Over recent decades, the development of environmental risks along with their repercussions on health has led to the appearance of a scientific research field of environmental health in which interdisciplinarity is intrinsic to the subject. This article on nonylphenols (NP) shows how exchanges and knowledge transfer involving chemists, biologists, pharmacists and physicians underscore the need to further the development of analytic methodologies in a context involving an ultimate objective likewise subject to constant development. As an example, when an objective consisting in assessment of NP presence in the environment so as to evaluate the quality of natural environments is transformed into an objective consisting in assessment of human exposure to the selfsame NP so as to evaluate risks to human health, it becomes indispensable to redefine the choice of substance of reference to be used. After having spelled out the difficulties encountered when selecting a substance of reference for the analysis of nonylphenols (multiplicity of isomers, variability in the composition of batches for the same CAS Registry Number), 353NP (CAS 186825-36-5) has been proposed as the substance of reference (high proportion in the industrial mixture and pronounced estrogenic power).