Separation and determination of denatured caseins by hydrophobic interaction chromatography. Part II. Method validation and applications
| Autor: | Emilia Bramanti, Giorgio Raspi, Robert E. Synovec, Chandra Sortino |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Detection limit
Chromatography food.ingredient MILK PROTEINS COWS Elution Chemistry Hydrophilic interaction chromatography Analytical chemistry Caseins Reproducibility of Results Standard solution Biochemistry Analytical Chemistry Milk food Casein Standard addition Skimmed milk Electrochemistry Animals Environmental Chemistry Quantitative analysis (chemistry) Spectroscopy |
| Zdroj: | Analyst (Lond., 1877, Online) 126 (2001): 997–1000. doi:10.1039/b102360h info:cnr-pdr/source/autori:Bramanti, E (Bramanti, E); Sortino, C (Sortino, C); Raspi, G (Raspi, G); Synovec, RE (Synovec, RE)/titolo:Separation and determination of denatured caseins by hydrophobic interaction chromatography-Part II. Method validation and applications/doi:10.1039%2Fb102360h/rivista:Analyst (Lond., 1877, Online)/anno:2001/pagina_da:997/pagina_a:1000/intervallo_pagine:997–1000/volume:126 |
| ISSN: | 1364-5528 0003-2654 |
| DOI: | 10.1039/b102360h |
| Popis: | A method recently described for the separation of denatured alpha-, beta- and kappa -caseins by hydrophobic interaction chromatography was validated by the analysis of reference skim milk powder (BCR-063R) certificated for total nitrogen content. The method is based on fast and easy solubilization of commercial and real samples by 4.0 M guanidine thiocyanate and elution on a TSK-Gel (R) Phenyl-5PW column (TosoHaas) in the presence of 8.0 M urea in the mobile phase. No preliminary precipitation or separation of the casein fraction is required. A linear relationship between the concentration of casein and peak area (UV absorbance detector at 280 nm) was obtained over the concentration range 0.5-60 muM. The detection limits for alpha-, beta- and kappa -caseins ranged between 0.30 and 0.65 muM. The precision of the method was evaluated; the relative standard deviation for alpha-, beta- and kappa -casein determination ranged between 2.2 and 2.7% for standard solutions and between 3.5 and 6.2% for real sample solutions. The mean casein content found in 10 aliquots of BCR-063R calculated with respect to the total protein content (estimated on the basis of certified total nitrogen content) was 79.1 +/- 2.7%. Results of linear fitting of standard additions data for alpha-, beta- and kappa -caseins to BCR-063R were compared with linear fitting of alpha-, beta- and kappa -casein calibration data. The method was applied to commercial caseins and to 31 real, raw samples [processed cow's milk (pasteurised, UHT-treated), follow-up milk powders, cream, cheeses, casein-free infant formulae, cookies for babies containing milk proteins] with the aim of showing the wide applicability of the method in order to determine alpha-, beta- and kappa -caseins. |
| Databáze: | OpenAIRE |
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