The Pb ion selective electrode should, in principle be one of the most easy methods for measurements of Pb. However the electrode is very sensitive to pH and background solution composition. In the best of worlds the pH would be monitored and adjusted every step of the way in the calibration curve. Read the materials to see why pH is so problematic and try working though an excel exercise calibration curve.

Fun fact: the lead ion selective electrode has silver in it. The Romans mined silver containing lead for silver and contaminated the Arctic ice in so doing.

Macroscopic lead sulfide has a dark color.  When the size of the crystal begins to approach the wavelength of visible light (~390-750 nm), the perceived color of the particle changes.  This is an image of a compact assembly of lead-sulfide nanoparticles interacting to create a “petalled blossom”.  The image, entitled “Field of Flowers”, was captured by Paul Podisadlo and Elena Shevchenko of Argonne National Laboratory, Argonne, IL.   Source: Used with the permission of the laboratories.