“…Besides, the LOD that determined by 3SD (SD is standard deviation) was 0.018 μM (or 3.7 μg L −1 ), which meets the mandated upper limit of 10 μg L −1 and 15 μg L −1 for Pb 2+ in drinking water by the World Health Organization and the U.S. Environmental Protection Agency, respectively. 35 More importantly, the SG-AuNPs probe provided the linear range and LOD value competitive with other colorimetric methods for the analysis of Pb 2+ as listed in Table 2 . Thus, the obtained attainments confirmed an excellent quantification of Pb 2+ at low concentrations assayed by SG-AuNPs.…”