Colorimetric determination of phosphorus in steel and cast iron

Abstract

A colorimetric meth od is described for the determination of phosphorus in steels and irons. The phosphomolybdenum blue reaction is utilized, and the transmittancy of the colored solution is measured with a photoelectric colorimeter and a Corning Lantern Shade Yellow filter, No. 349. Provision is made for the effects of arsenic and silicon, and a method of compensating for the color of alloying constituents is given. An accuracy of ± 0.003 percent was indicated for steels whose phosphorus content ranged from 0.01 to 0.11 percent. With cast irons containing 0.25 to 0.80 p ercent of phosphorus, values accurate to ± 0.02 percent were obtained. A single determination of phosphorus in steel can be made in about 20 minutes, and a set of eight determinations can be completed in approximately 45 minutes.

Apparent molar heat capacities of phospholipids in aqueous dispersion. Effects of chain length and head group structure

“…In some cases, i.e., with DMPC and DPPC, higher concentrations (2-4 mg-mL"1) were also tested. The exact phospholipid concentration was determined after the calorimetric runs from the original sample by using a modified procedure for phosphate analysis (Hague & Bright, 1941). Concentration determinations from separate aliquots of the sample varied in general within ±0.8% except for PEs where due to the coarseness of the dispersions, variations were somewhat greater 1 Abbreviations: *CP, apparent molar heat capacity: DSC, differential scanning calorimetry; TLC, thin-layer chromatography; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PA, phosphatidic acid; LPC, 1-paimitoyllysolecithin; DMPC, dimyristoylphosphatidylcholine; DPPC, dipalmitoylphosphatidylcholine; DSPC, distearoylphosphatidylcholine; DAPC, diarachidoylphosphatidylcholine; DLPE, dilauroylphosphatidylethanolamine; DMPE, dimyristoylphosphatidylethanolamine; DPPE, dipalmitoylphosphatidylethanolamine; DSPE, distearoylphosphatidylethanolamine; DAPE, diarachidoylphosphatidylethanolamine; DMPA, dimyristoylphosphatidic acid; DPPA, dipalmitoylphosphatidic acid; DTPA, ditetradecylphosphatidic acid; DHPC, dihexadecylphosphatidylcholine; DHPE, dihexadecylphosphatidylethanolamine; DHPA, dihexadecylphosphatidic acid; 7m.…”

Calorimetric and fluorescence depolarization studies on the lipid phase transition of bacteriorhodopsin-dimyristoylphosphatidylcholine vesicles

“…The results were corrected for a systematic error in the case of BR (Rehorek & Heyn, 1979). Phospholipid concentrations were determined by phosphorus analysis according to Ames & Dubin (1960) or by following a modified procedure of Hague & Bright (1941).…”

Standard Reference Materials :

“…(c) Cover the boat and proceed as described above, More rapid and sensitive photometric methods which utilize the molybdenum-blue reaction are generally preferred because of their relative freedom from interferences by alloying elements [7].…”