University of North Florida
Browse the Citations
-OR-

Contact Info

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

View Stuart Chalk's profile on LinkedIn

NRCC DORM-2

Classification: Reference Material -> NRCC -> DORM-2 -> Dogfish muscle

Citations 3

"Temporal And Organ-specific Variability Of Selenium In Marine Organisms From The Eastern Coast Of India"
Adv. Environ. Res. 2001 Volume 5, Issue 2 Pages 167-174
Amit Chatterjee, Badal Bhattacharya and Rajdulal Das

Abstract: Temporal and organ-specific variations of selenium concentration in selected coastal organisms (seagrass, bivalves and fish) were investigated in different biotopes of the deltaic Sundarbans, in the eastern coastal region of India. The bivalves and fish were obtained from local fishermen and were destined for human consumption. The samples were digested with HNO3-H2O2 and selenium was extracted from the aqueous solution with triisooctylamine and stripped with dilute hydrochloric acid. The concentration of selenium was measured by hydride generation-atomic absorption spectrometry. The results obtained were verified using inductively coupled plasma-mass spectrometric and fluorometric methods. The mean selenium concentration found in the various species ranged from 0.05 to 3.94 µg g-1 (dry wt.). It was observed that bivalves accumulated more selenium compared to fish and seagrass. The sequence of selenium levels found was, bivalves > fish > seagrass. In seagrass, the selenium concentration was higher in the roots (0.21±0.03 µg g-1; dry wt.) than the stems (0.17±0.02 µg g-1; dry wt.) and the leaves (0.11±0.01 µg g-1; dry wt.). But, in bivalves, the maximum concentration of selenium was found in the gill (3.94±0.11 µg g-1; dry wt.). The results of the analysis of variance indicated that significant differences in Se concentration were evident between seasons and organs in these species. The variations in uptake of selenium may be due to different metabolic requirements for selenium among the three species, variations in food and differences in interspecies retention and elimination mechanisms.
Selenium Spectrophotometry Method comparison

"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

"Multi-pumping Flow System For The Determination, Solid-phase Extraction And Speciation Analysis Of Iron"
Anal. Chim. Acta 2005 Volume 550, Issue 1-2 Pages 33-39
Carmen Pons, Rafael Forteza and Víctor Cerdà

Abstract: A multi-pumping flow system (MPFS) for the spectrophotometric determination, solid-phase extraction (SPE) and speciation analysis of iron at a wide range of concentrations is proposed. Chelating (iminodiacetic groups) disks have been used as solid phase. A solenoid valve allows the deviation of the flow towards the chelating disk to carry out SPE procedures. The possibility to combine solenoid micro-pumps with solenoid valves increases the versatility of MPFS. Ammonium thiocyanate has been chosen as chromogenic reagent for Fe(III). The determination of total iron is achieved by the on-line oxidation of iron(II) to iron(III) with a hydrogen peroxide stream. A mass calibration was run within the range 0.01-1.75 µg. The detection limit (3sb/S) was 0.01 µg. The repeatability (RSD) was estimated as 1.6% after 10-fold processing of 2 mL of 0.5 mg L-;1 Fe solution. When SPE was not required, two linear calibration graph within the ranges 0.05-10 and 0.2-15 mg L-;1 for the determination of iron(III) and total iron, respectively, were obtained. The proposed procedure was validated by analysis of certified reference materials. The analytical features were compared with those obtained exploiting MSFIA.
Iron(2+) Iron(III) Spectrophotometry Solid phase extraction Chelation Speciation Preconcentration