Pigments, analysis

Shack, D., Engel, U., and Reznik, H., High performance liquid chromatography of hetalains and its application to pigment analysis in Aizoaceae und Cactaceae, Ztschr. PflanzenphysioL, 101, 215, 1981. 

Wrolstad, R.E. et al., Use of anthocyanin pigment analysis for detecting adulteration in fruit juices, in Methods to Detect Adulteration in Fruit Juice and Beverages, Vol. 

PIXE has also been used for pigment analysis in furniture and interior painting [301a], The growing use of piPIXE and associated beam techniques in art and archaeometry is noticeable [302,303], Even delicate materials such as paper and parchment are unaffected by microbeams. 

Recent ultrasedimentation techniques for pigment analysis have abandoned the two-layer principle. Measurements can now be taken directly on the aqueous dispersion itself, which alleviates a number of problems, such as the streaming effect. However, both the intricate instrumentation and the complex mathematical evalu-... 

Numerous CE separations have been published for synthetic colours, sweeteners and preservatives (Frazier et al., 2000a Sadecka and Polonsky, 2000 Frazier et al., 2000b). A rapid CZE separation with diode array detection for six common synthetic food dyes in beverages, jellies and symps was described by Perez-Urquiza and Beltran (2000). Kuo et al. (1998) separated eight colours within 10 minutes using a pH 9.5 borax-NaOH buffer containing 5 mM /3-cyclodextrin. This latter method was suitable for separation of synthetic food colours in ice-cream bars and fmit soda drinks with very limited sample preparation. However the procedure was not validated for quantitative analysis. A review of natural colours and pigments analysis was made by Watanabe and Terabe (2000). Da Costa et al. (2000) reviewed the analysis of anthocyanin colours by CE and HPLC but concluded that the latter technique is more robust and applicable to complex sample types. Caramel type IV in soft drinks was identified and quantified by CE (Royle et al., 1998). 

Chlorophylls and other pigments have been frequently investigated in marine samples. As the amount of chlorophyll may be used as a marker for phytoplankton production its determination is of paramount importance in sea research [274], HPLC data have been used for the study of phytoplankton community structure [275] and for the indentification of phytoplankton groups [276], Earlier advances in HPLC pigment analysis have been reviewed [277],... 

Gel filtration chromatography carried out on a Sephadex stationary phase has also been employed for pigment analysis. The decolourization of molasses spent wash (MSW) by the white-rot fungus Flavodon flavus was followed with this technique. Untreated and treated MSW samples were diluted up 10 per cent and were loaded into a Sephadex G-50... 

S.W. Jeffrey, S.W. Wright and M. Zapata, Recent advances in HPLC pigment analysis of phytoplankton. Marine Freshwat. Res. 50 (1999) 879-896. 

C.K. Wong and C.K. Wong, HPLC pigment analysis of marine phytoplankton during a red tide occurrence in Tolo Habour, Hong Kong. Chemosphere 52 (2003) 1633-1640. 

M. Estrada, P. Henriksen, J.M. Gasol, E.O. Casamayor and C. Pedros-Alio, Diversity of planktonic photoautotrophic microorganisms along a salinity gradient as depicted by microscopy, flow cytometry, pigment analysis and DNA-based methods. FEMS Microbiol. Ecol. 49 (2004) 281-293. 

Cells are typically concentrated by filtration and extracted into an organic solvent (usually acetone) after which, pigments are detected by fluorescence or absorption spectroscopy, sometimes after chromatographic separation (Bidigare and Trees, 2000). The application of HPLC to phytoplankton pigment analysis has lowered the uncertainty in the measurement of Chi a and accessory carotenoids, since compounds are physically separated and individually quantified. 

Lange B, Scholz F, Weuiss A, Schwedt G, Behnert J, Raezke KP (1993) Abrasive stripping voltammetry - the electrochemical alternative for pigment analysis. Internal Lab 23 23-26. Scholz F, Nitschke L, Henrion G (1989) Identification of solid materials with a new electrochemical technique - the abrasive stripping voltammetry. Fresenius Z Anal Chem 334 56-58. 

BChl a in solution ( 660 + 10 mV).66 ENDOR/TRIPLE further showed that the spin is completely localized on one BChl half (Fig. 3). The pigment analysis showed that the RC contains 3 BChl and 3 BPh, whereas 4 BChl and two BPh are found in wild type. On the basis of earlier work5467 it is therefore assumed that in these mutants, a BChl-BPh heterodimer is the primary donor. Since BPh has a higher redox potential than BChl,66 only the BChl half is oxidized and carries the spin and positive charge. This situation is energetically less favorable than delocalization in a dimeric species, which leads to the observed increase of P 865. For the heterodimer mutants, a lower quantum yield and reduced ET rates have been observed. The experiments clearly show that dimer formation alone significantly lowers and, thereby, adjusts the donor s oxidation potential.68... 

Wrolstad, R.E., Hong, V., Boyles, M.J., and Durst, R.W. 1995. Use of anthocyanin pigment analysis for detecting adulteration in fruit juices. In Methods to Detect Adulteration in Fruit Juice and Beverages, Vol. I (S. Nagy and R.L. Wade, ed.). AgScience Inc., Auburndale, Fla. 

Schwartz, S.J. 1998. Pigment analysis. In Food Analysis (S.S. Nielson, ed.). Chapman and Hall, Gaitherburg, Md. 

Schmid, H., Bauer, F., and Stich, H.B. (1998) Determination of algal biomass with HPLC pigment analysis from lakes of different trophic state in comparison to microscopically measured biomass. J. Plankton Res. 20, 1651-1661. 

Visser for pigment analysis and technical support. We thank Walker Smith for a critical review of the manuscript. MAvL and JS were financially supported by the Dutch Polar Programme of the Research Council for Earth and Life Sciences (ALW) of the Netherlands Organisation for Scientific Research (NWO). 

Suzuki K, Hinuma A, Saito H, Kiyosawa H, Liu H, Saino T et al (2005) Response of phytoplankton and heterotrophic bacteria in the northwest subarctic Pacific to in situ iron fertilization as estimated by HPLC pigment analysis and flow cytometry. Prog Oceanogr. DOI 10.1016/j.po-cean.2005.02.007... 

Hong Y, Smith WO, White A-M (1997) Studies on transparent exopolymer particles, (TEP) produced in the Ross Sea (Antarctica) and by Phaeocystis antarctica (Prymnesiophyceae). J Phycol 33 368-376 Irigoien X, Meyer B, Harris R, Harbour D (2004) Using HPLC pigment analysis to investigate phytoplankton taxonomy the importance of knowing your species. Helgol Mar Res 58 77-82... 

The analyses were performed at The Henry Francis du Pont Winterthur Museum on a Kevex 4525P energy dispersive XRF spectrometer low-level radioactive isotopes were used for the incident radiation (4). The pigment area analyzed was successively irradiated by an iron-55 source, an americium-241 source, and a cadmium-109 source. A qualitative pigment analysis takes only 6 min. Neither the coloring matter nor the silk fabric is altered in any way by the measurement. Figure 8 shows our XRF system setup for the analysis of pigments on painted and printed silks. 

Figure 9. The Henry Francis du Pont Winterthur Museum s analytical laboratory and conservation staff preparing an 18th century painted silk gown for pigment analysis. (Acc. No. 42-33-2, Philadelphia Museum of Art courtesy of The Henry Francis du Pont Winterthur Museum.)...

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