A Simplified Digestion Protocol for the Analysis of Hg in Fish by Cold Vapor Atomic Absorption Spectroscopy

Analysis of mercury in fish is an interesting problem with the potential to motivate students in chemistry laboratory courses. The recommended method for mercury analysis in fish is cold vapor atomic absorption spectroscopy (CVAAS), which requires homogeneous analyte solutions, typically prepared by acid digestion. Previously published digestion protocols require multiple acids, long heating periods or harsh conditions, and reducing agents for workup. We developed a simplified protocol for the digestion of fish that requires only nitric acid and a short heating period. This protocol was successfully implemented in an instrumental analysis lab and enabled students to perform CVAAS on commercial fish samples within the time constraints of an undergraduate lab course.