Integrated liquid chromatography–heated nebulizer microchip for mass spectrometry

Applicability of low‐flow atmospheric pressure chemical ionization and photoionization mass spectrometry with a microfabricated nebulizer for neutral lipids

“…The different shapes of the curves probably reflected diverse volumes and shapes of the regions, where the ionizations take place. The chip tilt of 45° was previously used in micro‐APPI arrangements . For the next measurements, the chip sprayer was positioned on‐axis to ensure optimum spraying for all three operating modes (APCI, APPI, and dual APCI/APPI).…”

“…APCI and APPI with microfluidic chips have been successfully coupled to microliter‐per‐minute HPLC and provided better detection limits when compared to standard commercial high‐flow sources. LC‐microchip APPI‐MS/MS has been used for the analysis of anabolic steroids, pesticides, and aromatic compounds, while the utility of LC‐microchip APCI‐MS/MS has been demonstrated for neurosteroids . To the best of our knowledge, micro‐flow ion sources have never been systematically investigated for their application to neutral lipids, important compounds involved in many fundamental processes in living organisms.…”

High-performance liquid chromatography on glass chips using precisely defined porous polymer monoliths as particle retaining elements

“…In this context the most common bead trapping approach is tapering of the channel to provoke particle stacking either by use of the key stone effect [9] or by creating channel segments smaller than the bead size [10]. A wide range of differently shaped retaining elements was investigated for this purpose such as multi-channel types (frit-like) [3,[11][12][13][14][15][16][17] or a confined single channel appearing in form of a weir [10,18,19], a step [7] or a smooth taper [9,20]. Particulate chromatographic beds in microfluidic devices are generated by slurry packing against these structures.…”

Microfabrication of low thermal mass heated nebulizer chips for mass spectrometry

“…Heated nebulizer chips have been implemented with atmospheric pressure chemical ionization (APCI), atmospheric pressure photoionization (APPI), atmospheric pressure thermospray ionization (APTSI), electrospray ionization (ESI), and desorption atmospheric pressure photoionization (DAPPI) [1]. Heated nebulizer chips have also been combined with liquid chromatography [2], a common separation step, to achieve higher analytical performance.…”