Although analysis of VOCs by purge and trap is considered a mature technique, advances in methodology and refinement of instrumentation are still being developed. This application note presents suggested operating conditions for the 4760 purge and trap and the 4100 autosampler. Download PDF
USEPA Method 524.2 has been used by laboratories for many years for the analysis of volatile organic compounds in drinking water by purge and trap concentration with detection using Gas Chromatography/Mass Spectrometry (GC/MS). This method requires an 11 minute purge at 40 mL/minute and a 4 minute desorb. The 4 minute desorb transfers a significant…
The analysis of organic compounds in aqueous environmen tal, biomedical, food and fragrance matrices is normally performed after extraction and enrichment of the solutes from the matrix (drinking water, waste water, body fluids, beverages,…). Most used sample preparation methods are based on liquid-gas extraction or equilibrium (purge and trap, headspace), liquid-liquid extraction or solid phase…
2,4,6-Trichloroanisole (TCA) is well known as being the main cause for corkiness in wine. Its extremely low odor threshold usually mandidates enrichment and concentration steps before it is available for precise quantitation. This paper describes the applicability of a recently developed, novel and simple approach for sorptive extraction of organic compounds from aqueous samples for…
The analysis of flavor compounds in beverages such as coffee, tea, soft drinks and alcoholic beverages usually requires cumbersome sample preparation steps such as liquid/liquid extraction, solid phase extraction or distillation techniques, often with the drawback of organic solvent use. Headspace and purge & trap methods do not use organic solvents, but their analyte range…
The analysis of flavor compounds in dairy products such milk, cream, yoghurt and cheese as well as their blends with several ingredients usually requires cumbersome sample preparation steps such as liquid/liquid extraction, solid phase extraction or distillation techniques, often with the drawback of organic solvent use. Headspace and purge & trap methods do not use…
The analysis of volatiles in solids is a common analytical problem. Examples include volatile aroma compounds in foods and plant materials (coffee, tea, and herbs), residual fragrances from soaps and fabric softeners on textiles, and volatiles in polymer resins, films and plastic products. Several techniques are available that allow direct analysis of the volatiles in…
The analysis of volatiles in solids is a common analytical problem. Examples include volatile aroma compounds in foods (coffee, tea, herbs), residual fragrances from soaps and fabric softeners on textiles, and volatiles in polymer resins, films and plastic products. When high sensitivity analysisis needed, many of these sample types can be analyzed by direct thermal…
Flavor is an important quality criterion for virgin olive oils. The identification of the compounds causing the flavor or off-flavor therefore is the key for quality control. Their analysis in olive oils usually requires more or less cumbersome sample preparation like liquid/liquid extraction, solid phase extraction or distillation techniques, often with the drawback of organic…
Direct thermal extraction of solids has most commonly been used for qualitative identification of trace materials such as additives, impurities and residual monomer or solvents. The technique has many benefits including reduced matrix interference, eliminating solvent extractions, and significant improvements in detection limits relative to liquid extraction techniques. Many types of solid materials are amenable…
The analysis of volatile and semivolatile compounds in aqueous solutions using stir bar sorptive extraction (SBSE) as the extraction step is gaining acceptance in a wide variety of application areas including water, beverages and other consumer products. It has been shown to be simple, sensitive and often can eliminate cumbersome solvent extraction or other sample…
Analysis of samples containing polar matrix components such as water, glycols, sugars or surfactants by gas chromatography has usually required extensive cleanup such as liquid/liquid extraction, solid phase extraction or distillation. Some polar matrix components like acetic acid or ethanol are highly volatile and difficult to eliminate using traditional sample preparation techniques. Poor analyte peak…
The elucidation of the “hoppy aroma note” in beer has always been a challenging task. The main reason without any doubt is the lack of sensitive and selective analytical methods. In the brewery industry, organoleptic panels very often identify a hoppy note in beers, but analytical evidence cannot support their observations. Two new sampling techniques,…
Generally the analysis of the bitter principles in beer and wort is done by liquid/liquid extraction [1] or C8 SPE extraction followed by HPLC analysis [2]. Unfortunately, there is a lack of reproducibility, a high consumption of organic solvents and only the main compounds i.e. the humulones and iso-humulones, can be monitored by this methodology.…
The benefits of using a Programmed Temperature Vaporizer (PTV) type inlets instead of hot split/splitless (S/SL) inlets for the liquid and headspace (HS) measurements of volatile compounds are shown. We used benzaldehyde as a model compound to show the possibility of oxidation or thermal decomposition of sample compounds in a hot S/SL inlet. Liquid and…
A new technique that uses a chemical sensor coupled with multivariate analysis is evaluated and applied to discriminate soft drinks from different vendors. The headspace volatiles of different cola samples were analyzed using a chemical sensor that uses quadrupole mass-spectrometer technology. Analysis times per sample averaged between 3 to 4 minutes. Soft drink samples were…
The FDA requires that any food-contact materials that may reasonably be expected to migrate into food must conform to existing regulations or be included in a petition proposing a new regulation. Alternatively, a no-migration status can be established by showing the packaging component is not detectable in food with a method with a LOD typically…
The use of stir bar sorptive extraction (SBSE) as a technique to extract volatiles and semivolatiles from polar, especially aqueous matrices, has gained more and more acceptance in several application areas. Thermal desorption, analogous to SPME, has been found to be the most suitable technique to transfer the extracted analytes into an analytical system and…