NORMAN guidance on suspect and non-target screening in environmental monitoring

Abstract

Increasing production and use of chemicals and awareness of their impact on ecosystems and humans has led to large interest for broadening the knowledge on the chemical status of the environment and human health by suspect and non-target screening (NTS). To facilitate effective implementation of NTS in scientific, commercial and governmental laboratories, as well as acceptance by managers, regulators and risk assessors, more harmonisation in NTS is required. To address this, NORMAN Association members involved in NTS activities have prepared this guidance document, based on the current state of knowledge. The document is intended to provide guidance on performing high quality NTS studies and data interpretation while increasing awareness of the promise but also pitfalls and challenges associated with these techniques. Guidance is provided for all steps; from sampling and sample preparation to analysis by chromatography (liquid and gas—LC and GC) coupled via various ionisation techniques to high-resolution tandem mass spectrometry (HRMS/MS), through to data evaluation and reporting in the context of NTS. Although most experience within the NORMAN network still involves water analysis of polar compounds using LC–HRMS/MS, other matrices (sediment, soil, biota, dust, air) and instrumentation (GC, ion mobility) are covered, reflecting the rapid development and extension of the field. Due to the ongoing developments, the different questions addressed with NTS and manifold techniques in use, NORMAN members feel that no standard operation process can be provided at this stage. However, appropriate analytical methods, data processing techniques and databases commonly compiled in NTS workflows are introduced, their limitations are discussed and recommendations for different cases are provided. Proper quality assurance, quantification without reference standards and reporting results with clear confidence of identification assignment complete the guidance together with a glossary of definitions. The NORMAN community greatly supports the sharing of experiences and data via open science and hopes that this guideline supports this effort.

Tracking Dynamic Chemical Reactivity Networks with High-Resolution Mass Spectrometry: A Case of Microplastic-Derived Dissolved Organic Carbon

“…Unequivocal molecular formulas were obtained for 1324 and 2244 features for TPU_Ester and TPU_Ether, respectively. In 80% of the cases, the monoisotopic mass of an ionized formula deviated from the m / z value of the feature it was assigned to by ±3 ppm or better, which is in line with the expected performance of commercially available HRMS instruments in small molecule screenings . Histograms showing the distribution of the mass error of all annotated formulas are provided in the SI (Section S6, Figure S6.2).…”

“…In 80% of the cases, the monoisotopic mass of an ionized formula deviated from the m/z value of the feature it was assigned to by ±3 ppm or better, which is in line with the expected performance of commercially available HRMS instruments in small molecule screenings. 69 bution of the mass error of all annotated formulas are provided in the SI (Section S6, Figure S6.2). Using these data, the chemical character of the MP-DOC was visualized in VK space (H/C versus O/C), as is commonly done with complex mixtures of organic matter (Figure 2).…”

Online and Offline Prioritization of Chemicals of Interest in Suspect Screening and Non-targeted Screening with High-Resolution Mass Spectrometry

“…However, pooled quality control samples can be used to generate an inclusion list without requiring multiple injections of every sample. 57 Triggering strategies can also involve the real-time determination of the isotopic abundance pattern; for example, chemicals containing Cl and Br can be triggered for MS 2 based on the increased intensity of the [A + 2] + isotope caused by their naturally occurring stable isotopes (Figure 2c). Similarly, the presence of adduct formations ([M + H] + , [M + Na] + , [M + K] + , etc.)…”

“…These approaches require multiple injections and data analysis that will increase the total user time for acquisition. However, pooled quality control samples can be used to generate an inclusion list without requiring multiple injections of every sample …”

Quantitative Nontarget Analysis of CECs in Environmental Samples Can Be Improved by Considering All Mass Adducts

“…For the success of the prediction, the appropriate transferability is as important as the error of the model itself. The transferability investigation of NTA data is a general shortfall, also in recent NTA guidelines, , although it is essential for harmonization and retrospective data analysis . Existing models typically generalize the transferability by using a linear correction factor, , which is a compromise that is relatively simple to implement but does not account for the changes in individual compounds with different properties .…”