NanoSIMS 50: Ion microprobe with multicollection. The 50nm lateral resolution allows intra-cellular analysis of inorganic traces in vegetal or animal tissues. The NanoSIMS isotopic ratio capabilities allow comparison in exactly the same subcellular compartments, of images of the distribution and measurement of the accumulation of several molecules labeled with different stable isotopes (e.g. 15N, 13C, 2H, 18O, 33S, 74Se, ...) or radioactive tracers. Multiple labeling can be used on different or on the same molecules. Multiple Isotope Imaging Mass Spectrometry (MIMS) offers a novel, powerful and quantitative technique for studying intra- and trans-cellular metabolic pathways, signal transduction, cytoplasmic and nucleo-cytoplasmic translocations, RNA and DNA expression and distribution, vesicular and non-vesicular trafficking, virus penetration, and localization of drugs.