Aminoplastic standards for quantitative X-ray microanalysis of thin sections of plastic-embedded biological material.

The preparation of a set of aminoplastic standards for quantitation of sodium, magnesium, phosphorus, sulfur, chlorine, potassium, and calcium in ultrathin plastic sections of soft tissue is described. The standards are low in cost and easy to prepare and handle. They cover concentrations up to 750 mmoles/kg dry weight, and display chemical and physical properties similar to those plastic-embedded samples. The standards can be used to convert peak-to-continuum ratios obtained from the specimen to elemental concentrations. An application of these standards is shown using rat exocrine pancreas as a model. The standards can also be used to advantage for the calibration of the detector efficiency.