Title Toksikološki i forenzični značaj kofeina- određivanje koncentacije kofeina u raznim napicima
Title (english) Toxicological and forensic significance of caffeine -determination of caffeine concentration in various beverages
Author Lucija Bardić
Mentor Renata Odžak (mentor)
Committee member Renata Odžak (predsjednik povjerenstva)
Committee member Ivan Jerković (član povjerenstva)
Committee member Željana Bašić (član povjerenstva)
Granter University of Split University Department of Forensic Sciences Split
Defense date and country 2020-09-28, Croatia
Scientific / art field, discipline and subdiscipline NATURAL SCIENCES Chemistry
Abstract Cilj: Cilj ovog rada je kroz pregled literature opisati kemijska svojstva i toksikološki učinak kofeina uz osvrt na njegov forenzični značaj. Eksperimentalnom dijelu rada cilj je UV-VIS spektrometrijom odrediti koncentraciju kofeina u 19 odabranih uzoraka čajeva, osvježavajućih bezalkoholnih i energetskih pića dostupnih na hrvatskom tržištu. Također, potrebno je ispitati slažu li se dobivene koncentracije kofeina sa zakonski propisanim maksimalnim sadržajem kofeina u određenom tipu napitka.
Metode: Pomoću standardnih otopina kofeina poznatih koncentracija i njihovih apsorbancija izmjerenih UV-VIS spektrometrom pri valnoj duljini 274 nm, konstruiran je baždarni dijagram i određena njegova jednadžba pravca. Infuzija uzoraka čaja izvršena je u destiliranoj vodi, nakon čega je smjesa filtrirana, a filtrat miješan s kloroformom u lijevku za odjeljivanje. Uzorci osvježavajućih bezalkoholnim i energetskih pića degazirani su zagrijavanjem do ključanja i nakon toga ekstrahirani kloroformom u lijevku za odjeljivanje. Tako dobiven ekstrakt je razrijeđen, te mu je UV-VIS spektrometrom mjerena apsorbancija pri valnoj duljini od 274 nm. Koncentracije kofeina u uzorcima izračunate su s pomoću jednadžbe pravca baždarnog dijagrama i faktora razrijeđenja ekstrakata.
Rezultati: Rezultati ovog istraživanja su sukladni do sada provedenim sličnim istraživanjima. Uzorci crnih čajeva sadrže veće koncentracije kofeina u odnosu na zelene, dok čajevi skupno imaju više određene koncentracije od ostalih analiziranih napitaka. Energetska pića sadrže veću koncentraciju kofeina u odnosu na osvježavajuće bezalkoholne napitke kod kojih dijetalne inačice određenih napitaka imaju manju koncentraciju kofeina od svojih originalnih varijanti. Dva uzorka energetskih pića pokazala su veću koncentraciju kofeina od one preporučene. Ostali uzorci sadrže koncentracije kofeina u granicama zakonski dozvoljenog, a na deklaracijama proizvoda navode se sve propisane informacije.
Zaključak: Budući da je kofein najčešće konzumirana psihoaktivna tvar, njegov toksikološki utjecaj na ljudski organizam dobro je istražen. Forenzični značaj kofeina je malen, ali je potrebno povećati svijest o negativnom utjecaju i mogućoj zlouporabi, na tržištu lako dostupnog, čistog kofeina. Metoda određivanja koncentracije UV-VIS spektometrijom izuzetno je jednostavna, brza, jeftina i pouzdana. Ipak, postupak ekstrakcije nije pokazao dobru ponovljivost zbog čega ga kroz buduća istraživanjima treba dodatno prilagoditi smanjenjem broja koraka u protokolu i mogućeg utjecaja ljudskog faktora na rezultate.
Abstract (english) Objective: The aim of this paper is to describe the chemical properties and toxicological effect of caffeine through a review of the literature with reference to its forensic significance. The aim of the experimental part of the paper is to determine the concentration of caffeine in 19 selected samples of teas, refreshing soft and energy drinks available on the Croatian market by UV-VIS spectrometry. Also, it is necessary to examine whether the obtained concentrations of caffeine comply with the legally prescribed maximum caffeine content in a particular type of beverage.
Methods: Using standard solutions of caffeine of known concentrations and their absorbances measured by UV-VIS spectrometer at a wavelength of 274 nm, a calibration diagram was constructed and its equation was determined. The tea samples were infused in distilled water, after which the mixture was filtered and the filtrate mixed with chloroform in a separatory funnel. Samples of refreshing soft and energy drinks were degassed by heating to boiling and then extracted with chloroform in a separatory funnel. The extract thus obtained was diluted and its absorbance was measured by UV-VIS spectrometer at a wavelength of 274 nm. Caffeine concentrations in the samples were calculated using the calibration equation and the extract dilution factor.
Results: The results of this research are consistent with similar research conducted so far. Samples of black teas contain higher concentrations of caffeine compared to green ones, while teas collectively have higher specific concentrations than other beverages analyzed. Energy drinks contain a higher concentration of caffeine compared to refreshing soft drinks in which the dietary versions of certain beverages have a lower concentration of caffeine than their original variants. Two samples of energy drinks showed a higher concentration of caffeine than the recommended one. Other samples contain concentrations of caffeine within the limits allowed by law, and all prescribed informations are stated on product declarations.
Conclusion: Since caffeine is the most commonly consumed psychoactive substance, its toxicological impact on the human body has been well investigated. The forensic significance of caffeine is small, but there is a need to increase awareness of the negative impact and possible misuse of pure caffeine which is easily available on the market. The method of determining the concentration by UV-VIS spectrometry is extremely simple, fast, cheap and reliable. However, the extraction process did not show good repeatability, which is why it should be further adjusted through future research by reducing the number of steps in the protocol and the possible influence of the human factor on the results.
Keywords
forenzična toksikologija
kofein
UV-VIS spektometrija
Keywords (english)
forensic toxicology
caffeine
UV-VIS spectrometry
Language croatian
URN:NBN urn:nbn:hr:227:114750
Study programme Title: Forensic Sciences Study programme type: university Study level: graduate Academic / professional title: magistar/magistra forenzike (magistar/magistra forenzike)
Type of resource Text
File origin Born digital
Access conditions Open access
Terms of use
Created on 2020-11-27 12:44:12