A total of 22 substances were identified with confidence level 1 in the 10 municipal water samples, as well as 4 at level 2a, 1 at level 2b, 11 at level 3 and 21 at level 4 (details in Table ). Structural elucidation for MS/MS product ions of compounds identified with level of confidence 2a, 2b and 3 was then attempted; their elemental composition is reported in Table . For compounds with fragmentation pattern not compatible with tentative structures or compounds with chemistries not compatible with extraction selectivity, molecular structural elucidation was attempted manually. Table reports the final list of substances identified with higher confidence levels 1, 2a and 2b along with their experimental or predicted toxicity data and other details including RT, CAS number, molecular formula and m/z. Detection of wellknown and expected compounds showed that the method was effective for reliable targeted analysis. For example, widely reported compounds such as four additional haloacetic acids (three were US EPA-regulated HAAs) and six perfluorinated acids were found in these samples. However, several new or scarcely investigated compounds were also identified showing its added value in NTA. To the best of our knowledge, this is first time dibromethanesulfonic acid was confirmed at confidence Level 1 in drinking water. Previously reported together with other halogenated sulfonic acids in drinking water at confidence level 2b , this substances was present in all samples, but no toxicity data could be retrieved. Dibromomethanesulfonic acid was predicted as both mutagenic and a developmental toxicant, while dichloromethanesulfonic and bromochloromethanesulfonic acid were predicted as developmental toxicant only.