Buffers disodium hydrogen phosphate

Zarghi et al. [76] developed an HPLC method, using a monolithic column, for quantification of omeprazole in plasma. The method is specific and sensitive with a quantification limit of 10 ng/ml. Sample preparation involves simple, one-step extraction procedure, and analytical recovery was complete. The separation was carried out in reversed-phase conditions using a Chromolith Performance (RP-18e, 100 x 4.6 mm) column with an isocratic mobile phase consisting of 0.01 mol/1 disodium hydrogen phosphate buffer-acetonitrile (73 27) adjusted to pH 7.1. The wavelength was set at 302 nm. The calibration curve was linear over the concentration range 20-1500 ng/ml. The coefficients of variation for intra- and interday assay were found to be less than 7%. 

Anhydrous disodium hydrogen phosphate Buffering agent, pH adjustment, solubilizer, stabilizer, suspending agent iv, im, sc, other inj. 

The epoxides (81) themselves have been synthesized by treatment of 4,7-dihydro-1,3-dioxepins (77) withp-nitro- <75BSF1763> or w-chloroperbenzoic acid <75TL2643> or HOCI/H2O2 <8IEUP33426). Alternatively, hexafluoroacetone/hydrogen peroxide in disodium hydrogen phosphate buffered... 

Sample preparation Condition a Bond Elut SCX strong cation exchange SPE cartridge with 1 mL MeOH, 1 mL water, and 1 mL 1 mM pH 7.0 disodium hydrogen phosphate buffer. Mix 500 tiL plasma or 100 tiL urine with 100 tiL 20-50 xg/mL IS in water and 100-500 16% trichloroacetic acid, add the supernatant to the SPE cartridge, wash... 

In addition, buffer salts such as disodium hydrogen phosphate may be used to prevent the pH of the aqueous phase falling during polymerisation. Small amounts of an anti-foam agent may be employed to reduce frothing when discharging from the vessel at the end of the polymerisation process. 

Three gradients of 0.0-0.5 M sodium chloride were run consecutively at 4°C in 0.05 M sodium acetate-acetic acid, 1 mM sodium azide, pH 5.25, followed by 0.05 M sodium acetate-acetic acid, 1 mM sodium azide, pH 3.5, and finally by 0.05 M sodium dihydrogen phosphate-disodium hydrogen phosphate (approx. 1 3), 1 mM sodium azide, pH 7.0. After sample application, the column was washed with the starting buffer to remove any non-bound compounds. Elution was continued with the high salt buffer. Fractions of 4 ml were collected and assayed for reactivity towards ninhydrin and for electric conductivity (salt concentration) after 75-fold dilution of a 100-pl aliquot. Ninhydrin-positive fractions were pooled for each peak, concentrated, and desalted by size exclusion chromatography (see above). 

The sodium acetate-acetic acid combination is one of the most widely used buffers, and is usually referred to simply as acetate buffer. Other buffer combinations commonly employed in chemistry and biochemistry include carbonate-bicarbonate (sodium carbonate-sodium hydrogen carbonate), citrate (citric acid-trisodium citrate), phosphate (sodium dihydrogen phosphate-disodium hydrogen phosphate), and tris [tris(hydroxymethyl)amino-methane-HCl]. 

X)8 695 m potassium dihydmgen phosphate. 0.030 43 m disodium hydrogen phosphate. Prepare like Buffer 5 dissolve 1.179 g KH2PO4 and 4.30 g Na2HPOA in water to give 1L erf solution at 25°C. 

M Sodium phosphate-buffer, pH 6.0- mix 12 mL of 1M disodium hydrogen phosphate with 88 mL of IMsodium dihydrogen phosphate, and make up to 1 L with water... 

Fig. 4 EUROMET comparison 370 [18]. Buffer disodium hydrogen phosphate, 0.03043 mol kg-1 + potassium dihydrogen phosphate, 0.008695 mol kg1 (7=37°C)...

Solutions Hepes buffer. Hepes (20 mM), sodium chloride (135 mM), potassium chloride (5 mM), magnesium chloride (1 mM), disodium hydrogen phosphate (1 mM), glucose (5 mM), pH 7.40, osmolarity 300 mOsm/kg H20. 

Commercially available 85% MCPBA is generally employed in chlorinated hydrocarbon solvents at room temperature. Reaction times are typically a few hours to several days. Buffers utilized include disodium hydrogen phosphate, sodium acetate and sodium bicarbonate, the catalytic effect of which has been occasionally noted. Acid catalysis with sulfuric acid or Nafion-H are alternatives. Oxidations have been performed at elevated temperature with the aid of radical scavengers. "... 

Eluent. Methanol water phosphate buffer (55 25 20). To prepare the phosphate buffer dissolve 11.038g (0.092M) of sodium dihydrogen phosphate and 1.136 g (0.008M) of disodium hydrogen phosphate in sufficient water to produce 1000ml. 

Table 7.4 Preparation of sodium phosphate buffer solutions for use at 25 °C. Prepare separate stock solutions of (a) disodium hydrogen phosphate and (b) sodium dihydrogen phosphate, both at 0.2 mol L . Buffer solutions (at 0.1 mol L"b are then prepared at the required pH by mixing together the volume of each stock solution shown in the table, and then diluting to a final volume of 100 mL using distilled or deionized water...

When sodium nafcillin solutions were frozen, the solute did not crystallize. However, annealing caused solute crystallization. It was also possible to monitor the amormt of sodium nafcillin crystallizing as a function of annealing time. XRD was also useful to characterize the behavior of buffer solutions. While disodium hydrogen phosphate crystallized when an aqueous solution was frozen, the presence of monosodium hydrogen phosphate inhibited the crystallization of the former. 

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