1.1 ,This test method covers the operation, calibration, and data interpretation for an on-line corrosion product (metals) monitoring system. The monitoring system is based on x-ray fluorescence (XRF) analysis of metals contained on membrane filters (for suspended solids) or resin membranes (for ionic solids). Since the XRF detector is sensitive to a range of emission energy, this test method is applicable to simultaneous monitoring of the concentration levels of several metals including titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, mercury, lead, and others in a flowing sample. A detection limit below 1 ppb can be achieved for most metals.