Določevanje hidrogentartrata v vzorcih vinskega kamna s potenciometrično titracijo

Jančigaj, Eva (author), Kočar, Drago (mentor)

V diplomski nalogi sem določevala masni delež kalijevega hidrogentartrata v vinskem kamnu treh vzorcev. Za določitev sem uporabila tri postopke: titracijo z NaOH(aq) filtriranih in nefiltriranih raztopin vzorcev, retitracijo z NaOH(aq) in s HCl(aq) filtriranih in nefiltriranih raztopin vzorcev in pa titracijo z NaOH(aq) samih vzorcev. Uporabila sem avtomatski potenciometrični titrator, s kombinirano stekleno elektrodo. Pri vseh vzorcih sem določila zelo visoke deleže KHT, saj je to glavna sestavina vinskega kamna. Pri vinskem kamnu rdečega vina je bil masni delež KHT nekoliko manjši, kar sem povezala s tem, da tak kamen vsebuje tudi veliko celic kvasovk. Zanimivo je, da sem pri titraciji in retitraciji filtriranih in nefiltriranih raztopin istih vzorcev določila različne deleže, kar kaže na to, da v vinskem kamnu obstajajo še druge spojine, ki reagirajo s klorovodikovo kislino in raztopino natrijevega hidroksida. Za razumevanje tega bi morala analizirati spojine, ki so poleg KHT še prisotne v vinskem kamnu.

• Language: Slovenian
• Keywords: hidrogentartrat, vinski kamen, titracija, retitracija
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2019
• PID: 20.500.12556/RUL-109510
• COBISS.SI-ID: 1538311107
• Publication date in RUL: 04.09.2019

Secondary language

• Language: English

Abstract

The purpose of my research was to determine the mass fraction of a potassium hydrogen tartrate in three samples of cream of tartar by three different titrations. I completed titrations of filtered and unfiltered solutions of samples with NaOH(aq) and with retitrations of added NaOH(aq) in the same solutions with HCl(aq). I also did titrations of samples diluted in deionized water with NaOH(aq). I used an automatic potentiometric titrator with a combined glass electrode. My results showed high mass fractions of KHT, which is expected, as KHT is the main component of cream of tartar. The cream of tartar of red wines may contain a large number of yeast cells, which results in lower mass fraction of KHT. I observed that results obtained by titration and retitration of filtered and unfiltered solutions of cream of tartar were considerably different, which could be the aftereffect of presence of other compounds that react with HCl(aq) and NaOH(aq).For a better understanding of said reactions, I would have to perform further analysis of cream of tartar to determine which compounds are actually present.

• Keywords: hydrogen tartrate, cream of tartar, titration, retitration