SCANNING ELECTRON-MICROSCOPY WITH ENERGY-DISPERSIVE ELECTRON-PROBE X-RAY-ANALYSIS INVESTIGATION OF A SEQUENTIAL EXTRACTION SCHEME FOR COPPER, CHROMIUM, IRON AND ALUMINUM SPECIATION IN MARINE SUSPENDED PARTICULATE MATTER

In a wider context of solid speciation studies and with a view to futu re application to real marine suspended particulate matter, a sequenti al chemical extraction procedure was tested on a plankton reference st andard and checked with scanning electron microscopy with energy-dispe rsive electron probe X-ray analysis, and with atomic absorption and em ission spectroscopic techniques. The results indicate that the procedu re has a limited efficiency and needs further improvement. To increase the accuracy of the entire procedure, some steps, such as separation of the particulate matter from the filter and weighing of the particul ate, have been optimized.