[institut] Seminars - Laboratory for Photoacoustics - Thursday, February 22, 2024, at 10:00 - Library reading room "Dr Dragan Popović"

[Dr. Dragan D. Markushev]

Dear colleagues,

You are cordially invited to the seminars organized by the Laboratory 
for Photoacoustics, held on Thursday, February 22, 2024, at 10:00, in 
the library reading room "Dr Dragan Popović" of the Institute of Physics 
Belgrade.

The talks entitled:

10.00-10.45 "Effects of Photodegradation in Thermal Lens Spectrometric 
Measurements and their Mitigation"

Abstract:
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].

and

11.00-11.45 "Applications of Thermal Lens Spectrometry in Photochemistry 
and Photocatalysis"

Abstract:
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 at 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.

Best regards,

Dragan D. MARKUSHEV

-- 
Dr. Dragan D. MARKUSHEV
Principal Research Fellow
Photonics Center
Head of the Laboratory for Photoacoustics
Institute of Physics Belgrade
Pregrevica 118,
11080 Belgrade, SERBIA
cell: +381603169816
phone: +381113713158
fax: +381113162190
http://photonics.ipb.ac.rs/
http://www.ipb.ac.rs/