Measurement of intracellular pH and pCa with a confocal microscope

In the late 1980s, the field of biological confocal microscopy exploded. So did traffic on the Internet. Considering the ongoing interest in the role of intracellular pH and pCa in all aspects of cell physiology, it is not surprising that the most frequently asked question on the Internet's confocal forum has been: 'How do I measure pH/pCa with a confocal microscope?' This article was inspired by these Internet discussions and attempts to answer this question by presenting the rationale for using (or not using) a confocal approach to measure intracellular ion concentration, assessing the feasibility of performing this task with currently prevailing hardware, assembling the currently available 'know-how' and telling 'how'.