(Royal Society of Chemistry, 2014-09-22)
Alhmoud, Hashim Z; Guinan, Taryn M; Elnathan, Roey; Kobus, Hilton John; Voelcker, Nicolas Hans
Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is ideally suited for the highthroughput
analysis of small molecules in bodily fluids (e.g. saliva, urine, and blood plasma). A key
application for this technique is the testing of drug consumption in the context of workplace, roadside,
athlete sports and anti-addictive drug compliance. Here, we show that vertically-aligned ordered silicon
nanopillar (SiNP) arrays fabricated using nanosphere lithography followed by metal-assisted chemical
etching (MACE) are suitable substrates for the SALDI-MS detection of methadone and small peptides.
Porosity, length and diameter are fabrication parameters that we have explored here in order to optimize
analytical performance. We demonstrate the quantitative analysis of methadone in MilliQ water down to
32 ng mL 1. Finally, the capability of SiNP arrays to facilitate the detection of methadone in clinical
samples is also demonstrated.