Applying secondary ion mass spectrometry to the analysis of elements in globlet cells of conjunctiva

We investigated the location of elements in the goblet cells of rat conjunc tiva by analyzing ion images produced by secondary ion mass spectrometry (S IMS) and comparing them with those produced by energy dispersive Xray analy ser (EDX). Conjunctivas of normal Spraque-Dawley rats were quenched in prop ane prechilled liquid nitrogen. Semi-thin sections were made with a cryo-ul tramicrotome, freeze-dried, carbon-coated and observed under a light micros cope, SIMS and scanning electron microscope (SEM). In the element analysis by SIMS, images of positive ions were examined with an O2+ primary ion sour ce and images of negative ions with a Ga+ ion source. The same sections wer e observed and analysed with SEM-EDX. Morphological features and images of elements with SIMS and EDX were compared. Na, Mg, K, and Ca were detected a s positive ions and OH, CN, P, S, and Cl as negative ions with SIMS, but C, N, O, Na, Mg, P, S, Cl, K, and Ca were detected with EDX. The spatial reso lution of SIMS in element location was higher than that of EDX. Many elemen ts were clearly located in the goblet cells on ion images by SIMS. Element ion images were demonstrated more densely in goblet cells than in other par ts within conjunctiva and by SIMS compared to EDX. SIMS is a useful method for the detection of elements and their locations in ocular tissues and cel ls.