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Register a new userDetermination of Caffeine and Theobromine in Six different Brands of Tea Infused by Different Methods Using HPLC Method
تعيين الكافئين و التيوبرومين في ستة أنواع من مشروب الشاي المنقوع بطرائق مختلفة بطريقة الكروماتوغرافية السائلة العالية الأداء
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Damascus University ورقة بحثية
Publication date
2011
fields
Chemistry
and research's language is
العربية
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Shamra Editor
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جرى في هذا البحث تطوير طريقة تحليل لتعيين الكافئين و التيوبرومين كيفاً و كماً بالاعتماد علـى تقانة الكروماتوغرافية السائلة عالية الأداء، و ذلك في عينات مختلفة من مشروب الشاي الأسود و الأخضر المحضرة بطرائق نقع مختلفة، كالنقع مع غليان و النقع دون غليان و النقع المتكـرر و النقـع المـستمر. استخدم طور متحرك من مزيج من الميتانول و الماء الثنائي التقطير بنسبة حجمية (40:60) ، وفق شروط العمل، كان زمن الاستبقاء للتيوبرومين ثلاث دقائق و للكافئين خمس دقائق.
This paper presents a developed HPLC method for the determination of caffeine and theobromine in different black and green tea infusion samples, using different infusion methods, such as infusion with and without boiling, repeated and continuous infusion. A mixture of double-distilled water and methanol (60:40 v/v), was used as a mobile phase. In this condition, the retention time for theobromine was three minutes and for caffeine five minutes.
References used
Yamamoto, T. Juneja, L. Chu, D. and Kim, M. (1997). Chemistry and Applications of Green Tea. CRC Press, Boca Raton, New York. ISPN 0-84, 3- 4006-3, 4
Engelhardt, U. (2010). Chemistry of Tea. Comprehensive Natural Products II, V. 3, pp. 999-1032
Ody, P., Complete Guide to Medicinal Herbs. Dorling Kindersley Publishing. New York, 48. ISBN 0-7894-6785-2
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Four different brands of black tea and one brand of green tea commonly
available in Syrain markets were tested to measure the level of fluoride
contained in their liquid using four different methods of infusion and utilizing
the spectrophotometer
technology: A. Infusion without boiling. B. Infusion with
boiling. C. Repeated infusion. D. Continuous infusion.
The results have indicated that the average level of fluoride in the samples
of black tea liquid is higher than the one in the green tea sample regardless of
the infusion method used. Also, it was found that the level of fluoride released
from all samples is higher when boiling them in water from 1 to 5 minutes. In
addition, it was proved that the level of fluoride in tea liquids is higher when
it’s prepared using repeated infusion, but it’s lower when the tea has been
prepared using the continuous infusion method. Tea brands (2) and (4) released
the highest level of flouride 7.37mg/L and 5.01mg/L respectively, which are
very high levels comparing to the other brands which released between 1.5mg/L
to 2.7mg/L. To prevent fluoride from reaching poising levels, the total daily
consumption of black tea liquid of brands (2) and (4) should not exceed 1.76L
and 2.58L respectively and to avoid preparing them using the repeated and
countinous infusion methods.
Total polyphenols (TP), total flavonoids (TF) and (-)-epigallocatechin gallate
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brewing time between 5-180 min.
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