Chlorinated paraffins (CPs): Analytical conundrums and the pressing need for reliable and relevant standards [30.10.21]
Chlorinated paraffins (CPs) are complex mixtures of polychlorinated, saturaded hydrocarbons considered to be environmentally hazardous and health threatening because of their persistence and high bioaccumulation potential (accumulation in adipose tissue, kidney and liver). They are toxic to aquatic organism and have been proven carcinogen in mouse and rat experiments, hence they are also suspected to be carcinogen for humans. CPS have been detected worldwide in all water bodies, soil, sediments, plants, animals and humans. Innovative laboratory analytics (incl. mass spectrometry and nuclear magnetic resonance) provided significant analytical progress, but reliable and comparable analysis remains a challenge due to the laboratory-dependent variability of results and limitations in commercially available standards. An European consortium including Walter Vetter's group sheds light on various aspects of PC's analytics in three recent publications.
Source: Wikipedia
Original Article
Fernandes, A. R., Vetter, W., Dirks, C., van Mourik, L., Cariou, R., Sprengel, J., Heeb, N., Lentjes, A., & Krätschmer, K. (2022). Determination of chlorinated paraffins (CPs): Analytical conundrums and the pressing need for reliable and relevant standards. Chemosphere, 286, [131878]. doi.org/10.1016/j.chemosphere.2021.131878 
Highlights
• Wide range of CPs (C10–C≤30) are detected, but existing standards have limitations.
• Urgent need for single-chain CP mixture standards for all chain lengths.
• Suitable individual congener (including labelled) standards (C10–C21) are required.
• Homologue-specific mixtures needed for instrument-independent quantitation.
Abstract
The determination of chlorinated paraffins (CPs) has posed an intractable challenge in analytical chemistry for over three decades. The combination of an as yet unspecifiable number (tens - hundreds of thousands) of individual congeners in mass produced commercial CP mixtures and the steric interactions between them, contrive to defy efforts to characterise their residual occurrences in environmental compartments, food and human tissues. However, recent advances in instrumentation (mass spectrometric detectors and nuclear magnetic resonance), combined with interlaboratory studies, have allowed a better insight into the nature of the conundrums. These include the variability of results, even between experienced laboratories when there is insufficient matching between analytical standards and occurrence profiles, the poor (or no) response of some instrumentation to some CP congener configurations (multiple terminal chlorines or < four chlorines) and the occurrence of chlorinated olefins in commercial mixtures. The findings illustrate some limitations in the existing set of commercially available standards. These include cross-contamination of some standards (complex CP mixtures), an insufficient number of single chain standards (existing ones do not fully reflect food/biota occurrences), lack of homologue group standards and unsuitability of some configurationally defined CP congeners/labelled standards (poor instrument response and a smaller likelihood of occurrence in commercial mixtures). They also indicate an underestimation in reported occurrences arising from those CPs that are unresponsive during measurement. A more extensive set of standards is suggested and while this might not be a panacea for accurate CP determination, it would reduce the layers of complexity inherent in the analysis.
Sprengel, J. , Krätschmer, K. , Vetter, W.
A new synthesis approach for the generation of single chain CP mixtures composed of a few major compounds
(2022) Chemosphere
Vetter, W. , Sprengel, J. , Krätschmer, K.
Chlorinated paraffins – A historical consideration including remarks on their complexity
(2022) Chemosphere
