HPLC-grade phosphoric acid

Acetonitrile (ACN), tetrahydrofuran (THE), methylene chloride (DCM) and methanol (MeOH) were supplied by Labscan (Labscan Limited, Unit T26 Dublin, Ireland) and were of HPLC-grade. Chloroform ChromAR (Clf) was of analytical grade and supplied by Malinckrodt (Promochem GmbH, D-4230 Wesel, Germany). Methyl tert- butyl ether Uvasol (tBME), Acetic acid (100%) (HAc), triethylamine (TEA), phosphoric acid... 

The following solvents/reagents were used Concentrated formic acid and acetonitrile, both obtained from Promochem (Wesel, Germany) in HPLC grade quality. Isoproanol, ammonia (33%), methylene chloride and ortho-phosphoric acid (85 %) were supplied by Merck (Darmstadt, Germany) in analytical grade quality. 

Step 3. Now let us determine if ionizable components are present. For example, decrease the pH by adding 0.3 ml of phosphoric acid to 1 1 HPLC grade water, pH 4.0. Note, that you should actually measure the resulting pH even for preliminary experiments. Figure 5-9 illustrates the changes in the retention of a model mixture at pH 4.0. 

The solvents used were (a) HPLC grade methanol and acetonitrile (Fisher Scientific) (b) water, double-distilled and stored in glass. Inorganic salts and acid (ammonium sulfate, potassium phosphate monobasic, potassium phosphate dibasic and phosphoric acid, 85%) were analytical reagent grade (Malllnckrodt Chemical Works). 

Gradient reversed-phase HPLC methodology is used to quantify pergolide mesylate and its potential related substances (synthetic impurities and degradation products). A Supelco LC-18-DB column (25 cm x 4.6 mm 5 micron particle size) is used in conjunction with a flow rate of 1 mL/min. Detection is obtained with a U V detector set at 280 nm. The mobile phase components are a 0.5% morpholine buffer (v/v) in water (pH 7.0 with phosphoric acid) (A) and HPLC-grade methanol/acetonitrile/tetrahydrofuran (1 1 1) (B). A linear gradient is initiated at 30% (B) and increased 2%/minute for 35 minutes to a final concentration of 100% (B) then returned to 30% (B) and re-equilibrated for 20 minutes. The sample is analyzed at a concentration of approximately 3 mg/mL. 

Lanthanides in silicate rocks, commercial phosphoric acid, geological materials, refractory alloys, steel alloys, minerals, ores, monazite, and luminescent phosphors have been determined by HPLC. Determination of trace lanthanide impurities in nuclear grade uranium has been studied." An HPLC technique using the dynamic ion-exchange approach was also employed for the determination of Pm in urine. A typical application of lanthanide assay in nuclear industry is described next. 

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