Facile synthesis of magnetic ionic liquids/gold nanoparticles/porous silicon composite SERS substrate for ultra-sensitive detection of arsenic

Abstract Developing a novel and simple route for the synthesis ultrasensitive and specific SERS substrates is highly desirable and technically important. Here, a magnetic ionic liquid (MIL) assisted strategy is developed, and the high-quality and ultra-sensitive MIL-gold nanoparticles/porous silicon (MIL-Au NPs/PSi) composite substrate were synthesized by a fast and cost effective strategy with the assistance of MIL (1-methyl-3-hexyl imidazole ferric tetrachloride ([C6mim]FeCl4). Fundamental SERS performance of this composite substrate was evaluated using rhodamine 6G (R6G). The results showed that MIL make the Au NPs/PSi have great advantages in synergetic enhancement and stability, and the hypersensitive detection of specific substances can be realized by selecting or designing IL. Based on the particularity of MIL ([C6mim] FeCl4′s function and structure, arsenic was detected with MIL-Au NPs/PSi substrate. The detection limit can reach 0.5 ppb, and the standard curves with regression coefficients of 0.98527 and 0.98965 were established in the linear range of 2–80 ppb and 200–800 ppb. In a word, an advanced method for the preparation of high-performance and designable SERS substrate has been developed, which will certainly show promising applications in detection technology.