with a range of 81–116% and at a level of 35 μg/100 g averaged 101% with a range of 81–119%. The coefficients of variation were 20,10, and 64% at a 25 μg/100 g level for the GLC method, the HPLC method, and the spectrofluorometric method, respectively. The HPLC method was adopted as official first action for indole levels in shrimp exceeding 1 μg/100 g.

Ion-Pair Reverse-Phase Liquid Chromatographic Determination Of Amprolium In Complete Feeds And Premixes

1988 ◽  
Vol 71 (2) ◽  
pp. 251-255
Author(s):  
Elzbieta J Kentzer ◽  
Layna S Cottingham ◽  
Robert L Smallidge
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Standard Addition ◽  
Chromatographic Determination ◽  
Ion Pair ◽  
Feed Additives ◽  
Poultry Feed ◽  
Coefficients Of Variation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Amprolium is extracted with methanol-water (2 + 1) containing 5mM dioctylsulfosuccinate (DOSS) and lOmM CaCl2. The analyte is separated from coextracted materials by isocratic ion-pair reversephase liquid chromatography, following removal of late-eluting materials on an acid alumina cleanup column, and is detected at 270 nm. The mobile phase contains 4mM DOSS with 0.3% diethylamine and 1% acetic acid in 40% acetonitrile. Linearity is satisfactory over the range of 2.5-50 /xg/mL. Mean recovery, as determined by standard addition to commercial samples, is 100.1%. Accuracy was further tested in studies comparing the LC method to the official AOAC colorimetric method, using commercial samples, and was found to be satisfactory. Studies show that common poultry feed additives, grass meals, and some pelletization aids do not interfere with the analysis; however, when bentonite is present, recovery is decreased. The precision of the method, measured over several experiments on commercial samples, is satisfactory as indicated by coefficients of variation ranging from 1 to 4.5. A ruggedness test resulted in an overall CV of 3.2%, indicating the probable success of the method in a collaborative study.

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