Reconditioning of Fused Silica Nanospray Emitters for Electrospray Ionization

Abstract

Stable electrospray generation from fused silica tips is critical for mass spectrometry, but these tips can degrade, leading to droplet formation and poor spray. A quick, cost-effective method has been developed to rejuvenate these tips, extending their usability and reducing expenses. The protocol involves sequentially rinsing pulled fused silica emitters for electrospray ionization (ESI) with acetone, water, an aqueous sodium hydroxide solution, water, and acetone again, followed by air drying. Next, the tip is dipped into a hydroxy-terminated polydimethylsiloxane solution and air dried. A final acetone rinse completes the process, which does not require disassembling the fluidic flow system or removing the nESI tip from its mount. This reconditioning not only prevents droplet formation but also restores the correct spray pattern, ensuring stable electrospray for 1–2 weeks. Tips can undergo multiple reconditionings. Although the protocol may lead to transient contaminant peaks, these diminish over 24 hours, and a list of potential contaminants is provided.