University of North Florida
Browse the Citations

Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

View Stuart Chalk's profile on LinkedIn


Classification: Biological tissue -> muscle -> fish -> dogfish

Citations 3

"Determination Of Total Mercury In Biological Tissues By Flow Injection Cold Vapor Generation Atomic Absorption Spectrometry Following Tetramethylammonium Hydroxide Digestion"
Analyst 1998 Volume 123, Issue 6 Pages 1215-1218
Guanhong Tao, Scott N. Willie and Ralph E. Sturgeon

Abstract: A simple, rapid and reliable method was developed for the determination of total mercury in biological samples. Samples were solubilized by tetramethylammonium hydroxide (TMAH). The organically bound mercury was cleaved and converted to inorganic mercury by online addition of KMnO4. The decomposed mercury together with inorganic mercury originally present in samples was determined by flow injection cold vapor atomic absorption spectrometry after reduction to elemental mercury vapor using NaBH4. A sample throughput of 100 measurements per h was achieved after a 30 min dissolution with TMAH. The relative standard deviation for 20 µg L-1 Hg was 1.3% and the limit of detection was 0.1 µg L-1 (3s). The proposed method was validated by the anal. of a suite of certified marine biological reference materials, DORM-2 (dogfish muscle), DOLT-2 (dogfish liver) and TORT-2 (lobster hepatopancreas), with calibration against simple Hg(II) standards.
Mercury Sample preparation Spectrophotometry Reference material Volatile generation

"Online Preconcentration And Determination Of Mercury In Biological Samples By Flow Injection Vapor Generation Inductively Coupled Plasma Atomic-emission Spectrometry"
Fresenius J. Anal. Chem. 1995 Volume 352, Issue 6 Pages 615-617
Pedro Cañada Rudner, José Manuel Cano Pavón, Amparo García de Torres and Fuensanta Sánchez Rojas

Abstract: Hair was digested with 65% nitric acid for 30 min followed by microwave digestion at 360 W for 4 min and 180 W for 10 min. After cooling for 14 min, the digests were concentrated by evaporation, neutralized with NaOH and diluted with water. Pig kidney and dogfish muscle were prepared by the method of Niazi et al. (Analyst, 1993, 118, 821). The extracts (1.4 ml/min) were mixed with 0.2 M HCl/0.2 M glycine buffer of pH 3.6 (0.4 ml/min) in a FIA system. The flow merged with a stream of 1,5-bis(di-2-pyridyl)methylene thiocarbonohydrazide in IBMK (0.5 ml/min) at a solvent segmentor. The stream passed through an extraction coil (200 cm x 0.5 mm i.d.) to a membrane phase separator and the aqueous phase went to waste. The organic phase filled a sample loop (500 mL volume) and the excess went to waste. The sample was injected into a carrier stream (3.3 ml/min) of IBMF/DMF (1:1) and merged with a reagent stream (0.5 ml/min) of SnCl2 in DMF. The resulting stream passed through a mixing coil (100 cm x 0.8 mm i.d.) for the generation of Hg vapor. The gas and solvent passed to a gas-liquid separator and to Hg vapor was swept to a ICP torch by Ar. The Hg was determined by ICP-AES (operating details tabulated). The calibration graph was linear for 10^-2500 ng/ml of Hg(II) with a detection limit of 4 ng/ml and RSD (n = 10) of 1% at 100 ng/ml. The effects of foreign ions are discussed.
Mercury Sample preparation Spectrophotometry Sample preparation Extraction Preconcentration Interferences Phase separator Volatile generation MIBK Volatile generation

"Comparison Of Sample Digestion Procedures For The Determination Of Arsenic In Certified Marine Samples Using The FI-HG-AAS-technique"
Fresenius J. Anal. Chem. 1997 Volume 357, Issue 7 Pages 817-821
G. Damkröger, M. Grote, E. Janßen

Abstract: For dry ashing, 0.2 g CRM (cod and mussel) were homogenized with 3 g MgO and 40 mL 0.75 M magnesium nitrate, evaporated at 130°C for ~3 h to near-dryness and ashed at 550°C overnight. The ash was dissolved by the dropwise addition of 25 mL 32% HCl and the solutions were diluted to 100 mL with water. For high-pressure ashing, 0.2 g mussel CRM and 0.16 g cod CRM were each mixed with 2 mL 65% HNO3 and 4 mL 30% H2O2 and then ashed with temperature programming from 50-70°C in 30 min, to 120°C in 30 min, then to 300°C (held for 80 min) in 15 min. The resulting clear solutions were diluted to 20 mL with water. For microwave digestion, 0.25 g mussel CRM and 0.2 g cod CRM were each mixed with 3 mL 65% HNO3, and 2 mL 30% H2O2 and irradiated at 250 W for 1 min, left to stand for 1 min, then irradiated at 250 W for 1.5 min, 450 W for 3 min, 850 W for 5 min and 250 W for 1 min. The resulting solutions were diluted to 25 mL with water. The solutions were analyzed for As by flow injection hydride-generation AAS (details given). Mean recoveries of As from mussel and cod were 13% and 2%, respectively, by microwave digestion and 56% and 25%, respectively, by high-pressure ashing. The dry ashing method gave quantitative recoveries from both CRM. Nitrite interference was overcome by the addition of an amino sulfuric acid (350 mM).
Arsenic Sample preparation Sample preparation Sample preparation Spectrophotometry Interferences Method comparison Reference material