Resumo (PT):
The present paper reports the development and validation of an analytical micro-method for tocopherols quantification in espresso coffee by normal-phase HPLC with fluorescence detection. The proposed method consists in a liquid–liquid extraction with n-hexane:ethyl acetate, followed by a clean-up with dimethylformamide to eliminate co-eluting interferences. The method showed good intra- and inter-day precisions (coefficient of variation < 6.5%), good accuracies (98 ± 6%), and high correlation coefficients (r > 0.999) for standards subjected to the entire procedure. Only α- and β-tocopherols were identified in the brews. The detection and quantification limits were 0.5 and 1.4 ng/ml, for α-tocopherol, and 0.4 and 1.1 ng/ml, for β-tocopherol, respectively. A mean total tocopherol content (α + β) of 3.5 ± 0.9 μg in commercial espresso coffee blends (30 ml) was detected. The proposed method requires low solvent consumption and proved to be sensitive, precise and accurate.
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Keywords: Espresso coffee; Coffee brew; Tocopherols; Vitamin E; HPLC
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<a target="_blank" href=" http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T6R-4VH8B3V-1&_user=2460038&_coverDate=08%2F15%2F2009&_rdoc=57&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info(%23toc%235037%232009%23998849995%231009083%23FLA%23display%23Volume)&_cdi=5037&_sort=d&_docanchor=&_ct=63&_acct=C000057398&_version=1&_urlVersion=0&_userid=2460038&md5=c70920bfcff820ffa4dcbe726b30974e&searchtype=a"> Texto integral</a>
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Abstract (EN):
The present paper reports the development and validation of an analytical micro-method for tocopherols quantification in espresso coffee by normal-phase HPLC with fluorescence detection. The proposed method consists in a liquid–liquid extraction with n-hexane:ethyl acetate, followed by a clean-up with dimethylformamide to eliminate co-eluting interferences. The method showed good intra- and inter-day precisions (coefficient of variation < 6.5%), good accuracies (98 ± 6%), and high correlation coefficients (r > 0.999) for standards subjected to the entire procedure. Only α- and β-tocopherols were identified in the brews. The detection and quantification limits were 0.5 and 1.4 ng/ml, for α-tocopherol, and 0.4 and 1.1 ng/ml, for β-tocopherol, respectively. A mean total tocopherol content (α + β) of 3.5 ± 0.9 μg in commercial espresso coffee blends (30 ml) was detected. The proposed method requires low solvent consumption and proved to be sensitive, precise and accurate.
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Keywords: Espresso coffee; Coffee brew; Tocopherols; Vitamin E; HPLC
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<a target="_blank" href=" http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T6R-4VH8B3V-1&_user=2460038&_coverDate=08%2F15%2F2009&_rdoc=57&_fmt=high&_orig=browse&_origin=browse&_zone=rslt_list_item&_srch=doc-info(%23toc%235037%232009%23998849995%231009083%23FLA%23display%23Volume)&_cdi=5037&_sort=d&_docanchor=&_ct=63&_acct=C000057398&_version=1&_urlVersion=0&_userid=2460038&md5=c70920bfcff820ffa4dcbe726b30974e&searchtype=a"> Full text</a>
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Idioma:
Inglês
Tipo (Avaliação Docente):
Científica