Phosphate in urine

Several investigators have described the indirect determination of orthophosphate by extraction of the phosphomolybdic acid complex and the measuring the molybdenum extracted. Zaugg and Knox 2921 first applied this technique to the determination of phosphate in urine. A protein-free filtrate was formed and the complex was extracted into 2-octanol. More recently, Devoto 293) determined 0 to 25 pg of phosphate in 50 ml of urine by extracting the complex from acidified urine into isobutyl acetate. 

Brokopp CD, Wyatt JL, Gabica J. 1981. Dialkyl phosphates in urine samples from pesticide formulators exposed to disulfoton and phorate. Bull Environ Contam Toxicol 26 524-529. 

Mechanism of Action An antacid that reduces gastric acid by binding with phosphate in the intestine, and then is excreted as aluminum carbonate in feces. Aluminum carbonate may increase the absorption of calcium due to decreased serum phosphate levels. The drug also has astringent and adsorbent properties. Therapeutic Effect Neutralizes or increases gastric pH reduces phosphates in urine, preventing formation of phosphate urinary stones reduces serum phosphate levels decreases fluidity of stools. 

Urinary phosphate was measured in eight human cases of dermal white phosphoms bum following explosion of incendiary munitions. It was not possible to estimate doses. The rate of urinary phosphate excretion varied widely, ranging between 0.08 and 5.83 g/day. The normal adult human output of inorganic phosphate in urine is 0.34—1.0 g/day (Henry 1967). 

A similar method is used for the determination of inorganic phosphates in urine. 1 to 5 c.e. of the urine, containing about 0-5 milligram of phosphorus, are diluted and treated with a solution of ammonium molybdate in 15 per cent, sulphuric acid (5 c.c.), 1 c.c. of 1 per cent, hydroquinone solution and 1 c.c. of 20 per cent, sodium sulphite solution. The blue colour is compared in Nessler glasses with that developed by the same solutions when mixed with a standard phosphate solution of which 5 c.c. contain 0-5 milligram of phosphorus. 

Barr et al. and Bravo et al. used a different technique for sample preparation and determination of alkyl phosphates in urine the urine was spiked with internal standard and then concentrated to dryness via azeotrope codistillation with acetonitrile. The residue was dissolved in acetonitrile, derivatized and then analyzed using GC-MS. Both studies reported satisfactory validation data with coefficients of variation of <20%. 

Kupfermann N, Schmoldt A, Steinhart H. Rapid and sensitive quantitative analysis of alkyl phosphates in urine after organophosphate poisoning. J Anal Toxicol 2004 28 242-8. 

Bradway DE, Shafik TM. Malathion exposure studies. Determination of mono- and dicarboxyhc acids and alkyl phosphates in urine. J Agric Food Chem 1977 25 1342-4. 

Lin WC, Kuei CH, Wu HC, Yang CC, Chang HY. Method for the determination of dialkyl phosphates in urine by strong anion exchange disk extraction and in-vial derivatization. J Anal Toxicol 2002 26 176-80. 

A modification of the GFAAS method for determining selenium levels in human urine was described by Saeed (1986). In this electrothermal atomic absorption spectrometry (EAAS) method, nitric acid, nickel, and platinum are added to the graphite cell. The addition of nickel helps to mask the spectral interference from phosphates in urine. EAAS has been used to determine selenium levels in human spermatozoa (Suistomaa et al. 1987). 

D.G. Themelis, A. Economou, A. Tsiomlektsis, P.D. Tzanavaras, Direct determination of phosphate in urine by sequential-injection analysis with single on-line dilution-calibration method and photometric detection, Anal. Biochem. 330 (2004) 193. 

ViiCHfiVafice determination of phosphates in urine.—A process for determining the quantity of phosphates in urine is based upon the formation of the insoluble uranium phosphate, and upon the production of a... 

USE Clinical reagent (phosphates in urine). Monophosphates give a yellow, dibasic a red, tribasic a violet color. Used in soln of 0.5 g in 100 ml 50% ale 2-3 drops for 100 ml liq. As sensitive indicator for acids, alkali hydroxides, NH2, but not for carbonates. Biological stain-... 

Kupfermann, N, Schinoldt, A., and Sieinhari, H. (2004). Rapid and sensitive quantitative analysis of alky phosphates in urine after organopho.sphate poisoning. J. Anal. Toxicol. 28, 42-48. 

It may seem disturbing that 1,25-(OH)2D3 can be considered a hormone with two signals (low calcium and low phosphoms) and two functions (calcium mobilization and phosphate mobilization). It would appear that a specific correction of the signal would not be possible. However, the calcium signal causes parathyroid secretion thus parathyroid hormone accompanies 1,25-(OH)2D3 in this circumstance, permitting mobilization of bone calcium and renal reabsorption of calcium. The effect of 1, 2S-(0H)2D3 on serum phosphate is negated by the parathyroid hormone induced loss of phosphate in urine. The composite effect of the low calcium signal is to elevate serum calcium but not phosphate ... 

Binding of Excreted Hydrogen ions on secondary Phosphate in urine... 

Bradway, D. E., and Shafik, T. M. Malathion Exposure Studies. Determination of Mono- and Dicarboxylic Acids and Alkyl Phosphates in Urine... 

Determination of Mono- and Di-carboxylic Acids and Alkyl Phosphates in Urine... 

Cadmium seems to be concentrated in the kidney and it disrupts the reabsorption in the tubules of cations such as calcium (II) and anions, particularly phosphate. The mechanism of disruption is not very well understood, but is considered to be an inhibition of some ion-transport pumping enzymes. One of the results is loss of calcium and phosphate in urine. They have to be supplied from bones in order to maintain their concentration in the blood. Hence, the bone is lost osteoporosis. 

In nitric acid medium, the precipitation of uranyl phosphate is incomplete. Uranyl monohydrogen phosphate is insoluble in water and in an acetic acid solution. It is soluble in mineral acid medium. These points explain the use of the acetic buffer to carry out the precipitation. One may also use uranyl acetate instead of nitrate, but the former is less stable than the latter. The titration is performed at about t = 80°C. The indicators are either cochineal tincture as internal indicator or potassium ferrocyanide as an external one. Cochineal tincture is an acid-base indicator. It is obtained by the extraction of cochineal by alcohol. The principal application of this precipitation reaction occurs in the field of analytical biochemistry. More precisely, it is the determination of phosphates in urine. Although this procedure is superseded by colorimetric methods, it remains an interesting replacement method. 

---