Agilent Manuals

This application note describes a fast and sensitive method for the determination of bisphenol-A in epoxy resins using GPC with an evaporative light scattering detector (ELSD). The method uses a narrow bore column and high flow rate for rapid separation, and Agilent ELSD provides excellent sensitivity and signal-to-noise ratio.

This document discusses methods for improving the extraction and purification of pharmaceutical compounds, as well as the use of FlowTrap columns to address issues caused by TFA acid.

This document introduces the quantitative GPC analysis application of poly(vinyl chloride) (PVC) and plasticizers. PVC is a thermoplastic widely encountered in everyday life. It is light, non-flammable, robust and durable. PVC is permeable, does not deteriorate, is easy to maintain and its physical and mechanical characteristics make it ideal for many different uses. Unplasticized PVC has a high melt viscosity leading to some difficulties in processing. The finished product is also too brittle for many applications. In order to overcome these problems, it is routine to incorporate additives to the PVC. In addition to acting as impact modifiers, a number of polymeric additives may be considered as processing aids. Such materials are primarily included to ensure more uniform flow and hence improve surface finish. The properties of the final material are dependent on the molecular weight distribution of the PVC and the type and level of the added plasticizers. The analysis of the compounded material is, therefore, of primary importance, and GPC is the ideal analytical tool for its characterization. With their linear resolving capability over a wide molecular weight range, PLgel MIXED columns provide resolution of both polymer and additives, particularly with the high efficiency 5 µm particle size columns.

This document introduces the method of using Agilent PLgel columns for GPC to analyze mono-, di-, and tristearoylglycerol.

This application note introduces the analysis of polysiloxane using GPC/SEC with RI and ELS detection on Agilent PLgel 5 µm MIXED-E column. Polysiloxanes are important commercial polymers used in applications such as lubricating oils, defoaming agents, and sealants. Analyzing these materials by gel permeation chromatography (GPC) is an important part of process and quality control procedures. Although polysiloxane is soluble in tetrahydrofuran (THF), it has the same refractive index as this solvent. Therefore, refractive index (RI) detection cannot be used with THF.

This application note describes a trial of the purity and stability of stored L-ascorbic acid powder samples from four different manufacturers, and assesses degradation compounds and/or precursors from the production process.

This document describes the use of tetracyclines and the USP method1 for the analysis of the compound

Effect of pH on Protein Size Exclusion Chromatography Application Note Introduction Determination of protein structure is key to understanding the function of many proteins. Molecule size is an indicator of structure and provides information on the quaternary structure of the protein. Many proteins undergo profound conformational changes in different solution conditions, with the most extreme being denaturation. Similar structural modifications may occur as a function of ionic strength, pH, temperature and changes in various other solution conditions. Proteins comprise amino acids, some of which have polar side chains or contain acidic or basic groups. At the isoelectric point, the protein is uncharged and charge repulsions of similar functional groups will be at a minimum, allowing aggregation to take place. Many proteins precipitate under these conditions, and even for proteins that remain in solution at their isoelectric point this is the pH of minimum solubility. At physiological pH most proteins are above their isoelectric point and have a net negative charge. A pH lower than the isoelectric point causes protonation of acidic groups and a net positive charge on the protein. In each case, the like- charges formed repel each other, reducing the likelihood of protein aggregation. However, in areas of larger charge density the intramolecular repulsion can lead to destabilization of the protein tertiary structure and subsequent unfolding. In some cases, this unfolding may lea...

This document introduces the application of Agilent PLgel column and GPC/SEC technology in oligomer separation, as well as the effect of particle size on separation effect

This application note describes a method for the analysis of dialkyl phthalates using an Agilent PLgel 5 µm 50Å column using gel permeation chromatography.

This application note demonstrates the analysis of tertiary-butyl mercaptan (TBM) in a natural gas matrix using the Agilent 490 Micro GC. The dimensions and instrument conditions for the column channel used in this application note, a CP-Sil 13 CB, clearly shows the separation of TBM from the other compounds in the natural gas sample. The advantage of the Agilent 490 Micro GC, in combination with the CP-Sil 13 CB column channel, is the ease of use and the speed of analysis. Tertiary-butyl mercaptan elutes just before 60 seconds and the total analysis time is only 100 seconds. The Agilent 490 Micro GC is a rugged, compact and portable lab-quality gas analysis platform. When the composition of gas mixtures is critical, count on this fifth generation micro gas chromatography.

This application note describes a method for characterizing xylooligosaccharides derived from xylan using aqueous SEC with HPLC. The method provides accurate separation and characterization of oligomers with similar molecular weights, with excellent sensitivity and stability.

This article introduces the use of PL-SAX strong anion-exchange HPLC columns for high-resolution separations of oligonucleotides. After deprotection of the oligonucleotide product, hydrophobicity-based separation can be performed, followed by anion-exchange HPLC for further resolution. The experimental results show that the PL-SAX column can achieve separation of n-1 from n.

This application note describes a fast reversed-phase HPLC method for the determination of aspirin, salicylic acid and phenacetin. The method uses a highly retentive polymeric reversed-phase column (PLRP-S 100Å) and gradient elution. The method provides excellent separation of the analytes, and can be completed in less than 10 minutes. The method is also highly reproducible and stable.

This report discusses the findings of an investigation into alternative solvents for the analysis of peptides on a SepTech ST150 10-C18