Phosphoric acid buffer

Recently, a flow-injection method has been reported in which pKa values are measured by UV absorbance after injection into a flowing phosphoric acid buffer [40],... 

Capillary electrophoresis with diode array detection. Ultraviolet spectra (190-350 nm) were recorded after separation of fractions III, IV, and V-2 by capillary electrophoresis with diode array detection (CE-DAD) in 30 mM phosphoric acid buffer pH 2.3 and pH 7.2. Separations were carried out with a Hewlett-Packard 3D GE equipped with a diode array detector. Samples were introduced under pressure (30 mbar, 10 sec) into a fused silica capillary (effecfive lengfh 8 cm, total 64.5 cm, ID 50 pm, OD 375 pm) followed by separafion af 30 kV. 

Fig. 7. Measured and simulated absolute magnitude 2D-IR rephasing spectra of a 25mer a-helix with double isotope substitutions denoted as [ 3C= 60, l3C= 80]. (A) [12,13], (B) [11,13], Experimental condition D20-phosphoric acid buffer at 0° C. (C) and (D) are corresponding simulations.

To 2.0 ml of Amberlite XAD 7 was added 2.0 ml of a 0.05 M phosphoric acid buffer (pH 7.0) having dissolved therein 20 mg of lipoprotein lipase, and the system was allowed to stand at room temperature for 18 hours to thereby adsorb the enzyme onto the resin. The resin was filtered. A solution of 250 mg of 3,5-dinitrobenzoyl derivative of ()-3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine as a substrate in 25 ml of a mixed solvent of benzene and n-hexane (4 1 by volume) was added to the resin, followed by... 

Shao et al. recommended the use of a simultaneous fluorimetric method for the determination of the dissolution rate of dipyridamole and aspirin tablets [34]. The powdered tablets (equivalent to weight of one tablet) of dipyridamole and aspirin were dissolved in simulated digestive fluids at 37°C, cooled, and diluted to 1 L with simulated digestive juice. The solution was filtered, and a 1 mL portion of the filtrate was mixed with 0.1 M sodium hydroxide and then set aside at room temperature for 1 h. The solution was mixed with 8 mL of phosphoric acid buffer (pH 6.8) and fluorimetrically detected for dipyridamole at 493 nm (excitation at 418 nm). The coefficients of variation for within-day and within 5 days were 2% for both dipyridamole and aspirin. 

Phosphoric acid Buffer agent. Isotonicity, pH adjustment, solubilizing agent, stabilizer iv, im, sc... 

Two octadecyl columns were coupled in series and the alkaloids separated with a gradient of an increasing amount of acetonitrile in a triethylamine - phosphoric acid buffer (Fig.3.1). The influence of the pH on the separation of the alkaloids was studied optimum results were obtained at pH 7.56. The results were compared with a GLC and a spectrophotometric method. 

Analysis of the major tobacco alkaloids has been performed on an octadecyl column using a triethylamine - phosphoric acid buffer (pH 7.25) to which 40 methanol was added (Fig.3.2) (24). The method was compared with a GLC method. Several extraction solvents were compared as to their effectiveness. An 0.025 M phosphate buffer (pH 7.8) was found to be suitable. 

Mobile phase MeCN buffer 7 93 adjusted to pH 3.0 with 85% phosphoric acid (Buffer was 25 mM (NH4)H2P04 and 1 mM N,N-dimethyloctylamine.)... 

Mobile phase MeCN 0.025% phosphoric acid buffer 25 10 5 (A) or 60 25 15 (B) (Buffer was 9 mL concentrated phosphoric acid and 10 mL triethylamine in 900 mL water, adjust pH to 3.4 with dilute phosphoric acid, make up to 1 L.)... 

Mobile phase MeOH buffer 15 85, adjusted to pH 5.2 with phosphoric acid (Buffer was... 

Mobile phase MeCN bufiFer 36 64, pH ac usted to 3.7 with 10% phosphoric acid (Buffer was 7.8 g K2HPO4 in 500 mL water, adjust pH to 4.0 with phosphoric acid, make up to 1 L with water.)... 

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