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1.
Thermal lens spectrometry - still a technique on the horizon?
Mladen Franko, 2015

Abstract: In 1980’s thermal lens spectrometry (TLS) was still considered as a “spectrometric technique on the horizon” as one can also read from one of the textbooks on spectrochemical analysis of that time. Intensive development of thermal lens instrumentation and methods of chemical analysis and material characterisation has however resulted in substantial progress in this field, which is evident from important instrumental innovations and first commercial instruments (i.e. thermal lens microscopes -TLM) designed for lab-on-a-chip chemistry as well as from novel applications of TLS in various areas, where highly sensitive and rapid chemical analysis of complex samples is needed, including food safety and quality control, environmental analysis and biomedical diagnostics. This presentation is a review of most significant contributions and applications of thermal lens spectrometry, with emphasis on most recent achievements in instrumentation, which culminated into construction of novel optimized TLM instruments, capable of exploiting the tuneability of incoherent light sources and enabled novel applications particularly in micro-fluidics. Based on latest progress relying on bio-analytical assays and micro-fluidic flow injection with TLM detection we have also witnessed firs routine applications of TLS in analytical and diagnostic laboratories, which on wine side actually classifies TLS as a conventional and routine analytical tool, but at the same time opens new horizons for development and applications of this ultrasensitive and rapid spectrometric technique.
Found in: ključnih besedah
Keywords: Thermal lens spectrometry, applications, Liquid chromatography, flow injection analysis, bioanalytical methods
Published: 29.03.2016; Views: 1991; Downloads: 0
.pdf Fulltext (609,15 KB)

2.
Thermal Lens Spectrometry: Still a Technique on the Horizon
Mladen Franko, Mingqiang Liu, 2016, published scientific conference contribution

Abstract: In this article the historical development of thermal lens spectrometry (TLS) is briefly reviewed for introduction. In continuation, the emphasis is on the recent progresses of TLS for measurements in ensembled sample cells and in microfluidic flow injection systems. Novel theories, instrumentations and their applications for high sample throughput environmental, chemical and biomedical analysis, particularly in micro space, are presented. Discussions are given on the limitations of present TLS systems, that open new horizons for future progress of this technique, which has already found place among routine techniques for chemical analysis. In the last part, proposals for the future development of TLS toward advanced applications in new research fields are presented.
Found in: ključnih besedah
Keywords: Thermal lens spectrometry, Microfluidic chip, Chemical analysis, Environmental monitoring, Biomedical assay
Published: 17.05.2016; Views: 1749; Downloads: 0
.pdf Fulltext (404,46 KB)

3.
Application of complex geometrical optics to determination of thermal, transport, and optical parameters of thin films by the photothermal beam deflection technique
Dorota Korte Kobylinska, Mladen Franko, 2015, original scientific article

Found in: ključnih besedah
Summary of found: ... spectrometry, photothermal beam, geometrical optics, thin films, ...
Keywords: spectrometry, photothermal beam, geometrical optics, thin films
Published: 16.06.2016; Views: 1533; Downloads: 50
URL Fulltext (0,00 KB)

4.
Highly Sensitive Determination of Pyoverdine in Cloud Water by HPLC-Thermal Lens Spectrometry
Leja Goljat, Mitja Martelanc, Virginie Vinatier, Anne-Marie Delort, Mladen Franko, 2016, published scientific conference contribution abstract

Abstract: New method for pyoverdine and Fe(III)-pyoverdine detection was developed. Two isomers of pyoverdine and two isomers of Fe(III)-pyoverdine were separated isocraticaly on reversed-phase (RP)-C18 chromatograhic column and detected by DAD, FLD and TLS. HPLC-TLS method enables separation and determination of pyoverdine and Fe(III)-pyoverdine in a single run and excels in superior sensitivities when compared to conventional HPLC-DAD system.
Found in: ključnih besedah
Keywords: Pyoverdine, Fe(III)-pyoverdine, cloud water, high-performance liquid chromatography, thermal lens spectrometry
Published: 04.07.2016; Views: 1916; Downloads: 0

5.
RAPID UPLC-ESI-MS/MS BASED ASSAY FOR DISCOVERY OF UDP-N-ACETYLMURAMOYL-L-ALANINE:D-GLUTAMATE (MurD) LIGASE INHIBITORS
Vjekoslava Car, 2016, master's thesis

Abstract: A rapid, selective, robust and sensitive analytical assay method, operating in a short time frame with acceptable levels of precision, linear range and the accuracy necessary for successful Mur ligases inhibitors discovery, was developed. An LC-MS/MS analytical procedure was designed for the determination of a MurD ligase reaction product (UMAG). The special focus of this work was on UDP-N-acetylmuramyl-L-alanine:D-glutamate ligase (MurD) activity. The assay method is especially valuable as an orthogonal (secondary) assay for the primary high throughput fluorescent-based assay screening of potential Mur ligase inhibitors. The LC-MS/MS assay is fully compatible with the components from the primary fluorescent-based assay and enables the analysis of the same samples by both methodologies. The presented LC-MS/MS assay procedure is used for the evaluation of the false positive hits (molecules) from the primary, fluorescence based, high throughput screening assay experiments. This is important for the elimination of false positive hits from the prohibitively expensive and time-consuming investigation process. Method development describes the evaluation and optimization of the various stages of sample preparation, chromatographic separation, MS/MS determination and quantification. An enzyme reaction is performed in a 96-well plate. The quenched reaction mixture samples were spiked with an internal standard (phenacetin). The permeate was injected onto the U(H)PLC-MS/MS triple quadrupole system after sample ultrafiltration. Chromatographic separation was achieved on the ACQUITY UPLCTM HSS T3 column (100 x 2.1 mm i.d., 1.8 µm particle size) using an ammonium format buffer at pH 2.8 and acetonitrile as eluent. Elution initiated with an isocratic-hold for 1.1 min, followed by a two-step linear gradient of up to 3 min, giving a total run time of 5 min including equilibration. The flow rate was kept at a constant 0.4 mL/min. UMAG quantitative analysis was performed by positive electrospray ionization, followed by tandem mass spectrometry (ESI-MS/MS). The analytical assay quantifies UMAG in a linear range from 0.25 to 20 µM using 70 µL of samples. Validation results demonstrated that UMAG concentrations can be accurately and precisely determined in samples from the primary assay. Evaluation of inhibitory activities of compounds measured by both the fluorescence and the LC-MS/MS method demonstrated that the values were in a very good agreement. This analytical method can be used to screen a compound library at a defined concentration of each compound to obtain the percentage of inhibition, or with a series of compound concentrations to obtain inhibition potency of a compound (IC50). The selected Lek compounds no. 1 and 2 from the virtual screening campaign were presented, tested and further investigated due to the expression of significant MurD ligase inhibitory action acquired by primary high throughput tests. This assay has been developed for MurD, but during development, chromatographic and MS/MS conditions for UM and UMA were studied and defined as well. Therefore, this analytical assay method can easily be applied to other Mur ligases (i.e. MurC, MurE) enzyme activity monitoring in the process of bacteria cell wall peptidoglycan formation. This method enables the identification of many different Mur ligase inhibitors in a continued search for new Gram positive and Gram negative bacteria antibiotics.
Found in: ključnih besedah
Summary of found: ...positive electrospray ionization, followed by tandem mass spectrometry (ESI-MS/MS). The analytical assay quantifies UMAG in...
Keywords: Mur ligases, UDP-N-acetylmuramyl-L-alanine:D-glutamate (MurD) inhibitors, UNAM-Ala-Glu, LC-MS/MS, liquid chromatography, tandem mass spectrometry, antibiotics, drug discovery
Published: 23.09.2016; Views: 2862; Downloads: 159
.pdf Fulltext (2,62 MB)

6.
Thermal Lens Spectrometry and Microscopy Analytical Chemist’s Approach
Mladen Franko, unpublished invited conference lecture

Abstract: This lecture introduces the basic concepts and recent progres in theory, instrumentation and applications of thermal lens spectrometry, thermal lens microscopy and their utilization for highly sensitive, and high throughput detection in liquid chromatography, flow injectionanalysis in microfluidic systems.
Found in: ključnih besedah
Keywords: Thermal lens spectrometry, TLS microscopy, theory, applications
Published: 01.03.2017; Views: 1349; Downloads: 1
.pdf Fulltext (17,07 MB)
This document has many files! More...

7.
Development and Validation of a High- Performance Liquid Chromatography– Tandem Mass Spectrometry Method for the Simultaneous Determination of Irinotecan and Its Main Metabolites in Human Plasma and Its Application in a Clinical Pharmacokinetic Study
Giuseppe Toffoli, Elena Marangon, Elisa Mazzega, Bianca Posocco, 2015, original scientific article

Abstract: Irinotecan is currently used in several cancer regimens mainly in colorectal cancer (CRC). This drug has a narrow therapeutic range and treatment can lead to side effects, mainly neutropenia and diarrhea, frequently requiring discontinuing or lowering the drug dose. A wide inter-individual variability in irinotecan pharmacokinetic parameters and pharmacodynamics has been reported and associated to patients’ genetic background. In particular, a polymorphism in the UGT1A1 gene (UGT1A1*28) has been linked to an impaired detoxification of SN-38 (irinotecan active metabolite) to SN-38 glucuronide (SN-38G) leading to increased toxicities. Therefore, therapeutic drug monitoring of irinotecan, SN-38 and SN-38G is recommended to personalize therapy. In order to quantify simultaneously irinotecan and its main metabolites in patients’ plasma, we developed and validated a new, sensitive and specific HPLC–MS/MS method applicable to all irinotecan dosages used in clinic. This method required a small plasma volume, addition of camptothecin as internal standard and simple protein precipitation. Chromatographic separation was done on a Gemini C18 column (3 μM, 100 mm x 2.0 mm) using 0.1% acetic acid/bidistilled water and 0.1% acetic acid/acetonitrile as mobile phases. The mass spectrometer worked with electrospray ionization in positive ion mode and selected reaction monitoring. The standard curves were linear (R20.9962) over the concentration ranges (10–10000 ng/mL for irinotecan, 1–500 ng/mL for SN-38 and SN-38G and 1–5000 ng/mL for APC) and had good back-calculated accuracy and precision. The intra- and inter-day precision and accuracy, determined on three quality control levels for all the analytes, were always <12.3% and between 89.4% and 113.0%, respectively. Moreover, we evaluated this bioanalytical method by re-analysis of incurred samples as an additional measure of assay reproducibility. This method wassuccessfully applied to a pharmacokinetic study in metastatic CRC patients enrolled in a genotype-guided phase Ib study of irinotecan administered in combination with 5-fluorouracil/ leucovorin and bevacizumab.
Found in: ključnih besedah
Keywords: Pharmacokinetic, pharmacodynamics, phase I clinical study, colorectal cancer, Mass spectrometry, pharmacogenetics
Published: 21.03.2017; Views: 1275; Downloads: 0
.pdf Fulltext (1018,06 KB)

8.
Comparison of Colorimetric Reagents and Their Applicability in Thermal Lens Spectrometry
Mladen Franko, Mikhail A. Proskurnin, Leja Goljat, 2017, published scientific conference contribution abstract

Found in: ključnih besedah
Keywords: thermal lens spectrometry, colorimetric reagents, mercury
Published: 30.08.2017; Views: 1134; Downloads: 0
.pdf Fulltext (71,63 KB)

9.
10.
DETERMINATION OF Fe2+ IN LIQUID SAMPLES BY THE USE OF AMPLIEFIED THERMAL LENS SPECTROMETRY
Humberto Cabrera, Dorota Korte, Leja Goljat, Mladen Franko, 2017, published scientific conference contribution abstract

Found in: ključnih besedah
Keywords: AMPLIEFIED THERMAL LENS SPECTROMETRY, Fe2+
Published: 30.08.2017; Views: 1216; Downloads: 0
.pdf Fulltext (12,87 MB)

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