Method development for the determination of trace elements in biological samples as bioindicators : application to black spruce trees

• Main Author: Nyade, Praise Kwasi
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2008
• Subjects: Newfoundland
• Online Access: https://research.library.mun.ca/9259/; https://research.library.mun.ca/9259/1/Nyade_Praise.pdf

Most analytical methods, including ICP-MS, require sample decomposition for elemental analysis of plant materials. Dry ashing was investigated in this study. Factors studied included ashing temperature, duration of ashing, rate of temperature rise, and type and nature of ashing vessel on the digestion of plant matrices. The reagents used in the subsequent leaching were also investigated. Samples were ashed at 450°C for 8 hours following a temperature ramp of 18°C/hr, followed by dissolution with HNO₃/HF + H₂O₂. Recovery of silicate elements (Al, Co, Cr, Ni, V, and U) was satisfactory. The procedure was validated with reference materials including pine needles, peach leaves, and black spruce. The result also agreed with that obtained using the wet digestion protocol used by ICP-MS group at MUN. Losses mainly through volatilization were observed for Hg, Se, Br, Bi, I, and As. The dry ashing procedure was applied to a biomonitoring study using black spruce samples from a study area in Holyrood, Newfoundland. The results suggest that the elemental sources include rock weathering, sea spray, atmospheric deposition, the thermal electric plant, vehicular exhaust, and municipal waste leachate.