Induced nanoelectrospray ionization for matrix-tolerant and high-throughput mass spectrometry.

No-contact rule: the title method is ultra-sensitive, high-throughput (4 samples per second), easily multiplexed, and is compatible with serum, urine, and concentrated salt solutions. Other features of this method, which avoids physical contact between the electrode and the solvent, include sample economy and the ability to produce both positive and negative-ion spectra in one cycle.