National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Determination of biologically active compounds in hops by LC/HR-MS method
Jandovská, Vladimíra ; Sobotníková, Jana (advisor) ; Spáčil, Zdeněk (referee)
This thesis describes development and optimalization of method for identification of polyphenols compounds present in hops (Humulus lupulus L.) that have potential antimicrobial activity. Within extraction of compounds from hop, minced hop cones were applied in a growth medium, where compounds diffused into the medium and created an inhibition zone after inoculated with Streptococcus aureus. The method combining extraction with acetone a salting out using QuEChERS principles was optimized for extraction of compounds from solid growth medium. The analysis was carried out using LC/HR-MS with a quadrupole-orbitrap hybrid mass analyzer. The MS method was developed as a screening method with a subsequent fragmentation of compound of interest on the base of inclusion mass list. The compounds extracted from inhibition zone were identified either by searching against a database or their structures have been elucidated on the basis of their fragmentation spectra.
Determination of iron in beer using atomic absorption spectroscopy
Jandovská, Vladimíra ; Tesařová, Eva (advisor) ; Frantík, František (referee)
This thesis describes the development and optimisation of a method for determination of iron in beer using electrothermal atomic absorption spectroscopy as a more sensitive option to routinely used flame atomic absorption spectroscopy. While a fully functional method has been developed for aqueous solutions, matrix effects in real beer samples made this determination impossible. Therefore, a method of sample preparation has been developed, beer purifying through column with adsorbent Florisil. After this adjustment the interfering substance was eliminated and the detection limit of ETAAS was six times lower than the detection limit of FAAS. The content of iron in the real beer sample using ETAAS was measured as 30 % lower than using FAAS, it is therefore necessary to optimise this method. This will be the subject of further experiments.

Interested in being notified about new results for this query?
Subscribe to the RSS feed.