Application Notes: GC
Method 6040D, Odors in Drinking Water, Using SPME on the Supelco SLB-5ms Capillary Column
June 1st 2008A method for trace odor components, isopropyl-methoxypyrazine (IPMP), isobutyl-methoxypyrazine (IBMP), methylisoborneol (MIB), and geosmin in drinking water involving the use of solid phase microextraction (SPME) and the SLB-5ms capillary column using gas chromatography/mass spectrometry (GC–MS).
Automated Sample Cleanup of Olive Oil
June 1st 2008Gel permeation chromatography (GPC) has been used as an effective cleanup procedure for removing high molecular weight interfering molecules such as lipids, pigments, proteins, and polymers before GC or HPLC analysis. The GPC cleanup method has been extensively documented (1–3) and is also recommended in US EPA SW-846 Method 3640A. To demonstrate the efficacy of this method to extract polar and nonpolar substances by using the KNAUER Smartline GPC Cleanup Unit 6500, olive oil samples were investigated by spiking these with different types of organic pollutants, including PAHs, phthalates, phenols, and triazine.
A "Solid" Alternative for Analysing Oxygenated Hydrocarbons — Agilent's New Capillary GC PLOT Column
December 1st 2007PLOT columns are often used in GC analyses when it is necessary or desirable to retain one class of solutes in favour of other solutes that have little or limited interactions with the surface of the stationary phase. With a PLOT column, chromatographers can even cause lower boiling point compounds to elute well after higher boiling point compounds, thus providing better qualitative and quantitative separations for the solutes of interest.
A Novel Method for the High-Speed Determination of Fuel Diluents in Lubricating Oils
September 1st 2007The performance of lubricating oil is significantly degraded by the presence of fuel contaminants such as gasoline and diesel. Recycled oil is particularly susceptible to this form of contamination. Consequently, producers and distributors of lubricating oil must go to great lengths to ensure the levels of fuel contamination are kept to a safe limit (typically 4–5%) in these products.
Accelerated Buffer System for Amino Acid Analysis
March 2nd 2007The continual increase in sample numbers in busy labs means that it is often difficult for quality control or contract analysis labs to maintain short turnaround times, particularly when instruments are already running at full capacity. To address the need for faster analysis while retaining the quality of separation offered by dedicated amino acid analysers, an improved formulation of sodium citrate based buffers has been developed by Biochrom.
Gas Chromatography–Time-of-Flight Mass Spectrometry in Food Analysis
January 1st 2007Gas chromatography (GC) coupled to time-of-flight mass spectrometry (TOF-MS) offers unique solutions for various analytical applications including the analysis of food quality, authenticity and safety markers. This article provides a general overview of TOF-MS basic features, highlighting its advantages and limitations compared with GC using conventional mass analysers. Examples of recent results obtained for selected food contaminants and flavour components are described to illustrate the potential of this recently introduced technique.
Innovations in Food Analysis — Analysis of Peptides, Additives and Flavours
December 2nd 2006The analysis of peptides and additives using a new HPLC innovative column technology, Pathfinder, was shown. For the analysis of flavours in lemon juice GC–MS with a new MS library, FFNSC, with linear retention indices was used.
Determination of Soft Drink Ingredients
December 2nd 2006Soft drink formulas often include preservatives, artificial sweeteners, flavours or caffeine in their list of ingredients. Using the Acclaim OA column, as many as eight common additives may be determined in a single run. Many of these additives are hydrophilic organic acids for which this column was designed. Notably, benzoate and sorbate, which do not resolve on C18 columns at low pH, are fully separated.
Optimizing Column Lifetime of TSK-GEL Size Exclusion Columns
December 2nd 2006Column lifetime is a more and more important issue when developing an analytical method for HPLC. Besides sample treatment, column cleaning and storage, operational parameters of the analytical method will have an influence on column lifetime. This question may not always be addressed early enough in the methods development process.
Determination of Protease Inhibitors Used in the Treatment of HIV
March 2nd 2005Protease inhibitors are a class of anti-HIV drugs used in combination therapy to block replication of the HIV virus in a person's blood. It is important to monitor the levels of these drugs in the patient since resistance can develop at low levels and at high levels the drug can exhibit toxic effects.