Adéla Fuxová’s thesis, titled '2D LA-ICP-MS imaging as a tool for evaluating the efficacy of chemotherapy', makes a valuable contribution to the research topic of my team, which is devoted to the application of the LA-ICP-MS method in oncology. The thesis is based on experimental work conducted at King's College London, focusing on tumour tissue analysis using a time-of-flight (ToF) analyser with simultaneous isotope separation, combined with a laser ablation system that emits radiation at a wavelength of 193 nm. The thesis aimed to establish the effectiveness of using LA-ICP-MS with a quadrupole analyser to study drug efficacy based on 2D mapping of tumour tissue before and after chemotherapy. This evaluation was based on investigating the distribution of platinum originating from the administration of carboplatin to patients, as well as studying changes in the distribution of metalloproteins, which are components involved in tumour tissue resistance.

Despite lacking prior hands-on experience with the LA-ICP-MS method, the student approached the problem with enthusiasm and quickly mastered the necessary practical skills to achieve the desired results. She concentrated on preparing quantification standards and identified the limitations of the proposed quantification procedure, which will support further experimental work. Thanks to her work, a new methodology for the 2D analysis of multiple elements in soft tissues has been introduced at the Faculty of Chemistry, BUT. This makes it possible to clearly assess the impact of treatment on the distribution of selected elements and thus evaluate tumour chemoresistance as well as efficacy.

The presented work is very carefully written, the Introduction and theoretical sections clearly and concisely explain the issues surrounding anticancer drugs, such as cisplatin and carboplatin, as well as the role of Cu, Fe, Zn, P, Pt, and S, which are present in tissues. Next part is a critical review of methods suitable for monitoring the distribution of these elements in tissues, the preparation of gelatin calibration standards, verification of their suitability, the preparation of samples containing cancerous tissues, and their analysis by LA-ICP-MS. Calibration of the LA is certainly a challenging process, so it would be better to avoid linear plotting the full calibration range  (Figs. 16–18). The detailed analysis of the elemental maps is supported by the currently known behavior of the elements under study in the investigated tissues, as described in the extensive literature. The student proved remarkable skills and knowledge in both analytical chemistry and medicine. The bibliography at the end of the thesis contains 90(!) entries, and the only criticism is the inconsistent use of full names and initials. The thesis structure is usual, its level is high in any aspect, minimum typos. The visual representation of certain workflows is very user-friendly.  I have only a few little remarks:
P. 19 - "laser spot size" makes me no sense in XRF.
P. 24, 25 - Sector Field (SF) is simultanesous  when connected with a multicollector, Time Of Flight (TOF) is sequential in principle, but much faster than QMS, the statement is corrected on p. 25, "…resolution (defined as 10% mass peak height)…" is a peak width at the 10% height?
P. 28 - "Hydrochloric acid, HCl (98 % v/v)"?!
P. 39, Tab. 7 - "make-up gas" was not used although He was a carrier gas? 
P. 11 and further - In my opinion, the literature-based explication regarding the role of copper, based on its absence or presence in combination with the absence or presence of platinum, is not very conclusive in terms of cause and effect. However, this goes beyond the scope of the thesis, and the candidate was unable to resolve this issue. Topics for thesis defence:

1. 1. P. 13 - "Evidence for Be mutagenicity is limited…"? Isn´t Be clearly carcinogenic?
2. 2. P. 35 - What was the pH of the physiological buffer solution if HCl was added to achieve a pH of 7.4–7.5?
3. 3. P. 39 and following - how was a potential interference of 56Fe with 40Ar16O addressed and why did you choose just 56Fe? You generally mention a collision cell, but I would appreciate a more detailed explanation.
4. 4. P. 39 and Tab. 8 - How was it ensured that the laser beam remained in the same spot for 4 pulses? Is the translation speed given an average value?
5. 5. Figs. 17, 18 - did you measure depths of craters and did you consider a longer integration time (not found in Parameters of ICP-MS) because of low counts?