Detailed Information on Publication Record
2015
Content of 4(5)-methylimidazole, caffeine and chlorogenic acid in commercial coffee brands
DIEU PHAN, Thi Thanh, Miroslava BITTOVÁ, Kamil MIKULÁŠEK, Vlastimil KUBÁŇ, Stanislav KRÁČMAR et. al.Basic information
Original name
Content of 4(5)-methylimidazole, caffeine and chlorogenic acid in commercial coffee brands
Authors
DIEU PHAN, Thi Thanh (203 Czech Republic, guarantor), Miroslava BITTOVÁ (203 Czech Republic, belonging to the institution), Kamil MIKULÁŠEK (203 Czech Republic, belonging to the institution), Vlastimil KUBÁŇ (203 Czech Republic), Stanislav KRÁČMAR (203 Czech Republic), Pavel VALÁŠEK (203 Czech Republic) and Blanka SVOBODOVÁ (203 Czech Republic)
Edition
Potravinárstvo, 2015, 1337-0960
Other information
Language
English
Type of outcome
Článek v odborném periodiku
Field of Study
10406 Analytical chemistry
Country of publisher
Slovakia
Confidentiality degree
není předmětem státního či obchodního tajemství
References:
RIV identification code
RIV/00216224:14310/15:00083015
Organization unit
Faculty of Science
Keywords (in Czech)
káva, spektrofotometrické metody, HPLC, extrahovatelnost kofeinu
Keywords in English
coffee; spectrophotometric methods; HPLC; caffeine extractability
Změněno: 1/6/2015 16:20, Mgr. Miroslava Bittová, Ph.D.
Abstract
V originále
Content of 4(5)-methylimidazole(4-MeI), caffeine and chlorogenic acid in commercial coffee brands were determined using high-performance liquid chromatography (HPLC) with UV DAD and MS detectors. Positive ion ESI mass spectra of the 4-MeI standard yielded intense signals corresponding to [M+H]+(83.0604) and [2M+H]+ions (165.1115). Also, adducts of 4-MeI with acetonitrile from mobile were detected –[M+ACN]+ions (124.0849). The LOD of 2.5 ng mL-1and LOQ of 8.4 ng.mL-1 were calculated according to the following formulas: LOD = 3.SD/S, and LOQ = 10.SD/S, where S is the slope of the calibration curve and SD is the standard deviation of the noise. The caffeine content was compared to the results of the standard addition, 1stderivative and liquid-liquid extraction spectrophotometry. 4-MeI was in tens mikrog g-1 in the Vietnamese coffees while in units mikrog.g-1in all Czech and Brazilian coffees (<2.4 mikrog.g-1 and <4.9 mikrog.g-1 , respectively). The results for caffeine were within the documented range (0.31 – 2.20%) in all coffee samples. The lower content of caffeine and chlorogenic acid was observed in Vietnamese coffees. All the methods used for determination of caffeine in the Czech and Brazilian coffees gave acceptable precision an d accuracy. However, there were significant differences in the results in Vietnamese coffees. The caffeine extractability (100 °C, 3 min brewing) almost reached 100% in Czech and Brazilian coffees, while it was less than 90% in Vietnamese coffees. The Czec h and Brazilian coffees tend to produce more caffeine in brews than the Vietnamese coffee because of the different composition of blends and the particle size degree.
Links
| MUNI/A/1452/2014, interní kód MU |
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