| Abstract: | Calibration standards for quantitative X-ray microanalysis of resin-embedded plant tissue were prepared by adding 6600 mM KC1 to 5% agar. Agar blocks with an edge length of 1–2 mm were rapidly frozen, freeze-dried and embedded in styrene-methacrylate. Dry sections 1 μm thick were mounted on adhesive-coated grids. Apart from fine-scale inhomogeneities caused by ice crystal formation, the KC1 is evenly distributed in the agar blocks. The peak-to-continuum values of K and Cl were highly linearly correlated to the K and Cl contents over the whole concentration range. |
