downstream from the back of the channel field 25 closest to first inlet window 56 both filter elements 71 and serpentine channels 75 function to separately trap debris and other particles in the liquid sample liquid sample introduced to nozzle structure 50 through first inlet window 56 travels through associated filter elements 71 downstream through serpentine channels 75 and ultimately out through a substantially rectangularly shaped orifice at tip channel 78 extending axially through microcapillary tip 80 liquid sample introduced to nozzle structure 50 through second inlet window 57 bypasses filtration through the serpentine channels 75 it should be appreciated that while serpentine channels and filter elements have been shown as a manner to provide filtration other orientations are possible for example the nozzle structure 50 may be fabricated with only serpentine channels or only with filter elements and such may be of variable dimensions and sizes an important consideration in designing the positioning of filtration means is selecting appropriate spacing and dimensioning so as to achieve sufficient filtration clogging between the nozzle structure parylene layers by particulates in the liquid sample also must be considered use of more than one sample inlet window 56 57 facilitates mixing or adding other liquids to the sample before ionization fig3 a to 3f will now be used to explain the fabrication steps associated with the formation of a polymer based nozzle structure fig3 a to 3f only show a limited cross section of the nozzle structure 50 of fig2 taken along zigzag path a a u2032 the nozzle structure 50 is generally similar in fabrication to the u201c sandwich u201d layering of the silica based nozzle.