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

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Classification: Reference Material -> NIES -> 3 -> Chlorella

Citations 4

"Determination Of Phosphorus In Turbid Waters Using Alkaline Potassium Peroxodisulphate Digestion"
Anal. Chim. Acta 1995 Volume 315, Issue 1-2 Pages 123-135
L. Woo and W. Maher*

Abstract: The evaluation of the use of alkaline peroxodisulphate digestion with autoclaving or microwave heating for the determination of total phosphorus in turbid lake and river water is described. Procedures were evaluated by the analysis of suspensions (20, 50 and 100 g P/l) of two standard reference materials, National Institute of Environmental Science, Japan No. 3 Chlorella and No. 2 Pond Sediment. Suspensions were prepared by adding these materials to distilled deionized water (pH 6) and homogenisation using shaking, sonification and stirring. Best recoveries of phosphorus were found when the final solution was 0.045 M in potassium peroxodisulphate and 0.04 M in sodium hydroxide and solutions digested in an autoclave at 120°C for 60 min. or heated in a microwave oven at 450 W for 10 min. Complete recoveries of phosphorus (99-103%) from 20, 50 and 100 g P/l Chlorella suspensions were obtained using both autoclave and microwave heating. For the Pond Sediment complete recoveries of phosphorus (99-107%) from the 20 and 50 g P/l suspensions were obtained using both heating methods. Higher recoveries from the 100 g P/l Pond Sediment suspensions were obtained using microwave heating (96 ± 1%) than autoclaving (88 ± 5%). Recoveries of phosphorus compounds (phosphates, and phosphonates) added to distilled deionized water and turbid lake water were near quantitative (91-117%) for both digestion procedures. Further analysis of Pond Sediment suspensions showed that complete recovery of phosphorus (98 ± 1%) from 60 g/l suspensions was achieved with incomplete recoveries (92.3 ± 0.7%, 91 ± 2% and 91 ± 1%) from 70 g P/l, 80 g P/l and 90 g P/l suspensions respectively. Comparison with the APHA-AWWA WPCF, nitric-sulphuric acid digestion method showed no difference in phosphorus measurements for the microwave procedure but that the autoclave procedure gave significantly lower recoveries of phosphorus (p < 0.01), however, differences were only 2-8%.
Phosphorus Sample preparation Sample preparation Reference material Method comparison

"Online Microwave Digestion Of Slurry Samples With Direct Flame Atomic Absorption Spectrometric Elemental Detection"
Analyst 1992 Volume 117, Issue 2 Pages 117-120
Stephen J. Haswell and David Barclay

Abstract: A flow injection system is described (with diagram) for online microwave digestion of slurried samples and AAS detection. Sample slurries were prepared in 5% HNO3 and portions (1 ml) were injected into the system and passed through a PTFE coil (20 m x 0.8 mm i.d.) in a microwave oven operated at 90% power (525 W). The digest was passed through a 5-m cooling loop in an antifreeze bath and then through a back-pressure regulator to the nebulizer of an AAS instrument. Recoveries of Mg, Ca, Zn and Fe from reference materials were 93.6 to 107%. Precision was 4 to 5%. A flow injection (FI) system for online microwave digestion of slurried samples with direct elemental determinations by flame atomic absorption spectrometry is described. Organic based elemental reference samples were prepared as slurries in 5% (by volume) HNO3 and the system was optimized for slurry mass, acid strength and tube and microwave cavity geometry. Bubble formation during digestion was controlled by post-digestion cooling and pressure regulation. Comparison of direct and FI calibrations indicated no apparent loss in sensitivity. Various samples (e.g. chlorella, mussel, sargasso, pepperbush, bovine liver reference materials) were examined and elemental recoveries for Ca, Fe, Mg, and Zn were typically found to be in the range 94-107% with precisions of less than 4.5% relative standard deviation. The major source of error was found to be in the dispersion of solids (<180 µm) as slurries in dilute HNO3. The throughput of samples in the system developed was 1-2 min per sample.
Magnesium Calcium Zinc Iron Sample preparation Spectrophotometry Microwave Online digestion Slurry Reference material

"Simultaneous Determination Of Silicon And Phosphorus In Biological Standard Materials With Online-column Flow Injection Spectrophotometry"
Fresenius J. Anal. Chem. 1988 Volume 332, Issue 2 Pages 162-166
Yoshio Narusawa, Tsutomu Katsura and Fuki Kato

Abstract: Biological standard material (1 g), viz, NIES chlorella or pepperbush or NBS bovine liver, was ashed, the ash was fused with Li2CO3 - H3BO3 for 15 min at ~1000°C, and the cooled melt was dissolved in and diluted to 100 mL with 1 M HCl. A 2.5 mL portion of extract was diluted with water (2.5 ml) and the mixture was cleaned up by cation exchange on a column (3 cm x 8 mm) of Dowex 50W-X8 (100 to 200 mesh) pre-conditioned with 2 M HCl (10 ml) and water (2 x 10 ml). Elution was effected with 0.5 M HCl (5 x 2 ml), the combined eluates were evaporated to dryness, 0.5 mL of 0.25 M Na2CO3 was added and, after evaporation to dryness, the residue was fused at ~1000°C for 15 min. The melt was dissolved in water containing 0.01 M EDTA (1 ml) and the solution was diluted to 25 mL with water. Phosphorus and Si were then determined by flow injection analysis as previously described (Anal. Abstr., 1988, 50, 8B123) with online anion-exchange separation on a column (15 cm x 4.6 mm) of TSK-gel SAX (5 µm). Most commonly occuring ions, e.g., Ca and Mg, were removed on the cation-exchange column; however, arsenate and germanate were not. Results agreed with those by ICP-AES.
Silicon Phosphorus Ion exchange Spectrophotometry Merging zones Method comparison Simultaneous analysis Reference material

"Determination Of Manganese By Flow Injection Analysis Based On Its Catalytic Effect On The Oxidative Coupling Reaction Of 3-methyl-2-benzothiazolinone Hydrazone With NN-dimethylaniline"
Anal. Sci. 1991 Volume 7, Issue 1 Pages 97-101

Abstract: Sample solution was injected into a carrier stream of aqueous 1.2% H2O2 and reacted at 50°C in a reaction coil (3 m) with 0.1 M citrate - 0.2 M Tris buffer solution (pH 11), 30 mM NN-dimethylaniline - 3 mM 3-methyl-2-benzothiazolinone hydrazone - 3 mM 1,10-phenanthroline. The mixture was cooled to 25°C in a 1-m reaction coil and the absorbance was measured at 590 nm. The calibration graph was rectilinear for 4 to 30 ng mL-1 of Mn and the coefficient of variation were 1.9 to 4.2%. The method was applied in the analysis of standard reference materials, the results obtained compared well with certified values.
Manganese Spectrophotometry Buffer Catalysis Heated reaction Reference material