Thirty-five years ago, Professors Rudolf Kaiser and Szabolcs Nyiredy launched the “Journal for Planar Chromatography – Modern TLC,” better known as JPC. Later, on the occasion of JPC’s first 20 years, Prof. Kaiser made a parallel between this beautiful age of the human being and the development of the journal.

In his editorial, he highlighted that high-performance thin-layer chromatography (HPTLC) was the most appropriate technique for cases in which the complexity of mixtures is too critical for classical column separations, and that it was the best analytical technique for optimizing production, because it can be simple, performed quickly, and very economical, without forgetting that it always uses a clean stationary phase free from memory effects. Likewise, he highlighted the important advances in pharmaceutical quality control, for environmental analysis, and for analysis of many highly complicated natural products.

Continuing with Prof. Kaiser’s parallelism, now the 35 years of JPC should still constitute a period of development, reaching maturity. In recent years, considerable progress has been made in instrumental development, in the standardization of parameters to yield reproducible results across multiple plates, and in the possibilities of planar detection. The possibility of performing multiple detection in a planar format is a strong differentiating feature of HPTLC versus other techniques. In addition to ultraviolet/fluorescence (UV/FL) scanning densitometry and videodensitometry, a variety of bioassays can be performed directly on the plate, as well as the direct recording of mass spectra, using practically any of the existing mass spectrometry (MS) techniques.

In this issue commemorating JPC’s 35th birthday, we have works that illustrate these points. In a review, Tién Do and Reich present a perspective on the evolution and future of HPTLC in routine quality control. For fingerprinting and identification of herbal (botanical) materials, a system suitability test (SST) on each plate is needed.

A work on parameters that influence standardization, in this case, humidity, is presented by Schuster and Oellig concerning the separation of organic esters, and mono- and diacylglycerol emulsifiers.

Several papers in this issue deal with different approaches to plant analysis. Lazovic et al. describe a green approach for the extraction and separation of phenols from Teucrium chamaedrys L., using an ecofriendly HPTLC method. Micheloni et al. measure the antioxidant properties of plant extracts using an ecological bioassay (a cupric reducing capacity test) coupled to HPTLC. Likewise, Chaudhary et al. present a HPTLC method for the validation and simultaneous quantification of amino acids and sugars in Eulophia nuda Lindl. corm.

Two papers are devoted to different aspects of characterizing challenging natural product matrices or products derived from their conversion processes. Thus, Böhmdorfer et al. describe a HPTLC method for the direct quantitation of elemental sulfur in pulping liquors, which are spotted (not sprayed) directly onto the plate without prior purification, extraction, or workup. Likewise, Jarne et al. applied automated multiple development by characterizing heavy hydrocarbon-containing products beyond the saturates–aromatics–resins–asphaltenes analysis that is typical in the petroleum industry.

Concerning detection, a new derivatization reagent discriminating reducing from nonreducing saccharides is presented by Schwack et al. As well, a diode-array TLC is described for the quantification of trimethoprim and sulfamethoxazole as a case study by Spangenberg. Furthermore, the aforementioned works by Micheloni et al. and Jarne et al. also deal with bioassay and fluorescence-induced detection, respectively.

Several HPTLC methods applied to pharmaceutical preparations and different biological fluids are also described in this issue. El Gizawy et al. developed a HPTLC–densitometric method for determining three drugs that are used for the treatment of type 2 diabetes mellitus and dyslipidemia. The method was tested in rat plasma. A method is also presented by Duffau et al. for the quali- and quantitative analysis of three synthetic cannabinoids by HPTLC–densitometry in seized samples.

Moreover, Savić et al. performed a study to evaluate the lipophilicity of previously synthesized α,β-unsaturated acids using reversed-phase HPTLC and computational methods, to determine structural and physicochemical parameters affecting the chromatographic behavior of selected compounds.

In addition to thanking the authors of this special issue, on this special event, the co-editors want to congratulate the entire JPC community, which includes readers, authors, referees, advisory and editorial board members, corresponding, managing, and copy editors, and the publishers: Hüthig (1988–89), Research Institute for Medicinal Plants (1990–2006), Akadémiai Kiadó (2007–2019), Akadémiai Kiadó + Springer (2020–).

I would like to make a special mention of Prof. Szabolcs Nyiredy, Editor-in-Chief of JPC, who passed away in 2006, and Prof. Bernd Spangenberg, who served as Editor-in-Chief until 2023. Following his recent retirement, JPC now enters a new stage in which 23 editors (with Dr. Ágnes Móricz as Corresponding Editor) and 16 advisors work collegially. Some of them have recently become editors; others have always been with the journal from the beginning or joined during Prof. Spangenberg’s time and continue to contribute their expertise. The journal has benefited from the scientific experience of the editorial and advisory board members. As it would be somewhat cumbersome to mention each one, let me congratulate each and every one of those who have participated in these roles.

A special mention goes to Mrs. Ágnes Kakuk, who has been serving as Managing Editor from 1998, and Mr. Ian Davies, who had worked as Copy Editor for about 20 years.

I would also like to commemorate those who recently left us. Co-Editor Prof. Teresa Kowalska passed away in 2023, and a special issue of JPC will be dedicated to her in 2024, like the one dedicated to the memory of Prof. Kaiser, who died in 2021.

Co-Editor of this JPC issue