High-density Si nanopillars modified with Ag nanoislands: Sensitive SALDI-MS chip for sulfonamides

Abstract

In recent years, the abuse of antibiotics has brought adverse effects on water environment and food safety, to monitor the antibiotic content in water and foodstuffs is imperative for environmental protection and human health. In this work, a chip, composed of high-density Si nanopillars and Ag nanoislands, is prepared for sensitive detection of sulfonamides with surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). In this chip, the high-density Si nanopillars can absorb laser energy efficiently and promote electron transfer as antennas; the Ag nanoislands can enhance the thermal effect; the formation of the Schottky barrier and the conductive nanolayer between Si/Ag can extend the lifetime of electrons and promote electron tunneling effect. Therefore, the heterostructure presents high detection sensitivity (the limit of detection of sulfamethazine is as low as 3 amol); in addition, the satisfactory coefficients of determination (> 0.99) show that the chip is applicable for rapid quantification of sulfonamides. Further, the sulfacetamides spiked in milk and lake water can be sensitively identified and rapidly quantified. The prepared chip presents a considerable potential for food and environment monitoring.