Additives tris phosphate

Tricresyl phosphate (a complex mixture containing tri-o, Xn-m-, and tri-para-cresyl phosphate that is used in certain hydraulic fluids) and TOCP are demonstrated testicular toxicants in rodents (Carlton et al. 1987 Somkuti et al. 1987a, 1987b). Tricresyl phosphate also has been shown to impair in vivo fertility in rats and mice (Carlton et al. 1987 Chapin et al. 1988a). In addition, tricresyl phosphate-treated female rats displayed vacuolar cytoplasmic alteration of ovarian interstitial cells (Carlton et al. 1987 NTP 1994). Reproductive effects have also been seen after oral exposure to butylated triphenyl phosphate (Latendresse et al. 1994b). 

Figure 3. Biosynthetic pathways from wyo-inositol (Ins) tetrad/,vphosphates to Ins(l,2,3,4,5,6)P6 (InsP6 or phytic acid ) and the pyrophosphate-containing Ins phosphates. The six carbons of the Ins ring are numbered according to the D-numbering convention. Questionmarks indicate synthetic steps that have not been confirmed in chemical, molecular or genetic analyzes. In addition, the tri-phosphate-containing 5-PPP-Ins(l,2,3,4,6)P5 is purely speculative. P = PH204.

Tris buffers Tris is also a much used buffer. However, it has one great disadvantage its pH is highly dependent on temperature and concentration. The pH of a Tris buffer will increase from 8.0 at 25 °C to 8.6 on cooling to 5 °C and on dilution of a 0.1 M solution at pH 8.0 to 0.01 M, the pH will fall to 7.9. This problem can only really be avoided by adjusting the pH of the buffer under the conditions of temperature and concentration where it is to be used. In addition, Tris has been shown, like phosphate discussed above, to interfere with many enzymic reactions, particularly those which have aldehyde intermediates. It also interferes with many chemical reactions, like the coupling of proteins to activated surfaces, and the Bradford assay for spectrophotometric determination of proteins. 

The purine ring system is undoubtedly among the most ubiquitous of all the heterocyclic compounds. This arises not only from the universal occurrence of adenine and guanine in DNA and RNA and of additional modified derivatives in the various tRNAs but also from the subsidiary uses of the ring system in very many biochemical systems Indeed across the whole spectrum of biochemical reactions in living systems there is hardly a reaction sequence which does not involve in some way a purine derivative such as the adenosine or guanosine mono-, di- and tri-phosphates, associated cyclic phosphates and nucleotide coenzymes. 

In addition to a role in the structure of membranes, phosphatidyl inositol serves as a precursor to inositol tris-phosphate, an important second messenger (Chapter 11.5). Phosphatidyl inositol is believed in some cases to serve to link proteins to phospholipid membranes (Section 11.1). 

In addition to the sugar component, at the 5 position of the ribose, nucleotides contain a mono-, di-, or tri-phosphate group. 

This uncertainty was resolved in a later report of a vanadyl—phosphate model system to investigate die eoordination structure of VO(ema)2 in bone mineral [96], Two, three, and ID 4-pulse, along wifli 2D HYSCORE spectroseopies were used to study the eoordination strueture of the vanadyl-triphosphate system. HYSCORE speetroseopy partnered with eontour Uneshape analysis determined three P hyper-fine eoupling eonstants of 15, 9, and 1 MHz, in exeellent agreement with the in-vivo results. In addition, detailed analysis of the proton matrix peak by ID 4-pulse ESEEM led to assignment of at least one, and probably two, water molecules in the equatorial plane. Thus, the VO-triphosphate model system demonstrated that the vanadyl ions in VO(ema)2-treated rat bone samples were most likely in a facial tris(phosphate) coordination with water moleeules oeeupying the vacant positions in the equatorial plane, as shown in Seheme 3. 

Nonreactive additive flame retardants dominate the flexible urethane foam field. However, auto seating appHcations exist, particularly in Europe, for a reactive polyol for flexible foams, Hoechst-Celanese ExoHt 413, a polyol mixture containing 13% P and 19.5% Cl. The patent beHeved to describe it (114) shows a reaction of ethylene oxide and a prereacted product of tris(2-chloroethyl) phosphate and polyphosphoric acid. An advantage of the reactive flame retardant is avoidance of windshield fogging, which can be caused by vapors from the more volatile additive flame retardants. 

Nickel Phosphate. Tri nickel orthophosphate [14396-43-17, Ni2(P0 2 7H20, exists as apple-green plates which decompose upon heating. It is prepared by the reaction of nickel carbonate and hot dilute phosphoric acid. Nickel phosphate is an additive to control the crystal size of ziac phosphate ia coaversioa coatiags which are appHed to steel prior to its being paiated (see Metal surface treatments). 

Tris(2-ethylhexyl) phosphate shows good compatibiUty with PVC and also imparts good low temperature performance in addition to good fire retardancy. 2-Ethyhexyl diphenyl phosphate has widespread use in dexible PVC appHcations due to its combination of properties of plasticizing efficiency, low temperature performance, migration resistance, and fire retardancy. 

Cosolvents ana Surfactants Many nonvolatile polar substances cannot be dissolved at moderate temperatures in nonpolar fluids such as CO9. Cosolvents (also called entrainers, modifiers, moderators) such as alcohols and acetone have been added to fluids to raise the solvent strength. The addition of only 2 mol % of the complexing agent tri-/i-butyl phosphate (TBP) to CO9 increases the solubility ofnydro-quinone by a factor of 250 due to Lewis acid-base interactions. Veiy recently, surfac tants have been used to form reverse micelles, microemulsions, and polymeric latexes in SCFs including CO9. These organized molecular assemblies can dissolve hydrophilic solutes and ionic species such as amino acids and even proteins. Examples of surfactant tails which interact favorably with CO9 include fluoroethers, fluoroacrylates, fluoroalkanes, propylene oxides, and siloxanes. 

The ionic species of the mobile phase will also affect the separation. This is shown in Table 4.3 by the difference in resolution values for magnesium chloride buffer compared to sodium sulfate buffer. In addition, calibration curves for proteins in potassium phosphate buffers are shallower than those generated in sodium phosphate buffers. The slope of the curve in Sorenson buffer (containing both Na and ) is midway between the slopes generated with either cation alone (1). Table 4.4 illustrates the impact of different buffer conditions on mass recovery for six sample proteins. In this case, the mass recovery of proteins (1,4) is higher with sodium or potassium phosphate buffers (pH 6.9) than with Tris-HCl buffers (pH 7.8). 

Marine diesels Again a wide number of formulations are in use. The inhibitors commonly employed include nitrites, borates and phosphates. Typical formulations include a 1 1 nitrite borax mixture at 1250-2000 p.p.m. and pH 8-5-9-0 and 1250-2 000 p.p.m. of nitrite with addition of tri-sodium phosphate to give phenolphthalein alkalinity. 

Water samples showing contamination by phenols are best examined by extracting the phenol into an organic solvent tri-n-butyl phosphate is very suitable for this purpose. Photometric measurements can be carried out on the extract, and the requisite alkaline conditions are achieved by the addition of tetra-n-butylammonium hydroxide. 

Fig. 7.1.3 Influence of the buffer and the type of peroxide on the luminescence reaction of Chaetopterus photoprotein. The reaction was initiated at zero time by the addition of a peroxide (old dioxane or H2O2) and FeSC>4 in each case, with successive additions of FeSC>4 or H2O2 at the time indicated with an arrow. In the experiments of the two upper curves, 10 pi of old dioxane and 1 pi of lOmM FeSC>4 were added at zero time, followed by 1 pi of 10 mM FeSC>4 at each arrow. In the experiments of the two lower curves, 50 pi of 10 mM H2O2 and 20 pi of 10 mM FeSC>4 were added at zero time, followed by 50 pi of 10 mM H2O2 or 20 pi of 10 mM FeSC>4 at each arrow. All in 5 ml of 10 mM phosphate or Tris buffer, pH 7.2. From Shimomura and Johnson, 1966.

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