Colorimetric Determination of Ronidazole in Feeds

1969 ◽  
Vol 52 (1) ◽  
pp. 101-107
Author(s):  
C R Szalkowski ◽  
J Kanora
Keyword(s):  
Standard Deviation ◽  
Feed Additives ◽  
Colorimetric Determination ◽  
Aminobenzoic Acid ◽  
Colored Complex ◽  
Poultry Feeds ◽  
Naoh Solution ◽  
Significant Interference ◽  
Feed Samples

Abstract Ronidazole, (l-melhyl-5-nitroimidazoI- 2-yl)mcthyl carbamate, is extracted from finished poultry feeds with methanol and chromatographcd on an AL2O3-FIorex column. The eluate is concentrated and dissolved in CCI4 and the ronidazole is extracted with. H2O. The purified ronidazole is hydrolyzcd in NaOH solution in the presence of copper and p-aminobenzoic acid; the resulting diazonium compound is then coupled with naphthylethylenediamine to form a colored complex, which is measured spectrophotometrically at 550 mµ. No significant interference was found from finished feeds, domestic and foreign, or from 48 common feed additives. Recovery experiments on 36 laboratory-prepared feed samples at levels ranging from 0.0015 to 0.030% ronidazole averaged 100.8% with a standard deviation of 2.4.

Colorimetric Determination of Arprinocid in Feed

1978 ◽  
Vol 61 (5) ◽  
pp. 1078-1082
Author(s):  
David W Fink ◽  
Kobert P Martin ◽  
James V Pivnichny ◽  
Jung-Sook K Shim
Keyword(s):  
Standard Deviation ◽  
Reaction Time ◽  
Analytical Method ◽  
Acidic Solution ◽  
Feed Additives ◽  
Colorimetric Determination ◽  
Colorimetric Measurement ◽  
Relative Standard ◽  
Zinc Reduction

Abstract An analytical method has been developed for the determination of arprinocid (9-(2-chloro- fluorophenylmethyl) -9ff-purin-6-amine) in feed, based upon measurement of the absorbance of the diazo chromophore formed from product of zinc reduction of the drug in acidic solution. The analyte is extracted from the feed into chloroform in the presence of a pH 7 phosphate buffer and isolated by adsorption chromatography on alumina, followed by partitioning between hexane and 0.15M HC1. The reduction product in the aqueous phase is then treated for colorimetric measurement. This procedure has been applied to determining 0.0010-0.0080% arprinocid in feed with precision of <5% relative standard deviation near the middle of this concentration range. Of 32 feed additives examined, only zoalene and sulfamethazine were serious interferences. study and discussion of several factors, e.g., reaction time, pH, and amount of zinc metal, that affect the analytical reactions are also included.

Collaborative Study of the Colorimetric Determination of Sulfadimethoxine in Feeds

1970 ◽  
Vol 53 (3) ◽  
pp. 638-641
Author(s):  
M Osadca ◽  
E De Ritter
Keyword(s):  
Collaborative Study ◽  
Colorimetric Determination ◽  
Good Recovery ◽  
Drug Levels ◽  
Poultry Feeds ◽  
Extraction And Purification ◽  
Feed Samples

Abstract A method is described for determination of sulfadimethoxine in medicated poultry feeds. After extraction and purification of the extract, sulfadimethoxine is determined colorimetrically after diazotization and coupling with N-(l-naphthyl)ethylenediamine. The method was studied collaboratively by 11 laboratories on 4 feed samples containing graded drug levels. The method yields good recovery and precision and is recommended for adoption as official first action.

Determination of Buquinolate in Chicken Feeds by Thin Layer Chromatography and Fluorometry

1967 ◽  
Vol 50 (2) ◽  
pp. 264-268
Author(s):  
H Borfitz ◽  
J Para ◽  
J V Stickles ◽  
G B Ginther ◽  
B C Southworth
Keyword(s):  
Standard Deviation ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Chloroform Extract ◽  
Feed Additives ◽  
Reference Standard ◽  
Solvent Systems ◽  
Layer Chromatography ◽  
Feed Samples

Abstract A procedure has been developed for determining buquinolate (ethyl 4-hydroxy- 6,7- diisobutoxy - 3 - quinolinecarboxylate) in finished chicken feeds. In the procedure, a chloroform extract of the feed is concentrated to a small known volume, separated from background substances by thin layer chromatography on silica gel (two solvent systems), eluted from the plate, and compared fluorometrically with reference standard buquinolate. No background interference was found from 157 feed samples investigated or from 11 common feed additives. Recovery experiments on 31 samples at levels ranging from 0.0044 to 0.0143% buquinolate averaged 99.7% with a standard deviation of 3.3. The method is equally applicable to both fresh and aged feeds. This method was studied collaboratively, results were good, and the method is recommended for adoption as official, first action

Spectrophotofluorometric Estimation of Low Levels of Diethylstilbestrol in Feedstuffs

1973 ◽  
Vol 56 (6) ◽  
pp. 1483-1488
Author(s):  
Marshall T Jeffus ◽  
Charles T Kenner
Keyword(s):  
Standard Deviation ◽  
Fluorescent Intensity ◽  
Low Levels ◽  
Feed Samples

Abstract A method for the determination of low levels of diethylstilbestrol in feedstuffs is described. Interfering feed extractives are removed by using a tripotassium phosphate-Celite column prior to irradiation. The dione produced by irradiation is oxidized to a phenanthrenediol and extracted into CH2CI2 for measurement of fluorescent intensity. The amount of diethylstilbestrol found in several feed samples ranged from 0 to 10 ng (0.0–0.5 ppb) with an average of 4 ng (0.2 ppb). Recoveries of 100 ng standards (equivalent to 5 ppb) added to the same samples averaged 91 ng with a standard deviation of 14 ng. Recoveries of 1000 ng standards (equivalent to 50 ppb) added to the same samples averaged 820 ng with a standard deviation of 14 ng. For 100 ng standards analyzed beginning with the irradiation procedure, the standard deviation was 5.6%, and for 1000 ng standards, the standard deviation was 2.8%.

Application of the CEN/ISO Standard for Phytase Activity Measurements to a New Phytase Product: Determination of a Robust Conversion Factor by an Interlaboratory Study for Screening Feed Samples

2019 ◽  
Vol 102 (6) ◽  
pp. 1808-1813
Author(s):  
María José González de la Huebra ◽  
Piotr Robouch ◽  
Håkan Emteborg ◽  
Stefano Bellorini ◽  
Aneta Cizek-Stroh ◽  
...  
Keyword(s):  
Conversion Factor ◽  
Feed Additives ◽  
Phytase Activity ◽  
Feed Additive ◽  
The European Union ◽  
Iso Standard ◽  
Official Control ◽  
Activity Measurements ◽  
Feed Samples

Abstract Background: Phytase-based preparations are important feed additives currently authorised in the European Union (EU). The European Standard (EN) and International Organization for Standardization (ISO) standard 30024 describes a harmonized method for the determination of phytase activity and is fit-for-purpose for official control of a group of phytase products. However, it is not suitable for the determination of the phytase activity of a new feed additive encoded as 4a16 in the EU Register of Feed Additives, to which a slightly different phytase activity definition has been attributed. Objective: To establish a robust conversion factor to support official control laboratories that apply the EN ISO method when monitoring feed products containing 4a16. Methods: The phytase activity of test materials was determined by the participants using the EN ISO and/or the “applicant” methods. Results: Robust relative SDs for repeatability and for reproducibility of the methods applied for the determination of the phytase activity in the materials containing the 4a16 feed additive ranged from 2.6 to 22% (EN ISO method) and from 2.4 to 39% (applicant method). Conclusions: The data obtained confirmed the performance characteristics published for other phytase-based feeds in the related standard methods. These results allowed us to estimate a factor of 2.68 to convert phytase activities measured with the EN ISO method into the enzyme activity measured with the applicant method. Highlights: The obtained conversion factor will allow EU official laboratories to screen feed samples supplemented with the 4a16 phytase by applying EN ISO Standard 30024.

Application of the CEN/ISO Standard for Phytase Activity Measurements to a New Phytase Product: Determination of a Robust Conversion Factor by an Interlaboratory Study for Screening Feed Samples

2019 ◽  
Vol 102 (6) ◽  
pp. 1808-1813
Author(s):  
María José González de la Huebra ◽  
Piotr Robouch ◽  
Håkan Emteborg ◽  
Stefano Bellorini ◽  
Aneta Cizek-Stroh ◽  
...  
Keyword(s):  
Conversion Factor ◽  
Feed Additives ◽  
Phytase Activity ◽  
Feed Additive ◽  
The European Union ◽  
Iso Standard ◽  
Official Control ◽  
Activity Measurements ◽  
Feed Samples

Background: Phytase-based preparations are important feed additives currently authorised in the European Union (EU). The European Standard (EN) and International Organization for Standardization (ISO) standard 30024 describes a harmonized method for the determination of phytase activity and is fit-for-purpose for official control of a group of phytase products. However, it is not suitable for the determination of the phytase activity of a new feed additive encoded as 4a16 in the EU Register of Feed Additives, to which a slightly different phytase activity definition has been attributed. Objective: To establish a robust conversion factor to support official control laboratories that apply the EN ISO method when monitoring feed products containing 4a16. Methods: The phytase activity of test materials was determined by the participants using the EN ISO and/or the “applicant” methods. Results: Robust relative SDs for repeatability and for reproducibility of the methods applied for the determination of the phytase activity in the materials containing the 4a16 feed additive ranged from 2.6 to 22% (EN ISO method) and from 2.4 to 39% (applicant method). Conclusions: The data obtained confirmed the performance characteristics published for other phytase-based feeds in the related standard methods. These results allowed us to estimate a factor of 2.68 to convert phytase activities measured with the EN ISO method into the enzyme activity measured with the applicant method. Highlights: The obtained conversion factor will allow EU official laboratories to screen feed samples supplemented with the 4a16 phytase by applying EN ISO Standard 30024.

scholarly journals Quantitative colorimetric determination of urinary p-aminophenol with an automated analyzer

1997 ◽  
Vol 43 (4) ◽  
pp. 627-634 ◽  
Author(s):  
Jan F Van Bocxlaer ◽  
Karine M Clauwaert ◽  
Willy E Lambert ◽  
André P De Leenheer
Keyword(s):  
Colorimetric Method ◽  
Stability Study ◽  
Colorimetric Determination ◽  
Manganese Ions ◽  
Significant Interference ◽  
Related Compounds ◽  
Health Screen ◽  
Linear Concentration Range ◽  
Linear Concentration

Abstract We developed an automated colorimetric method for the quantitative determination of p-aminophenol with a Cobas Mira analyzer. The procedure can be used for the biological monitoring of human exposure to aniline. An absorbed aniline dose is extensively oxidized to p-aminophenol, which is excreted in urine mainly as glucurono- and sulfo- conjugates. After enzymatic hydrolysis, we reacted the free compound with resorcinol in the presence of manganese ions to form an indophenol dye, which is measured at 550 nm. Excellent accuracy (102.8%, 103.9%, and 96.8% at 2.5, 50, and 90 mg/L, respectively) and precision (7.7%, 2.1%, and 0.8% CV for within-run and 11.1%, 4.7%, and 4.6% for total reproducibility at 2.5, 50, and 90 mg/L, respectively) were achieved over a linear concentration range of 2.0 to 100 mg/L. The detection limit was 0.9 mg/L and no significant interference (except for o-aminophenol) was found for several investigated drugs and related compounds. The proposed method was used for a stability study and to analyze several samples from an occupational health screen.

GLC and Colorimetric Determination of Ipronidazole in Finished Feeds

1970 ◽  
Vol 53 (1) ◽  
pp. 35-39
Author(s):  
M Osadca ◽  
M Araujo ◽  
E De Ritter
Keyword(s):  
Spectrophotometric Method ◽  
Diatomaceous Earth ◽  
Complete Recovery ◽  
Feed Additives ◽  
Colorimetric Determination ◽  
Sulfa Drugs ◽  
Gas Chromatograph ◽  
Layer Chromatography ◽  
Benzene Extract

Abstract Ipronidazole at 0.003% and above in finished feeds is determined gas chromatographically and spectrophotometrically. In the GLC method, ipronidazole is extracted with warm 0.27V HC1 and an aliquot is made alkaline and extracted with benzene. A portion of the benzene extract is injected into a gas chromatograph equipped with an electron capture detector. The method is very sensitive, rapid, and reproducible and yields complete recovery of the drug. Ipronidazole is separated from dimetridazole; vitamins, antibiotics, sulfa drugs, and arsenicals do not interfere. In the spectrophotometric method the dilute HCI extract is purified on a column of magnesium oxide, diatomaceous earth, and asbestos. An aliquot of the eluate is made alkaline, ipronidazole is extracted with chloroform, and the absorbance is measured at 318 nm. Ipronidazole is then removed by evaporation at 75°C, the residue is redissolved in the same volume of chloroform, and the feed extract blank is measured. Average recovery of ipronidazole from feeds is about 98%. Other feed additives such as vitamins, antibiotics, sulfa drugs, and arsenicals do not interfere. Dimetridazole, which is also measured by the spectrophotometric method, is differentiated by thin layer chromatography.

Colorimetric Determination of 3-Amino-l,2,4-Triazole in Grain or Meal

1982 ◽  
Vol 65 (1) ◽  
pp. 24-27
Author(s):  
Michel Galoux ◽  
Jean-C Van Damme ◽  
Albert Bernes
Keyword(s):  
Sulfuric Acid ◽  
Limit Of Detection ◽  
Colorimetric Method ◽  
Colorimetric Determination ◽  
Colored Complex ◽  
Adsorption Desorption

Abstract This colorimetric method for the determination of 3-amino-l,2,4-triazole in grain or meal is a modification of the Storherr and Burke method. The herbicide is extracted from grain with methanol, and purified by adsorption-desorption on resin. The extract is cleaned by digestion with sulfuric acid and clarified with charcoal. The colored complex formed by coupling with N-(1-naphthyl)ethylenediammonium dichloride is measured spectrophotometrically at 455 nm. The limit of detection is 0.05 ppm.

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