An ion filter and a method of manufacturing an ion filter. The method including providing a monolithic structure; selectively removing regions of the structure, to form a pair of electrodes defining at least one ion channel therebetween. The electrodes are preferably mechanically connected at one or more locations by a portion of the structure; wherein the connecting portion of the structure provides a higher electrical impedance than the filter would provide without such a mechanical connection, to thereby electrically separate the electrodes.