The Application Notebook-06-01-2012

Concurrent solvent recondensation–large volume splitless injection (CSR-LVSI), an alternative to programmed temperature vaporization (PTV), typically requires a special GC inlet. The technique described here uses an unmodified split/splitless inlet with CSR-LVSI to lower detection limits for the analysis of 1,4-dioxane in drinking water.

Diesel range organic (DRO) compounds have boiling points similar to diesel fuel (C10–C28), ranging from 170–430 ?C. These heavy compounds are amenable to GC-FID analysis; however, important considerations should be taken to ensure reproducible results over repeated injections.

The Application Notebook

This application note will demonstrate the extraction of 1,4-dioxane from an aqueous matrix using option 1 of EPA Method 522 for 500 mL initial volume sample. It will make use of the SmartPrep Cartridge Extraction system to produce a valid initial demonstration of precision (IDP) and initial demonstration of accuracy (IDA).

The Application Notebook
Pharmaceutical/Drug Discovery

June 01, 2012

Excipients are pharmacologically inactive substances used as carrier and release controllers for active drug ingredients. A significant amount (30–80% solid) of polymeric excipients such as hydroxyl propyl cellulose (HPC), hydroxypropyl methyl cellulose (HPMC), hydroxypropyl methyl cellulose acetate succinate (HPMCAS), and povidone are used.

This application demonstrates that stringent sensitivity requirements for the detection of potentially harmful primary aromatic amines can be fulfilled when using an Agilent 1290 Infinity LC system equipped with the 1290 large volume injection kit.

The Application Notebook

Polyimide coated fused silica capillary tubing is widely used in the separation sciences. In some instances a condition called brittleback can appear in the tubing. Its causes and remedies are discussed.

The Application Notebook

Heterocyclic amines (HCAs) are a class of compounds that are formed when amino acids from meat proteins react with glucose and creatine under high-temperatures, as is associated with frying or grilling over an open flame (1–3). Studies have correlated the consumption of high levels of HCAs with an increased risk of some forms of cancer.

The Application Notebook
Pharmaceutical/Drug Discovery

June 01, 2012

Protein heterogeneity is generated by post-translational modification, decomposition, and a variety of other processes, including chemical modification, denaturation, and aggregation. Since antibodies and recombinant proteins are now widely used for therapeutic treatment, it is essential to evaluate their heterogeneity during development, stability testing, and in the quality control of the final product.

The FDA has made changes to how products containing sunscreen are labeled in the U.S. to ensure they meet the new regulations set forth for safety and effectiveness. The new regulations will require companies that want to use the "broad spectrum" label to test for both UVA and UVB protection.

The United States Environmental Protection Agency (US EPA) has established the Unregulated Contaminant Monitoring Program to collect data for contaminants suspected to be present in drinking water (1). The US EPA is currently proposing Unregulated Contaminant Monitoring Rule 3 (UCMR 3) which will collect data from January 2013 through December 2015. Because of the impact on public health and safety, it is vital to have a system that can detect and analyze for these compounds at low levels.

The need to increase the use of low valued co-products derived from the processing of sugar beets has prompted the investigation of the structure of the pectin extracted from sugar beet pulp. The characterization of sugar beet pectin is essential as it has the potential to be used in the production of industrial products, e.g., as an emulsifying agent in food systems.

Ascentis Express 5 micron columns provide a new choice for improving the performance of traditional HPLC systems. Based on Fused-Core particle technology, Ascentis Express provides the benefits of high speed and high efficiencies without the concerns of smaller particle columns. Due to the high efficiencies at low backpressures, Ascentis Express 5 micron can benefit conventional HPLC users with no drawbacks.

The Application Notebook

The analysis of PAHs in less than 16 min using hydrogen as carrier gas and the PerkinElmer? Clarus? SQ 8 GC/MS operating in SIM mode is presented. Detection limits down to 0.5 pg on-column and a wide dynamic range are reported.

The Application Notebook

Biotherapeutic peptides and proteins are often PEGylated (covalently bonded to polyethylene glycol polymers) to improve bioavailability, reduce immunogenicity, and extend circulating half-life (1). Achieving the desired properties for each application depends on optimizing the number and site of polymers attached, chain length, and the degree of chain branching.

Antioxidants protect cells from the damaging effects of free radicals and offer numerous benefits for human health. Many phenolic compounds found in plants, as well as some vitamins, exhibit antioxidant activity. Several colorimetric assays exist to measure the total antioxidant capacity, typically expressed as Trolox or Gallic acid equivalents.

The efficiency of ion transfer between the quadrupole mass analyzers and the Q2 collision cell in a triple quadrupole mass spectrometry (MS) is critical for instrument robustness and sensitivity. Q2 is a radio frequency (RF) only non-mass filtering quadrupole containing only an inert collision gas such as Ar, He, or N2 to provide collision induced dissociation of the precursor ion selected in Q1.

The Application Notebook

Simple, rapid and accurate methods have been developed for the analysis of simple carbohydrates including mono- or disaccharides, or as fairly small glycans (6–11 residues) liberated from glycoproteins using charged aerosol detection combined with mass spectrometry techniques.

Low-molecular-weight heparins (LMWHs) are obtained by fractionation or depolymerization of natural heparins. They are defined as having a mass-average molecular weight of less than 8000 and for which at least 60% of the total weight has a molecular mass less than 8000.

Plastics and other polymers are used in a wide spectrum of applications from industrial usage to packaging, including the packaging of food and pharmaceutical products.

Typical chiral stationary phase (CSP) screening paradigms utilize a single alcohol component as co-solvent in its mobile phase. Recent unexpected observations have demonstrated that mixed-alcohol mobile phases can enhance or even introduce peak resolution when none existed in a mono-alcohol system.

The Application Notebook

Insulin was the first recombinant pharmaceutical produced. Currently, one of the critical quality control attributes of therapeutic insulin in the US and European Pharmacopoeia (USP and EP) monograph is the level of covalent high molecular weight (HMW) insulin as determined by HPLC size-exclusion chromatography.

The Application Notebook
Pharmaceutical/Drug Discovery

June 01, 2012

Malaria remains one of the world's most deadly diseases, killing a child under five years of age every 30 s. Our branch aims to produce and characterize recombinant protein vaccines for Phase I and II human trials.

Ion exchange is a perfect technique for analyzing large biomolecules such as proteins, peptides and oligonucleotides. These complex compounds contain numerous components (amino acids, nucleotides, glycans etc.) many of which possess a charged side chain or backbone.

The Application Notebook

Selective cleavage of proteins by the enzyme trypsin helps characterize larger proteins. While MS provides structural information, quantitative analysis is often based on detection by UV at 214 nm.

When working with complex matrices such as personal care products, sample preparation is perhaps the most difficult step of the analysis process. By utilizing a targeted sample preparation technique, such as ion-exchange SPE, analysis can be significantly improved as compared to less targeted techniques such as liquid-liquid extraction.

Compounds such as ibuprofen, chlorpheniramine, and allantoin are important in the field of pharmaceuticals and cosmetics. The analysis of acidic and basic compounds is particularly important but it is sometimes difficult to analyze both acidic and basic compounds on a single standard C18 column. Imtakt's Scherzo SM-C18 and Scherzo SW-C18 HPLC columns can separate acidic ibuprofen and basic chlorpheniramine simultaneously.

The Application Notebook

Resistive glass tubes and plates are designed to guide ions by generating a uniform electric field. Photonis resistive glass products are composed of a proprietary lead silicate glass that has been specially processed to create a resistive layer at the surface. The resistivity can be varied over several orders of magnitude to suit the specific application.

The Application Notebook

This application note demonstrates the use of the Thermo Scientific Syncronis C18 1.7 ?m column for the determination of esomeprazole by UHPLC-UV.

Plant materials contain a wealth of information on plant viability and health. The analysis of the metabolite contents of the leaves of various plants has been informative in the comparison of organisms.

The Application Notebook

This application note demonstrates the use of the Thermo Scientific Accucore RP-MS column for the determination of telmisartan by HPLC-UV.