Phosphorus tests

Sawyer JE. Differentiating and understanding the Mehlich 3, Bray and Olsen soil phosphorus tests. Available at http //www.agronext.iastate.edu/soilfertility/ presentations/mbotest.pdf. Accessed June 3,2013. 

Cerium in Plants and Animals. Professor Alfonso Cossa, finding the rare earths of the ceria series to be present in many apatites, and realizing the close association in nature between these earths and calcium and phosphorus, tested for them and detected their presence in bone (66). He also detected them in the ash of barley, beech wood, and tobacco. With the aid of C. Schiapparelli and G. Peroni of the University of Turin, he demonstrated their presence in human urine (66, 67, 68). 

Some colour tests for pesticides are described under Colour Tests, including Nitric-Sulphuric Acid (p. 143) for dicophane. Phosphorus Test (p. 144) for organophosphorus compounds. Sodium Didiionite (p. 144) for diquat and paraquat, and Sulphiuic Acid-Fuming Sulphuric Acid (p. 146) for dielihin, alihin, and endrin. 

Colour Tests. Palladium Chloride—brown Phosphorus Test— yellow. 

Colour Test. Phosphorus Test—yellow precipitate. 

Colour Tests. Palladium Chloride—orange-brown Phosphorus Test—yellow. 

Colour Tests. Palladium Chloride—brown Phosphorus Test— yellow Sodium Nitroprusside (Method 2)—violet. 

El48 Ektachem Phosphorus Test Methodology, M4F026 6-84 (1984). 

According to K. Fischer, the presence of potassium chlorate in match compositions greatly interferes with the testing for phosphorus, and it is advisable to wash the sample several times with cold water to eliminate the chlorate, before distilling. If subsUnces soluble in water are to be determined, the two tests can be comtuned. The washing with water can be avoided by using tartaric acid for the distillation instead of sulphuric acid the presence of potassium chlorate does not then influence the phosphorus test. 

Sims, J.T., Edwards, A.C., Schoumans, O.F. and Simard, R.R. (2000) Integrating soil phosphorus testing Into environmentally based agricultural management practices. Journal of Environmental Quality29, 50-71. 

Silicon Mix approximately 30-50 mg of the plastic sample with 100 mg dry sodium carbonate and 10 mg sodium peroxide in a small platinum or nickel crucible (carefully). Melt it slowly over a flame. After coofing, dissofve the material in a few drops of water, bring it quickly to a boU, and neutralize or slightly acidify it with dilute nitric acid. Add 1 drop of molybdate solution (see phosphorus test), and then heat nearly to boiling. Cool the sample, add 1 drop of benzidine solution (50 mg benzidine dissolved in 10 ml 50% acetic acid add water to make 100 ml), and then add 1 drop of saturated aqueous sodium acetate solution. A blue color indicates silicon. 

---