Analyses biologiques

Articles

Featured Application: 231 pain management and drugs of abuse compounds in under 10 minutes
by LC-MS/MS

As shown in this featured application, Restek's Raptor Biphenyl column is ideal for developing successful LC-MS/MS pain medication screening methodologies. With its exceptionally high retention and unique selectivity, 231 multiclass drug compounds and metabolites—including over 40 isobars—can be analyzed in just 10 minutes.

Featured Application: LC Analysis of Vitamin D Epimers on Raptor FluoroPhenyl Columns

Raptor FluoroPhenyl columns can provide greater selectivity and retention for analytes that are not easily separated using a C18 column. For example, the epimeric forms of vitamin D2 and D3 25-hydroxy metabolites are important diagnostic markers for vitamin D status, but these compounds cannot be distinguished on a C18 column. The new Raptor FluoroPhenyl column provides ample chromatographic resolution for these isobaric epimers, which possess unequal bioactivities, so accurate results are generated and thus the proper diagnosis can be made.

A Rapid and Sensitive LC-MS/MS Method for the Analysis of Three Forms of Thyroid Hormones Using Raptor™ Biphenyl LC Columns

The Raptor Biphenyl column is excellent for rapid and sensitive analysis of thyroid hormones. With the method described here, concentrations of thyroid hormones as low as 2 pg/mL (T3) or 5 pg/mL (T4 and rT3) can be determined with less than 3.5 minutes of total analysis time. The analytical method is thus applicable to the clinical analysis of free thyroid hormone at low pg/mL levels.
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An Evaluation of Biphenyl Chemistry to Aid in High-Throughput Bioanalytical LC-MS/MS Analyses

Fully porous UHPLC and superficially porous HPLC columns increase efficiency and peak capacity and decrease analysis times, but don't directly impact selectivity or retention. The Biphenyl phase utilizes aromatic selectivity and hydrophobic retention to give greater retention and selectivity, therefore offering advantages on throughput, data quality, sensitivity, and resolution in bioanalytical work. (PDF - 0kB)

Characterizing Cellular Fatty Acid Methyl Ester (FAME) Profiles to Identify Bacteria Using Gas Chromatography

Dr. Radomír Čabala, Head of the Toxicology Department at the General University Hospital in Prague, presents work on the potential utility of GC-TOFMS analysis of cellular fatty acid methyl esters (FAMEs) in identifying clinically relevant bacteria.

Easily Resolve Oxytocin PEGylation Reaction Products

Viva Wide Pore HPLC columns are ideal for the separation of large molecules, as target analytes can enter the larger pores and access more of the surface area. Here we demonstrate the added retentive power of these columns, using the PEGylation of oxytocin as an example. Separation of these large, closely related compounds demonstrates the suitability of Viva Wide Pore columns for monitoring PEGylation reactions, and other large molecule applications.

Improve Characterization of Complex Protein Digests

A Viva C18 wide pore HPLC column resolves a tryptic digest of bovine serum albumin primarily into 1-2 peptide peaks, versus peaks of 3 or more peptides typically provided by conventional C18 columns. This superior resolution helps ensure more reliable identification of peptides in complex mixtures.
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Colonnes “core-shell” Raptor™ Biphenyl

Les colonnes Raptor™ Restek associent la rapidité des analyses avec le pouvoir de résolution liée à la grande sélectivité des colonnes USLC. La phase Biphenyl est particulièrement appréciée pour son aptitude à séparer les composés pour lesquels les phases C18 ou de type phényl ne sont pas assez résolutives ou rétentives. Les colonnes Raptor™ s’avèrent extrêmement utiles pour obtenir des séparations rapides mettant en œuvre des analyses de substances médicamenteuses ou leurs métabolites. (PDF - 0kB)

Reduce Downtime with Robust Lipidomics Method

Labs can save days of downtime by using an Rxi®-5ms column in assays similar to this high-throughput test method for cholesterol and low-level sterol metabolites. Here, extremely reproducible results were obtained using an Rxi®-5ms column, which gave highly consistent separations — even after 10,000 injections. Consistent performance and long column lifetimes increase productivity by reducing downtime associated with column changes and revalidation.
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Resprep PPT 96-Well Plates Sales Sheet

Protein and particulate removal that’s fast, painless, and effective. Restek’s line of Resprep sample preparation products has expanded to include new 96-well protein precipitation (PPT) plates. Prepare serum, plasma, and other biological samples using the name you trust for quality, cleanliness, and performance. (PDF - 0kB)
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The Analysis of Vitamin D Metabolites in Serum/Plasma by LC-MS/MS

Separating fat‐soluble vitamins and their metabolites by LC can be quite time consuming, taking up to 20 minutes or longer by some methods. However, the new Raptor ARC‐18 LC column can analyze these difficult compounds using reversed phase chromatography (RPC) in much less time, which helps increase sample throughput and overall lab productivity. This technical poster presents methodology that provides excellent quantitative results for metabolites 25‐hydroxyvitamin D2 and 25‐hydroxyvitamin D3 in analysis times of less than 2 minutes. Parent compounds vitamin D2 and vitamin D3 eluted in less than 4 minutes. (PDF - 0kB)
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Viva Wide Pore HPLC Columns Brochure

Viva wide pore HPLC columns offer the largest surface area available in 250-350 Å pores, giving maximum retention and resolution of proteins, peptides, and other large biomolecules. Includes product information and chromatography for the PEGylation of oxytocin. (PDF - 0kB)