scholarly journals Determination of Choline in Milk and Infant Formulas by Enzymatic Analysis: Collaborative Study

2000 ◽  
Vol 83 (1) ◽  
pp. 131-138 ◽  
Author(s):  
David C Woollard ◽  
Harvey E Indyk
Keyword(s):  
Acid Hydrolysis ◽  
Infant Formula ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Analytical Techniques ◽  
Choline Oxidase ◽  
Infant Formulas ◽  
Enzymatic Analysis ◽  
Data Screening

Abstract A collaborative study was conducted on a coupled enzymatic–spectrophotometric method for the determination of choline in infant formula and milk powders. Twenty-nine laboratories participated in the analysis of 8 blind duplicates over the range of 45–175 mg/100 g sample. After the combined acid hydrolysis–phospholipase release of choline, incubation with choline oxidase in the presence of peroxidase and phenol generates a quinoneimine chromophore with 4-aminoantipyrine. Following raw data screening, overall mean RSDR was estimated at 5.14% (range, 4.26–6.34%) with a HORRAT value of 0.91 (range, 0.76–1.00) and an overall mean RSDr:RSDR value of 0.53 (range, 0.42–0.74). The method was also compared with alternative independent analytical techniques for several of the collaborative study samples.

Inductively Coupled Plasma Emission Spectroscopic Determination of Nine Elements in Infant Formula: Collaborative Study

1984 ◽  
Vol 67 (5) ◽  
pp. 985-992 ◽  
Author(s):  
Ronald F Suddendorf ◽  
Kathleen K Cook
Keyword(s):  
Infant Formula ◽  
Inductively Coupled Plasma ◽  
Emission Spectroscopy ◽  
Collaborative Study ◽  
Plasma Emission ◽  
Infant Formulas ◽  
Inductively Coupled ◽  
Coefficients Of Variation ◽  
Plasma Emission Spectroscopy

Abstract Results from a collaborative study of a method for the determination of 9 elements in infant formula, using inductively coupled plasma emission spectroscopy, are reported. Six collaborators analyzed 6 infant formulas for native and spiked levels of Ca, Cu, Fe, Mg, Mn, P, K, Na, and Zn. The within-laboratory and between-laboratory coefficients of variation were generally (69 of 108 samples) below 9% for all elements determined in all samples. Most of the average recoveries of the elements from spiked samples ranged from 90 to 105%. The method has been adopted official first action for determining Ca, Cu, Fe, Mg, Mn, P, K, Na, and Zn in infant formula.

Optimisation of microwave-assisted acid hydrolysis for the determination of seleno-amino acids bound to proteins in powdered milk, lyophilized milk and infant formula

2019 ◽  
Vol 79 ◽  
pp. 128-133
Author(s):  
Romina Lopez ◽  
Luis Escudero ◽  
Roberto D’Amato ◽  
Daniela Businelli ◽  
Massimo Trabalza-Marinucci ◽  
...  
Keyword(s):  
Amino Acids ◽  
Acid Hydrolysis ◽  
Infant Formula ◽  
Powdered Milk ◽  
Microwave Assisted

Collaborative Study of the Spectrophotometric Determination of Procainamide Hydrochloride

1976 ◽  
Vol 59 (4) ◽  
pp. 807-810
Author(s):  
Jeffrey C Hamm
Keyword(s):  
Sodium Hydroxide ◽  
Acid Medium ◽  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Dosage Forms ◽  
Standard Deviations

Abstract The USP analysis for procainamide HCl is titrimetric and relatively nonspecific, capsule and tablet dyes may interfere, and the method is not applicable to coated tablets. In the spectrophotofluorometric method the sample deteriorates when exposed to a xenon source. In the ultraviolet spectrophotometric method reported here, the sample is dispersed in acid medium, possible interferences are extracted in chloroform, base is added, procainamide is extracted in chloroform, the residue is dissolved in sodium hydroxide, and the compound is measured by absorption at 272 nm and comparison with a standard. Recoveries of standards added to capsule, tablet, and injection composites ranged from 99.3 to 102%. Twelve collaborators reported duplicate assay results for all 3 dosage forms with per cent standard deviations for 5 samples ranging from 1.01 to 1.27%. The method has been adopted as official first action.

Gas Chromatographic-Thermal Energy Analysis Method for Determination of Volatile N-Nitrosamines in Baby Bottle Rubber Nipples: Collaborative Study

1987 ◽  
Vol 70 (1) ◽  
pp. 64-68 ◽  
Author(s):  
J Ian Gray ◽  
Michael A Stachiw
Keyword(s):  
Thermal Energy ◽  
Energy Analysis ◽  
Collaborative Study ◽  
Internal Standard ◽  
Analytical Techniques ◽  
The United States ◽  
Baby Bottle ◽  
Relative Standard ◽  
Better Than

Abstract A collaborative study was conducted on the U.S. Food and Drug Administration (FDA) dichloromethane extraction method for determining volatile N-nitrosamines in baby bottle rubber nipples. Following dichloromethane extraction, A'-nitrosamines were determined by gas chromatography-thermal energy analysis. Six pairs of blind duplicate rubber nipple samples representing 6 lots were analyzed by 11 collaborating laboratories. All samples were portions taken from equilibrated composites of cut-up rubber nipples obtained from manufacturers in the United States. Recoveries of the internal standard (N-nitrosodipropylamine) at approximately 20 ppb ranged from 10 to 120%. Reproducibility relative standard deviations (RSDJ were between 35 and 45% for N-nitrosamine levels from 10 to 20 ppb. However, when data from laboratories with recoveries less than 75% were excluded (this is now specified in the method), RSD„ values were between 11 and 32% for N-nitrosamine levels from 6 to 26 ppb. Values were consistent with or better than those reported for other analytical techniques designed to quantitate trace contaminants at the low ppb level, e.g., afiatoxin in foods. The method has been adopted official first action for the quantitation of volatile N-nitrosamines in baby bottle rubber nipples.

Collaborative Study Using Atomic Absorption Spectrophotometry for the Determination of Copper in Alcoholic Products

1967 ◽  
Vol 50 (2) ◽  
pp. 338-339
Author(s):  
Duane H Strunk ◽  
A A Andreasen
Keyword(s):  
Atomic Absorption ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Good Precision ◽  
Absorption Method ◽  
Standard Curve ◽  
Absorption Spectrophotometry ◽  
Determination Of Copper

Abstract A collaborative study was conducted on the 'atomic absorption spectrophotometric method for measuring the concentration of copper in alcoholic products. In this method, the samples are aspirated directly into the burner of the instrument, and the absorhance values are converted to ppm copper by reference to a standard curve. Data show good precision and are comparable to those obtained by the ZDBT method. It is recommended that the atomic absorption method be adopted as official, first action.

Atomic Absorption Spectrophotometric Method for Determination of Polydimethylsiloxane Residues in Pineapple Juice: Collaborative Study

1990 ◽  
Vol 73 (5) ◽  
pp. 721-723
Author(s):  
Robert D Parker
Keyword(s):  
Nitrous Oxide ◽  
Atomic Absorption ◽  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Atomic Absorption Spectrophotometry ◽  
Pineapple Juice ◽  
Absorption Spectrophotometry ◽  
Relative Standard ◽  
Standard Deviations

Abstract An atomic absorption spectrophotometric method for determination of polydimethylsiloxane (PDMS) residues In pineapple juice was collaboratively studied by 9 laboratories. PDMS residues are extracted from pineapple Juice with 4- methyl-2-pentanone and the extracted silicone Is measured by atomic absorption spectrophotometry using a nitrous oxide/ acetylene flame. Collaborators analyzed 5 samples Including 1 blind duplicate. Reproducibility relative standard deviations (RSDR) were 13.1% at 31 ppm, 6.9% at 18 ppm, 14.8% at 7.9 ppm, and 16.1 % at 4.9 ppm PDMS. The method has been approved Interim official first action by AOAC.

scholarly journals Determination of Vitamin B12 in Fortified Bovine Milk- Based Infant Formula Powder, Fortified Soya-Based Infant Formula Powder, Vitamin Premix, and Dietary Supplements by Surface Plasmon Resonance: Collaborative Study

2011 ◽  
Vol 94 (4) ◽  
pp. 1217-1226 ◽  
Author(s):  
Pathik Vyas ◽  
Anthony A O'kane ◽  
E Ager ◽  
S Crooks ◽  
C Elliott ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Protein Binding ◽  
Vitamin B12 ◽  
Infant Formula ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Binding Protein ◽  
Collaborative Study ◽  
Wide Range

Abstract A collaborative study was conducted on an inhibition-based protein-binding assay using the Biacore Q™ biosensor instrument and the Biacore Qflex™ Kit Vitamin B12 PI. The samples studied included infant formula, cereals, premixes, vitamin tablets, dietary supplements, and baby food. The collaborative study, which involved 11 laboratories, demonstrated that the assay showed an RSDr of 1.59–27.8 and HorRat values for reproducibility of 0.34–1.89 in samples with levels ranging from ppm to ppb. The assay studied is a label-free protein binding-based assay that uses the principle of surface plasmon resonance (SPR) to measure the interaction between vitamin B12 and a specifc binding protein. A Biacore Q biosensor uses this principle to detect binding directly at the surface of a sensor chip with a hydrophilic gold-dextran surface. The instrument passes a mixture of prepared sample extract and binding protein solution across a covalently immobilized vitamin B12 chip surface, and the response is given as free-binding protein as the mixture binds to the immobilized surface. This technique uses the specifcity and robustness of the protein-ligand interaction to allow minimal sample preparation and a wide range of matrixes to be analyzed rapidly. The reagents and accessories needed to perform this assay are provided as the ready-to-use format “Qflex Kit Vitamin B12 PI.” The method is intended for routine use in the quantitative determination of vitamin B12 (as cyanocobalamin) in a wide range of food products, dietary vitamin supplements, and multivitamin premixes.

Spectrophotometric Determination of Cyclamate in Soft Drinks and Desserts: Complementary Collaborative Study

1988 ◽  
Vol 71 (6) ◽  
pp. 1212-1214
Author(s):  
Anna-Maija K SJÖBERG
Keyword(s):  
Spectrophotometric Determination ◽  
Spectrophotometric Method ◽  
Soft Drink ◽  
Collaborative Study ◽  
Soft Drinks ◽  
Food Control ◽  
Average Recovery ◽  
Relative Standard ◽  
Standard Deviations

Abstract Fifteen official food control laboratories participated in a collaborative study of a spectrophotometric method to determine cyclamate in a soft drink and a dessert at concentrations of 90-311 mg/L and 202-526 mg/kg, respectively, with blind duplicates and a blank. Average recovery from the soft drink was 97.5%, and from the dessert, 98.6%. Reproducibility relative standard deviations were 4.7-6.5% and 6.9-8.5%, respectively. The outlier percentage was 5.5%. This study complements an earlier work by leading Nordic food laboratories and was designed according to the latest recommendations. The results of this study were compared with those of the earlier collaborative study and with general collaborative results obtained by AOAC.

UV Determination of Naphthaleneacetic Acid in Apples and Potatoes

1970 ◽  
Vol 53 (1) ◽  
pp. 149-151
Author(s):  
Robert C Randall
Keyword(s):  
Spectrophotometric Method ◽  
Collaborative Study ◽  
Naphthaleneacetic Acid ◽  
Florisil Column ◽  
Average Recovery

Abstract Six collaborators studied a spectrophotometric method in which the chopped product is extracted with CHCl3, the extract is cleaned up on a Florisil column, and the residue is determined spectrophotometrically in the UV region (283 nm). The overall average recovery of the collaborative study was 93%. It is recommended that the method be adopted as official first action.

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