Phosphorus analysis

Patty Jones, a physical science technician at the NRCS Soil Survey Laboratory, prepares extracts for phosphorus analysis using a diluting device. 

The estabhshed method for phosphorus analysis using a heated block involves a lengthy digestion with sulphuric acid. Furthermore, it is labour and space intensive and requires the digested sample to undergo a second stage for the final analytical determination. 

The phospholipid concentration in a (proteo)liposome suspension can be determined by phosphorus analysis (73) and the protein concentration by automated amino acid analysis or by a calibrated colorimetric protein assay... 

Fundamental principles of chemistry also apply to biochemistry—biological chemistry—and the techniques of neurochemistry have improved since the days of Courbe and his phosphorus analysis. As described in chapters 1 and 2, chemical elements combine in chemical reactions to form compounds. In order for chemical reactions to occur, the reactants—the atoms or molecules participating in the reaction—must meet. 

Phosphorus analysis is usually best accomplished via oxidative acid digestion (H2S04/ HC104) of the samples, followed by colorimetric estimation of the phosphorus as phos-phomolybdovanadate.8... 

Table I. Phosphorus Analysis of Sections of PBSG Films...

Subsequent to recovery of the total lipids of a cellular preparation as a chloroform-soluble fraction, the total phosphorus content can be determined (see Chapter 3) and then, depending on the amount of lipid phosphorus (or whether the preparation is radiolabeled or not, see below), analytical and/or preparative thin-layer chromatography can be undertaken. In either case, if the experimental protocol is centered on a signal-transduction process, then there may be insufficient material for a phosphorus analysis. In the latter instance, the cellular preparation is prelabeled with 32P or [3H]inositol and the labeled products are located by autoradiography. A preferred type of adsorbent (for thin-layer chromatography) is Merck silica gel 60 (oxalate impregnated). An effective solvent for separation of the phosphatidylinosi-tols and other lipids is chloroform-acetone-methanol-acetic acid-water (80 30 26 24 14, v/v). The approximate / values of cellular phospholipids under these conditions are presented as follows ... 

During each analysis, replicates of samples collected in the Genesee River were analyzed as quality-control check samples. The coefficients of variation for total phosphorus analysis of three sediments used as quality-control check samples were 0.12 (n =... 

Typical results for Genesee River watershed bottom sediment phosphorus contents are (phosphorus analysis, x (ug/g), (ug/g), h) total phosphorus, 560, 140, 99 NaOH extractable phosphorus, 58, 62, 98 HCl extractable phosphorus, 398, 99, 98 NH20H extractable phosphorus, 74, 63, 98 (NH )2C204 extractable phosphorus 184, 93, 83. Bottom sediment, suspended sediment, and particulate total phosphorus (560 ug/g, 770 ug/g, and 910 ug/g respectively) Increase as does specific surface area, across these fractions indicating that adsorption processes may be important in increasing sediment phosphorus concentrations. 

Rouser G, Fleisher J, Yamamoto A (1970) Two dimensional thin layer chromatographic separation of plant lipids and determination of phospholipids by phosphorus analysis of spots. Lipids 5 494-496... 

The molybdo-arsenic acid blue colour is usually excluded from the phosphorus analysis by reduction to arsenious acid prior to the addition of ammonium molybdate to form the heteropoly complex. The complex does not form with arsenious radical. Moreover the P can be precipitated with Al(OH)3 and the precipitate treated with HF, HBr, HCl and H2SO4 to volatilize As, Ge and Si which may be co-precipitated leaving P for analysis. 

General Scheme of Phosphorus Analysis. In the analysis of natural waters the measurement of all forms of phosphorus (P) can be divided into two parts (1) a preliminary treatment in which the P form of interest is separated and converted to orthophosphate, and (2) the colorimetric analysis of orthophosphate (usually by the formation of phosphomolybdic acid followed by its reduction with one of a variety of reducing agents to molybdenum blue). The forms of P in natural waters identified in this study are enumerated in Table IV. 

Uses Reagent ion exchange columns photographic additives imparting water resistance in phosphorus analysis as cation-exchanger... 

Phosphorus analysis is usually carried out after perchloric acid digestion (care ) by the method of Bartlett (1959) (Section 6.2.15). Various new methods have been developed more recently, none of which has any distinct advantage over Bartlett s. However, for small samples a mixed acid method has been recommended and this may be used for routine analysis (cf. Cook and Daughton, 1981). 

The most accuracy is obtained when the elution of lipids from tic plates is unnecessary. Glycoglycerolipids can be measured with phenol-H2S04 (Roughan and Batt, 1968, 1969) and phospholipids by organic phosphorus analysis (Rouser et al., 1969). Acyl lipids are also conveniently quantitated from their fatty acid content (see Section VI,C,2), but care should be taken that the transmethylation method used is quantitative for all the lipid classes analyzed. 

Note the absence of phosphoric acid in this sample. This method can also be used to analyse mixtures of alkylether phosphates. The advantage of this method over standard chromatographic procedures is that the phosphorus analysis can be carried out in situ there is no need to extract and subsequently derivatise the surfactants. 

Continuous flow techniques have been widely used for automated phosphorus analysis of waters since the introduction of the segmented continuous flow analysis systems in the 1950s. Segmented continuous flow manifolds described include those which are suitable for the determination of phosphorus in water in the presence of high silica [145], for highly sensitive detection of FRF in the presence of mercuric chloride preservative [146],... 

Bloesch, J. and GavrieUi, J., The influence of filtration on particulate phosphorus analysis, Verhan-dlungen der Internationalen Vereinigungfur Theoretische und Angewandte Limnologie 22,155,1984. 

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