Új szervesanalitikai eljárások kidolgozása, alapkutatási és különleges feladatok megoldására szolgáló, mátrixspecifikus (természetes és biológiai) alapkutatási szinten = Development of new organic analytical methods, proper for various, special natural and biological matrices: both on the basic research and on the practical research levels

1. Az aminosavak és aminok, eltérő SH csoportú o-ftálaldehid reagenssel képzett termékeinek sztöchiometria/szerkezet/stabilitás összefüggéseit nagyhatékonyságú folyadékkromatográfiás elválasztások után, párosított fotodiodasoros (DAD)-fluoreszcenciás (Fl), s DAD-tömegspektrometriás (MS) eljárásokkal mértük. Bizonyítottuk, hogy az SH- segédanyagok közül, a más csoportot nem tartalmazó etántiol (ET) a legkedvezőbb: -mind az NH2-CH2 molekulaszerkezetű primer aminok OPA-ET termékeinek stabilitása, -mind a primer/szekunder amin, spermidin és spermin OPA-ET-9-fluorenilmetil klorformát (FMOC) származékainak sztöchiometrikus összetétele, azaz, e származékok analitikai hasznosíthatósága tekintetében. 2. A szacharidok, polialkoholok, karbonsavak, amino és fenolsavak, trimetilszilil (TMS)-(oxim) éter/észterek-ként, gázkromatográfiás (GC-MS) elemzőrendszerünket, -a rendszerbe iktatott releváns vegyületek (8 flavonoid, 3 antocianidin, 1 flavonol, 2 flavanon, 7 antrakinon s gyógyszermolekulák) származék-készítési és szelektív fragmentum analitikai tanulmányával, -a redukáló/nem redukáló szacharidok specifikus fragmentációjával, s -az elemzendő mátrixok (haszonnövények, nagyhatékonyságú drogok, környezeti vizek) választékával gyarapítottuk. Bebizonyosodott, hogy a GC-MS és a HPLC-MS együttes alkalmazása, a technikák külön-külön felhasználásá-hoz képest hatványozott többletinformációt tartalmaz. | 1. The stoichiometry/structure/stability relations of the OPA-amino acid/amine derivatives, containing various SH-additives, were separated by high-performance liquid chromatography, applying combined photodiode array/fluorescence (DAD-FL) and DAD-mass selective (MS) detections. It has been proved that out of the SH-additives, ethane-thiol is to be preferred, providing -the optimum stability of the NH2-CH2 moiety containing OPA-derivatives of primary amines, and -the expected, theoretical composition of the OPA-ET-FMOC-derivatives of the primary/secondary amines, spermidine and spermine; i.e. derivatization characteristics of primary importance in terms of analytical utility. 2. Our analytical system suitable for the identification and quantification of saccharides, polyalcohols, carboxylic, amino and phenolic acids, measured as their trimethylsilyl (TMS) ?(oxime) ether/ester derivatives by gas chromatography-mass spectrometry (GC-MS) has been extended: -by the insertion of relevant additional compounds into our analytical system (8 flavonoids, 7 anthraquinones, several pharmaceuticals), based on the study of their derivatization and selective fragmentation pattern analysis, -by the specific fragmentations of reducing/non reducing saccharides, and, -by the choice of the matrices to be analyzed. It was shown that the simultaneous application of the GC-MS and HPLC-MS techniques furnished exponentially more information compared to any of them alone

Simultaneous analysis of free amino acids and biogenic amines in honey and wine samples using in loop orthophthalaldeyde derivatization procedure

This work presents a RP-HPLC method for the simultaneous quantification of free amino acids and biogenic amines in liquid food matrices and the results of the application to honey and wine samples obtained from different production processes and geographic origins. The developed methodology is based on a pre-column derivatization with o-phthaldialdehyde carried out in the sample injection loop. The compounds were separated in a Nova-Pack RP-C18 column (150 mm × 3.9 mm, 4 μm) at 35 °C. The mobile phase used was a mixture of phase A: 10 mM sodium phosphate buffer (pH 7.3), methanol and tetrahydrofuran (91:8:1); and phase B: methanol and phosphate buffer (80:20), with a flow rate of 1.0 ml/min. Fluorescence detection was used at an excitation wavelength of 335 nm and an emission wavelength of 440 nm. The separation and quantification of 19 amino acids and 6 amines was carried out in a single run as their OPA/MCE derivatives elute within 80 min, ensuring a reproducible quantification. The method showed to be adequate for the purpose, with an average RSD of 2% for the different amino acids; detection limits varying between 0.71 mg/l (Asn) and 8.26 mg/l (Lys) and recovery rates between 63.0% (Cad) and 98.0% (Asp). The amino acids present at the highest concentration in honey and wine samples were phenylalanine and arginine, respectively. Only residual levels of biogenic amines were detected in the analysed samples

Voltametrické stanovení taurinu v energetických nápojích po derivatizaci o-ftalaldehyd-ethanethiolem

A completely new voltammetric method has been developed for quantitative determination of food additive Taurine (Tau) in energy drinks. This electroanalytical method is based on voltammetric oxidation of o-phthalaldehyde-ethanthiol derivative of Tau at glassy carbon electrode in 95% methanol containing 0.1 mol L−1 lithium perchlorate. Working conditions necessary for quantitative Tau derivatization reaction and electrochemical detection using square wave voltammetry were optimized. Linear range from 1.0×10−5 to 1.0×10−4 mol L−1 characterized by coefficient of determination 0.9998, limits of quantification 6.8×10−6 mol L−1 and detection 2.1×10−6 mol L−1 were obtained at pulse amplitude 50 mV and frequency 80 Hz. Analytical method of calibration curve was used for evaluation of Tau content in several commercially available energy drinks. The procedure was validated using standard reference high performance liquid chromatography (HPLC) method. Both methods showed nearly identical Tau content, around 0.35% (w/w). Besides its reliability to the Tau determination, that is totally comparable to reference method used, present voltammetric approach is more advantageous on the economic and simplicity basis. Finally, developed voltammetric method could find employment in food quality control.Pro kvantitativní stanovení potravinářské přídatné látky Taurinu (Tau) v energetických nápojích byla vyvinuta zcela nová voltametrická metoda. Tato elektroanalytická metoda je založena na voltammetrické oxidaci o-ftalaldehydu-ethanthiolovém derivátu Tau na elektrodě ze skelného uhlíku v 95% methanolu obsahující 0,1 mol L-1 chloristanu litného. Pracovní podmínky nezbytné pro kvantitativní Tau derivatizační reakci a elektrochemickou detekci pomocí square wave voltametrie byly optimalizovány. Lineární rozsah od 1,0 × 10−5 do 1,0 × 10−4 mol L − 1 charakterizovaný koeficientem stanovení 0,9998, mezí kvantifikace 6,8 × 10 - 6 mol L − 1 a detekce 2,1 × 10–6 mol L − 1 byly získány při amplitudě 50 mV a frekvenci 80 Hz. Analytická metoda kalibrační křivky byla použita pro vyhodnocení obsahu Tau v několika komerčně dostupné energetických nápojích. Postup byl validován pomocí standardní referenční vysokoúčinné kapalinové chromatografie (HPLC). Obě metody vykazovaly téměř identický obsah Tau, kolem 0,35% (hm / hm). kromě jeho spolehlivost vůči stanovení Tau, která je zcela srovnatelná s použitou referenční metodou, je voltametrický přístup je výhodnější z ekonomického hlediska a instrumentální náročnosti. Závěrem lze konstatovat, že vyvinutá metoda by mohla najít uplatnění v kontrole kvality potravin