Inner filter effect between upconversion nanoparticles and Fe(ii)–1,10-phenanthroline complex for the detection of Sn(ii) and ascorbic acid (AA)

Dual-function and multi-function sensors can use the same material or detection system to achieve the purpose of detection of two or more substances. Due to their high sensitivity and specificity, dual-function and multi-function sensors have potential applications in many fields. In this article, we designed a dual-function sensor to detect Sn(ii) and ascorbic acid (AA) based on the inner filter effect (IFE) between NaYF(4):Yb,Er@NaYF(4)@PAA (UCNPs@PAA) and Fe(ii)–1,10-phenanthroline complex. Fe(ii)–1,10-phenanthroline complex has strong absorption in most of the ultraviolet-visible light range (350 nm–600 nm), and this absorption band overlaps with the green emission peak of UCNPs@PAA at 540 nm; Fe(ii)–1,10-phenanthroline complex can significantly quench the green light emission of UCNPs@PAA. When Sn(ii) or AA is added to the UCNPs@PAA/Fe(iii)/1,10-phenanthroline, they can reduce Fe(iii) to Fe(ii). Fe(ii) can react with 1,10-phenanthroline to form an orange complex, thereby quenching the green light emission of UCNPs@PAA. And the quenching efficiency is related to the concentration of Sn(ii) and AA; there is a linear relationship between quenching efficiency and the concentration of Sn(ii) and AA, within a certain concentration range the detection limits of this dual-function sensor for Sn(ii) and AA are 1.08 μM and 0.97 μM, respectively. In addition, the dual-function sensor can also detect Sn(ii) and AA in tap and spring water.