Ions can be formed under ambient conditions using plasmas, sprays, laser desorption, and photoionization-based approaches. Using an H-bridge circuit driving a transformer optimized to reduce losses, square-wave active capillary DBDI can be continuously powered for ~50 h by common 9 V-battery (PP3).Īmbient ionization methods are recognized for their ability to form intact analyte ions from their in situ environment for detection by mass spectrometry (MS) with high sensitivity in near real time. By use of benzylammonium thermometer ions, the extent of internal energy deposition using square, sine, or triangle waveform excited plasmas are essentially the same at the optimum voltages for ion detection. Protonated dimethyl methylphosphonate (DMMP) and deprotonated perfluorooctanoic acid (PFOA) can be detected at about the same or higher abundances using square-wave DBDI mass spectrometry compared with the use of sine and triangle waveforms. Moreover, the plasma obtained using a square waveform can be significantly more homogenous than that obtained using sine and triangle waveforms. In contrast, the power consumed using a sine and triangle alternating current waveform is more than two orders of magnitude higher than that for the square waveform to obtain a similar voltage for plasma generation. Here, we demonstrate that by using a 10 kHz, ~2.5 kV p-p high-voltage square-wave alternating current plasma, active capillary DBDI can consume less than 1 μW of power.
#Wavesurfer 3024 averaging portable
Active capillary dielectric barrier discharge ionization (DBDI) is emerging as a compact, low-cost, and robust method to form intact ions of small molecules for detection in near real time by portable mass spectrometers.
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