Pigments analysts

Grygar T, Bezdicka P, Hradil D, Domenech A, Marken F, Pikna L, Cepiia G (2002) Voltam-metric analysis of iron pigments. Analyst 127 1100-1107. 

Analysts use reflected light microscopy to examine the surface of polymers. By changing the angle of illumination they can accentuate surface texture and other features of interest. Reflected light microscopy is well suited to the examination of opaque and pigmented samples. Polymer scientists make extensive use of reflected light microscopy when examining the fracture surfaces of failed samples. 

Domenech A, Domenech-Carbo MT, Gimeno JV, Bosch F, Sauri MC, Sanchez S (2001) Electrochemistry of iron oxide pigments (earths) from pictorial microsamples attached to graphite/polyester composite electrodes. Analyst 126 1764-1722. 

The first edition of Food Analysis by HPLC fulfilled a need because no other book was available on all major topics of food compounds for the food analyst or engineer. In this second edition, completely revised chapters on amino acids, peptides, proteins, lipids, carbohydrates, vitamins, organic acids, organic bases, toxins, additives, antibacterials, pesticide residues, brewery products, nitrosamines, and anions and cations contain the most recent information on sample cleanup, derivatization, separation, and detection. New chapters have been added on alcohols, phenolic compounds, pigments, and residues of growth promoters. 

As extensive research into anthocyanin has been conducted over the years, a large amount of information is available on which pigments are found in a particular fruit. This allows an analyst to assess whether a sample contains the expected pigments and to determine whether there are any added from another source or fruit. A very good reference book which details the anthocyanins found in various plants and also gives details of other phenolic materials found in fruits is Macheix s book on plant phenolics (Macheix el al., 1990). 

His published work covered many fields and included diverse subjects such as the chemistry of amino acids and peptides, especially glutathione mineral metabolism, with special reference to calcium melanin pigment metabolism ascorbic acid metabolism metabolic aspects of cardiac muscle and analytical techniques for lipids, nitrogenous compounds, and cortisol. He was an extraordinarily meticulous analyst who, from the first, maintained that the standards of technique in the service laboratory should be the same as those required for research purposes. He maintained that the fulfillment of clinical chemistry demanded equal collaboration between physician and chemist. The function of the latter was not to usurp that of the former but to assist the clinician by helping to shed light on the nature of an illness. 

Compton et al. [18] have worded some (fairly obvious) conditions for the feasibility of a quantitative method (Table 6.4). In developing quantitative methods for polymer/additive analysis Murphy s Law always applies, as also apparent from some of the following Case Studies. Quantitative determinations of new additives should be validated, e.g. by calibration on the basis of more than one mother liquor, repeatability/reproducibility experiments or the use of SPC charts. The analyst must constantly be aware of unwanted interferences. For example, the presence of certain additives, particularly fillers and pigments, may cause serious interferences with the measurement of other additives present [23]. More trivially, contaminations of Chi-massorb 944 residues accumulated in a rotavapour may interfere with subsequent analyses. Care should... 

There have been considerable advances in mass spectrometry in the last 10 years. Advanced techniques such as matrix-assisted laser desorption ionization (MALDI), electrospray ionization (ESI), thermospray ionization, plasma desorption, and ion spray have been improved and are widely used to obtain the mass spectra of polar and nonpolar compounds with the mass of several thousand Daltons. New MS-MS techniques can provide structural information based on fragmentation of selected ions and are of great value both for qualitative and quantitative analyses especially in difficult matrices. There is no method of ionization that is ideal for all samples. Often the analyst and pigment chemist must work togeth-... 

Olby (1966) Olby, J.K. The basic lead carbonates Journal of Inorganic Nuclear Chemistry 28 (1966) 2507-2512 Oliveira et aL (2002) De Oliveira, L.F.C. Edwards, H.G.M. Frost, R.L. Kloprogge, T. Middleton, P.S. Caput mortuum spectroscopic and structural studies of an ancient pigment The Analyst 127 (2002) 536-541... 

The high number of carotenoid pigments in nature (more than 650) and their structural variability make it practically impossible to describe a general methodology for their analysis. Fortunately for the analyst, the number of carotenoid pigments in the food field is relatively small, even though their complexity remains. 

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