Cancer Prodrug Analyzed with HPLC – AppNote

Separation Achieved with Shape Selectivity and Hydrophobic Interaction This Method provides an example of Reversed Phase Separation containing a number of related compounds. The properties of the solutes are listed in the Table below. When comparing the properties of Compounds 2 and 3, it is interesting to note that 2 is more hydrophobic than 3 […]

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Corticosterones Analyzed with LCMS – AppNote

Serum Corticosterones Concentration Determinations Serum Corticosterone Concentrations are of clinical significance in Adrenal dysfunction. Its measurement is sometimes used to diagnose apparent mineral Corticoid Excess Syndrome. It can also be used as a bio marker of malignancy in Adrenal Tumors. Using this Method allows the simultaneous measurement of the two main Estrogen fractions, Estrone and Estradiol […]

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Determination of Atropine with HPLC – AppNote

Rugged & Fast Without Paired Ion Reagents Ion-pair Chromatography (IPC) is commonly used in order to retain Atropine on ordinary Reversed Phase HPLC Columns. Beside long equilibration times with these columns, IPC often suffers from poor robustness. Using an isocratic elution with flow rate 1mL / minutes gave symmetrical peak for this Tropane Alkaloid. The […]

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Doxycycline Analyzed with HPLC – AppNote

Forced Degradation Method Using Shape Selectivity Doxycycline is known to epimerize at the C4 and C6 positions in acid conditions. Epimers can be difficult to separate in Reversed Phase due to subtle differences in hydrophobicity. However, this Method differentiates based on shape as well as hydrophobicity and is therefore well suited to this Isomer separation. […]

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Doxycycline and Methacycline Analyzed with HPLC – AppNote

Simple Isocratic Method for API and Main Impurity Formulations of Doxycycline may contain a Methacycline Impurity.  As such, it is crucial for analytical methods to be able to separate these two peaks. Using this simple isocratic Method, the baseline resolution is obtained for this pair. Peaks: 1. Methacycline 2. Doxycycline * Impurities in doxycycline standard […]

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Hormone Replacement Capsule Analysis with HPLC – AppNote

Separation of Estriol, Estradiol, & Progesterone This gradient method features a separation of the three components of a hormone replacement formulation. Figure A shows a five run overlay of the formulation extract injections. Figure B shows a zoomed-in view so that the Estriol and Estradiol Peaks, which are present in much lower concentration than Progesterone, can […]

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Human Plasma Extract Analyzed by LCMS – AppNote

 Urea, Lactodifucotetraose, Trimethylamine, L-carnitine & Choline Using this Method it is possible to analyze Compounds present in a Human Plasma Samples. The mechanism of retention of these polar compounds on the Column used is unknown at this time. It is possible to Retain and Separate steroids and other Compounds based on the Shape of the […]

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Limonin in Orange Juice Analyzed with HPLC – AppNote

Reproducible Separation from Sample Matrix Peaks An Orange Juice Sample was spiked at the level of 250 ppm of Limonin and filtered (MicroSolv Tech Corp. 0.45μm Nylon Syringe Filter)  before injection. Several Peaks from to the Juice Sample Matrix were separated (peaks1–5), the Limonin peak was well separated from the other Peaks and was easy […]

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Meloxicam Tablet Analyzed with HPLC – AppNote

Rapid, Reliable Isocratic Method for this API The USP Assay Monograph Method for Meloxicam uses a phosphate based Mobile Phase. In this application note, a 0.1% Formic Acid additive is chosen in lieu of phosphates in order to be LCMS compatible. The System Suitability requirement is not more than 2.0 for Tailing factor. Highly Symmetrical […]

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Morphine Sulfate Tablet HPLC Method Transferred to Near UHPLC – AppNote

Standard 4um Particle Size Transferred to 2.o™ This application illustrates how methods developed using the 4µm Cogent Diamond Hydride Columns may be adapted for Cogent Diamond Hydride 2.o™ phases. Morphine shows slightly higher retention on the 2.o™ Column (average 7.311 min vs. 5.588 min). The efficiency is almost twice as high when using the smaller […]

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Nucleoside Analogs Analyzed with HPLC – AppNote

Polar and Non-Polar Anticancer Prodrugs Analyzed in the Same Run In this Method, we display Retention of both polar and nonpolar compounds in a simple Isocratic run. Adjustment of the aqueous to organic ratio can be used to make either the polar or more hydrophobic compounds elute first. In the example presented, the more hydrophobic […]

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Oleic Acid & Elaidic Acid – AppNote

Advantages of shape selectivity in cis/trans separations The separation of cis and trans isomers by Reversed Phase can be challenging, as the two compounds often have little difference in hydrophobicity. In cases such as these, additional selectivity mechanisms may be necessary to obtain resolution. Furthermore, they cannot be resolved by MS because they have the […]

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Shape and Size Selectivity of HPLC Columns – AppNote

Separation of Planar Molecules in HPLC using the Cogent UDC-Cholesterol Column When comparing Cogent UDC-Cholesterol™ and Cogent Bidentate C18™ Columns, the Cholesterol phase is generally less hydrophobic under the conditions in this Application Note. However from the two Chromatograms shown, a very interesting property of the Cholesterol Phase can be observed; the Cholesterol Column exhibits […]

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Vitamin K Isomers Analyzed with HPLC – AppNote

Phytonadione Separation by Shape Selectivity In this Method, we separate the two E and Z isomers of Phytonadione on the basis of shape selectivity. The below chromatogram is a five injection overlay with a resolution value of 1.5.  Peaks: 1. Impurity 2. Phytonadione (E isomer) 3. Phytonadione (Z isomer) Method Conditions Column: Cogent UDC-Cholesterol™, 4μm, […]

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