GRADIENT ION CHROMATOGRAPHY WAS USED FOR THE SEPARATION OF EIGHT SUGARS: arabitol, cellobiose, fructose, fucose, lactulose, melibiose, N-acetyl-D-glucosamine, and raffinose. The separation method was optimized using a combination of simplex or genetic algorithm with the isocratic-to-gradient retention modeling. Both the simplex and genetic algorithms provided well separated chromatograms in a s...

We have developed a high performance liquid chromatography (HPLC) method to separate lecithin from other phospholipid classes and to obtain lecithin from biologic materials. The separation was performed on a preparative 10-micron Spherisorb column with an optimized solvent system consisting of the following components: acetonitrile, isopropanol, methanol, water, and trifluoroacetic acid. The ad...

The separation of myo-inositol phosphates by ion pair, reverse-phase high performance liquid chromatography has been investigated. The retention of the inositol phosphates is dependent on both the polarity of the hetaeron utilized and on the pH of the solvent. A method is presented which permits the isocratic separation of multiple forms of inositol phosphates including isomers of myo-inositol ...

an ion chromatography (ic) method for simultaneous determination of benzoic, salicylic and sorbic acids was developed. in this method the samples were purified by solid-phase extraction. the analytes were then eluted with methanol from c18 cartridge. the separation was performed on ion-exclusion column by an isocratic elution with 0.25 mmol /l sulfuric acid solution containing 20% (v/v) acetone...

the present study was designed to develop a simple, validated liquid chromatographic method for the analysis of azithromycin in bulk and pharmaceutical dosage forms using ultraviolet detector. the best stationary phase was determined as c18 column, 5 µm, 250 mm × 4.6 mm. mobile phase was optimized to obtain a fast and selective separation of the drug. flow rate was 1.5 ml/min, wavelength was se...

The present study reveals a simple isocratic RP-HPLC method for the simultaneous determination of dextromethorphan hydrobromide and levocetirizine dihydrochloride in a cough syrup. The separation of these compounds was achieved within 10 min on a Phenomenex (USA) C(18) analytical column, 250×4.0 mm i.d., using an isocratic mobile phase consisting of potassium dihydrogen phosphate buffer (pH 2.5...

A simple, precise, and accurate isocratic RP-UFLC stability-indicating assay method has been developed to determine trospium chloride in tablet dosage form. Isocratic separation was achieved on an Enable-C18G (250 mm × 4.6 mm i.d., particle size 5 μm) column at room temperature, the mobile phase consisted of acetonitrile:0.01M TBAHS (50:50, v/v) at a flow rate of 1.0 ml/min, the injection volum...

The present study was designed to develop a simple, validated liquid chromatographic method for the analysis of azithromycin in bulk and pharmaceutical dosage forms using ultraviolet detector. The best stationary phase was determined as C18 column, 5 µm, 250 mm × 4.6 mm. Mobile phase was optimized to obtain a fast and selective separation of the drug. Flow rate was 1.5 mL/min, Wavelength was se...

The present study was designed to develop a simple, validated liquid chromatographic method for the analysis of azithromycin in bulk and pharmaceutical dosage forms using ultraviolet detector. The best stationary phase was determined as C18 column, 5 µm, 250 mm × 4.6 mm. Mobile phase was optimized to obtain a fast and selective separation of the drug. Flow rate was 1.5 mL/min, Wavelength was se...

With so many options for method parameters to adjust during development, identifying a starting point can be intimidating. Starting with scouting gradients simplify the process, and yield rich results that inform subsequent development steps. In this installment, we discuss how design gradients, use resulting data make decisions about next steps (including whether isocratic or gradient elution)...