У оквиру семинара Лабораторије за фотоакустику Института за физику у Београду, у четвртак, 22. фебруара 2024. године у 10 часова у читаоници билиотеке „др Драган Поповић“, проф. др Младен Франко (Лабораторија за животну средину и науке о животу, Универзитет у Новој Горици, Словенија) одржаће предавање:
Effects of Photodegradation in Thermal Lens Spectrometric Measurements and their Mitigation
САЖЕТАК:
Most analytical applications of thermal lens spectrometry (TLS) and related theoretical models consider the absorbance of the sample constant during a single excitation by the pump laser beam. For photolabile analytes, intensive excitation light can cause photodegradation, significantly affecting TLS measurement results. Theoretical models will be presented that account for changes in concentration and consequent changes in absorbance, caused by chemical reactions of different orders [1,2]. Furthermore, TLS signal transients were observed for fast photochemical reactions on a millisecond time scale, and the contributions of photodegradation and molecular diffusion were analyzed in detail [3]. In this presentation, a comparison of theoretical predictions and experimental results will be presented. It will be furthermore demonstrated that the effects of photodegradation can be successfully reduced by performing TLS measurements in flowing systems such as in the case of flow injection analysis (FIA) [4] or
microfluidics [5].
У читаоници библиотеке „др Драган Поповић“ у 11 часова проф. др Младен Франко одржаће предавање:
Applications of Thermal Lens Spectrometry in Photochemistry and Photocatalysis
САЖЕТАК:
The findings on the effects of photochemical reactions on TLS signal were utilized to study the kinetics of chemical reactions [6,7], processes such as photostability of the soybean oil [8] and thermal stability of biodiesel [9], or to improve the sensitivity of TLS detection in case of photolabile analytes [10,11]. Furthermore, in combination with the concept of biomolecular recognition, FIA-TLS was exploited to study the efficiency of degradation and removal of some neurotoxic substances, such as organophosphate insecticides, and has confirmed photocatalysis as a proper method, which prevents the formation of degradation products with higher toxicity than parent compounds, as it was observed for example during ozonation monitored by TLS [12]. The high sensitivity of TLS has enabled discrimination between photocatalytic and photosensitization mechanisms in photocatalytic degradation of textile dyes [13], as well as discrimination between photodegradation and photocatalysis as will be demonstrated by the results of the latest research in this field [14]. will be given by Prof. Dr. Mladen Franko, Laboratory for Environmental and Life Sciences, University of Nova Gorica (https://www.ung.si/en/), Nova Gorica, Slovenia (mladen.franko@ung.si)
References:
[1] M. Franko and C.D. Tran, Rev. Sci. Instrum. 62, 2430-2437 (1991).
[2] M. Franko and C.D. Tran, Rev. Sci. Instrum. 62, 2438-2442 (1991).
[3] P.R.B. Pedreira, L.R. Hirsch, J.R.D. Pereira, A.N. Medina, A.C. Bento, M.L. Baesso, M.C.E. Rollemberg, M. Franko, and J. Shen, J. Appl. Phys. 100, 044906 (2006).
[4] A. Madžgalj, M.L. Baesso, and M. Franko, Eur. Phys. J. Special Topics 156, 503-506 (2008).
[5] M. Liu, S. Malovrh, and M. Franko, Anal. Methods 8, 5053-5060 (2016).
[6] M. Franko and C.D. Tran, Rev. Sci. Instrum. 62, 2438-2442 (1991).
[7] P.R.B. Pedreira, L.R. Hirsch, J.R.D. Pereira, A.N. Medina, A.C. Bento, M.L. Baesso, M.C.E. Rollemberg, M. Franko, and J. Shen, J. Appl. Phys. 100, 044906 (2006).
[8] E.L. Savi, L.C. Malacarne, M.L. Baesso, P.T.M. Pintro, C. Croge, J. Shen, and N.G.C. Astrath, Spectrochim. Acta A 145, 125–129 (2015).
[9] E.L. Savi, L.S. Herculano, G.V.B. Lukasievicz, H.R. Regatieri, A.S. Torquato, L.C. Malacarne, N.G.C. Astrath, Fuel, 217, 404-408 (2018).
[10] A. Madžgalj, M.L. Baesso, and M. Franko, Eur. Phys. J. Special Topics 156, 503-506 (2008).
[11] M. Liu, S. Malovrh, and M. Franko, Anal. Methods 8, 5053-5060 (2016).
[12] M. Bavcon Kralj, P. Trebše, and M. Franko, TrAC, Tends Anal. Chem. 26, 1020-1031 (2007).
[13] Z. Ebrahimpour, M. Abdelhamid, O. Pliekhova, K. Gadejisso-Tossou, H. Cabrera, D. Korte, J. Niemela, U. Lavrenčič Štangar, and M. Franko, Spectrochim. Acta A: Mol. Biomol. Spectrosc. 252, 119481, (2021).
[14] L. Godec, S.N. Sindhu, Research report, University of Nova Gorica, (paper in preparation) 2023.