Total filterable phosphorus

Maher, W. and L. Woo. 1998. Procedures for the storage and digestion of natural waters for the determination of filterable reactive phosphorus, total filterable phosphorus and total phosphorus. Anal. Chim. Acta 375 5 -7. 

A technique for the extraction of total filterable phosphorus from seawater using iron (ni) hydroxide-coated acrylic fibres was described by Lee et al. (1992). These fibres had previously been shown to adsorb adenosine 5 -triphosphate, DNA, glucose 1-phosphate and glucose 6-phosphate, and were used to preconcentrate large volumes (>1000 1) of seawater. While workers such as Baldwin et al. (1995, 1996) have demonstrated that hydrolysis of organic phosphorus can occur at mineral surfaces, only a small amount of hydrolysis (<3%) was observed in these studies. 

We noted earlier that mass spectrometry had not been used to any extent in speciation studies of organic phosphorus in natural environments. Here we define phosphorus speciation as the determination of actual molecular formulas and structures of molecules containing phosphorus, and not the more commonly accepted, broad classes of phosphorus such as filterable reactive phosphorus, total filterable phosphorus, filterable organic phosphorus, etc. While a few studies have focused on particular classes of organic phosphorus, such as the inositol phosphates, we are not aware of any attempt to broadly speciate... 

The quantitative reliability of inductively coupled plasma high-resolution mass spectrometry for phosphorus determinations was judged by comparing it to the standard total filterable phosphorus method (Gooper et al., 1999). That method includes a persulphate oxidation step to convert all forms of phosphorus to phosphate, which is then suitable for the molybdenum blue reaction. Using the same set of standards, calibration curves for both methods were developed over a range of 0-200 pg P/1. Fig-... 

Eberlein and Kattner [194] described an automated method for the determination of orthophosphate and total dissolved phosphorus in the marine environment. Separate aliquots of filtered seawater samples were used for the determination orthophosphate and total dissolved phosphorus in the concentration range 0.01-5 xg/l phosphorus. The digestion mixture for total dissolved phosphorus consisted of sodium hydroxide (1.5 g), potassium peroxidisulfate (5 g) and boric acid (3 g) dissolved in doubly distilled water (100 ml). Seawater samples (50 ml) were mixed with the digestion reagent, heated under pressure at 115-120 °C for 2 h, cooled, and stored before determination in the autoanalyser system. For total phosphorus, extra ascorbic acid was added to the aerosol water of the autoanalyser manifold before the reagents used for the molybdenum blue reaction were added. For measurement of orthophosphate, a phosphate working reagent composed of sulfuric acid, ammonium molyb-... 

For determination of total P-phosphorus incorporation, filter the precipitate over a glass fiber filter and count for radioactivity. If electrophoresis is intended, collect the precipitate by centrifugation with 5000 X g and dissolve the pellet in the appropriate sample buffer. Choose the electrophoresis system with respect to the different pH stability of phosphorylation products. 

Total Soluble Phosphorus. Total soluble phosphorus includes soluble orthophosphate (soluble condensed phosphate if present) and soluble organic phosphorus. A membrane-filtered sample is treated to release phosphorus as orthophosphate from combination with organic matter and condensed phosphates by some form of oxidation (and hydrolysis). 

Filterable organic phosphorus isolated from several sites in and adjacent to the ENR were analysed by this method, using off-line phosphorus-specific mass spectrometry detection. The organic phosphorus was isolated and concentrated by tangential ultrafiltration and lyophilization to produce concentration factors of —25 and final total organic phosphorus concentrations of —1 mg P/1. Column effluent was collected in 1 ml fractions after ultraviolet detection at 214 nm. The chromatographic fractions, along with a matrix blank and 1 and 10 mg/1... 

This determination on an unfiltered sample yields the amount of total hydrolysable phosphorus (polyphosphate) plus inorganic phosphate in true solution and also the fraction of these ions adsorbed onto particles. The latter fraction is not included when analyses are performed using filtered samples. 

Preliminary sample treatment often involves filtration, which helps to "arbitrarily" separate the particulate and the dissolved phases. Filtration is required to obtain filterable reactive and total filterable reactive phosphorus and is highly recommended at site just... 

In a 1-1. round-bottomed flask are placed 74 g. (0.5 mole) of phthalic anhydride and 30 ml. (0.5 mole) of freshly distilled monoethanolamine. The mixture is heated on a steam bath for 30 minutes the initial reaction is vigorous (Note 1). The reaction mixture is cooled to room temperature, and a reflux condenser is attached to the flask. To the cooled reaction mixture is added slowly, with shaking, 32 ml. (91.3 g., 0.337 mole) of freshly distilled phosphorus tribromide. The reaction flask is then placed on a steam bath and heated under reflux with occasional shaking for 1.25 hours (Note 2). The hot liquid reaction mixture is poured with stirring onto 750 g. of crushed ice. When the ice has melted completely, the crude /3-bromoethylphthali-mide is collected on a Buchner funnel, washed with cold water, and allowed to dry for a few minutes. The crude product (Note 3) is dissolved in 1.2 1. of aqueous ethanol (50% by volume) with the aid of heat. If necessary a small amount of 95% ethanol is added to effect complete solution. The hot solution is filtered and cooled in a refrigerator. A white crystalline product weighing 94-99 g. is obtained. Concentration of the mother liquor to 400 ml. yields an additional 1-3 g. of product. The total yield of product is 95-102 g. (75-80%) m.p. 80-82°. 

The material may be crystallized from boiling methanol (1 ml. per gram of crude material) and forms lustrous, colorless, thick, prismatic needles, which melt with decomposition (Notes 11 and 12). They are separated by suction filtration at 0° and quickly rinsed with a very little ice-cold methanol. The product is hygroscopic and is quickly pressed between filter paper, then dried in a vacuum desiccator over phosphorus pentoxide. The filtrates yield a further crop on partial evaporation under reduced pressure, the total recovery of recrystallized material being 85-90% (Note 13). 

Phenylethyl Iodide. Use 146 g. (142 ml.) of (J-phenylethyl alcohol (b.p. 216 5-217°), 16 54 g. of purified red phosphorus and 154 g. of iodine. Lag the arm C (Fig.///, 40, 1) with asbestos cloth. Heat the alcohol - phosphorus mixture to boiling until sufficient alcohol (usually one-third to one-half of the total volume) passes into the reservoir B to dissolve all the iodine. Remove the flame and add the iodine solution at such a rate that the mixture boils gently. A little hydrogen iodide is evolved towards the end of the reaction. Allow the mixture to cool, add water and filter off the excess of phosphorus. Decolourise the filtrate with a little sodium bisulphite and add ether to assist in the separation of the water layer. Wash the ethereal solution with water, dry with anhydrous potassium carbonate, and distil under diminished pressure. B.p. 114 116°/12 mm. Yield 215 g. 

Schwer and Clausen (1989) reported that a fescue/ryegrass/bluegrass filter strip retained 89% of the phosphorus from dairy milk-house wastewater. Vought et al. (1994), summarizing his own research on phosphorus removal from surface runoff, noted exponential removal with 66% and 95% of soluble phosphorus retained in the first 8 and 16m of buffer strip, respectively. Daniels and Gilliam (1996) determined that fescue and riparian filter strips reduced total phosphorus load by 50%, but that 80% of the soluble phosphorus frequently moved through the strips. 

If a water sample contains both soluble and insoluble manganese (Mn) compounds and ions, and it is filtered to separate the dissolved and insoluble fractions, and the filtrate and insoluble residue are analyzed separately, the results can be expressed as total dissolved Mn and total suspended or insoluble Mn. Phosphorus (P) can be determined colorimet-rically as the ortho-phosphate ion, P043, in aqueous samples after a reaction that forms an intensely blue-colored derivative. However polyphosphate ions and other ions and compounds containing P do not form this derivative. Total P in a sample can be determined with the same colorimetric procedure after acid hydrolysis and oxidation of all ions and compounds containing P to P04 3. In some elemental analyses the sample is treated with reagents designed to make available for measurement some fraction of an element or elements but not the total amount. For example, a soil sample may be treated with water at pH 3 to simulate the leaching process of acid rain. A total elemental analysis of the filtrate provides information about just those elements solubilized by the mild acid treatment. This can be called the determination of total mild acid leachable elements. 

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