A bibliometric analysis of global research hotspots and progress on emerging environmental pollutants 6PPD and 6PPD-quinone from 2004 to 2024

The emerging toxicants, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q), resulting from environmental exposure to N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), have gained considerable attention owing to their ubiquitous occurrence and high toxicity. We performed a scientometric analysis on this topical area of research over the past two decades, spanning from 2004 to April 2024. The overarching aim was to reveal potential future directions in this research area, exploring several key aspects. These included publication and citation growth trends, relevant subject fields, distribution of contribution by country, influential journals in the field, keyword co-occurrence network and cluster analysis, and identification of top authors. The information was collected from the Scopus database and processed using the VOS viewer software. We observed a notable increase in the number of publications over the past four years. With a share of 46.2% of publications, "Environmental Sciences" dominated as the primary scientific category. Among all journals, "Science of the Total Environment" was the most prolific, publishing 33 documents, accounting for 15.6% of the total records. China, representing 76 publications (36%), followed by the United States, with 40 (18.9%), stood out as the leading countries. The occurrence of keywords such as "Pollution exposure", "Mass spectrometry", and "toxicity" highlighted the importance of assessing the toxicological properties, analytical methods, and environmental implications of these emerging contaminants to mitigate their adverse effects and protect environmental and human health. Cai, Zongwei from Hong Kong Baptist University was highly productive in this field, publishing 11 papers. Based on the bibliometric analysis presented, it seems that the future direction of research on 6PPD and 6PPD-Q will shift towards strategies focused on their removal and treatment.