Quantitative Headspace Measurement of Volatiles in Dairy Products using Vacuum Assisted Sorbent Extraction (VASE) and GCMS Analysis HS1003 (original) (raw)
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The odor of human milk induces search-like movements and oral activation in newborns, which increases their chances of taking advantage of milk intake and benefits. However, the underlying volatile fraction of human milk remains understudied. This study aimed to devise a simple method to extract a wide range of volatile compounds from small-volume human milk samples. Headspace solid phase micro-extraction (HS-SPME) with a Car/PDMS fiber and dynamic headspace extraction (D-HS) with a Tenax or a trilayer sorbent were tested because of their selective affinity for volatiles. Then, innovative variations of these methods were developed to combine their respective advantages in a one-step extraction: Static headspace with multiple SPME fibers (S-HS-MultiSPME), Dynamic headspace with multiple SPME fibers (D-HS-MultiSPME) and dynamic headspace with multiple SPME fibers and Tenax (D-HS-MultiSPME/Tenax). The extracts were analyzed by gas chromatography coupled with mass spectrometric and flam...
Application of vacuum solid-phase microextraction for the analysis of semi-hard cheese volatiles
European Food Research and Technology, 2020
Solid-phase microextraction (SPME) is a well-established technique in the analysis of food volatile compounds, usually performed for qualitative analysis. This paper presents an elaboration of conditions for SPME analysis of main volatile compounds in hard cheese and an evaluation of suitability of vacuum to improve the transfer of volatile compounds towards SPME fiber. Compounds representing the main groups of hard cheese volatiles were investigated: 1-pentanol, butanoic acid, 2,3-butanedione and 2-heptanone. Parameters for SPME extraction (temperature, water, sodium carbonate addition, time, vacuum) were evaluated. Application of vacuum had a positive effect on all analytes when extraction was performed from water, but in the cheese matrix the effect was significant only for butanoic acid. Extraction time was the most significant factor for extraction efficiency in examined cheeses, while temperature had a minor effect on the amount of extracted volatiles. The method was applied o...
Comparison of Automated Extraction Techniques for Volatile Analysis of Whole Milk Powder
Foods
Volatile profiling of whole milk powder is valuable for obtaining information on product quality, adulteration, legislation, shelf life, and aroma. For routine analysis, automated solventless volatile extraction techniques are favored due their simplicity and versatility, however no single extraction technique can provide a complete volatile profile due to inherent chemical bias. This study was undertaken to compare and contrast the performance of headspace solid phase microextraction, thermal desorption, and HiSorb (a sorptive extraction technique in both headspace and direct immersion modes) for the volatile analysis of whole milk powder by gas chromatography mass spectrometry. Overall, 85 unique volatiles were recovered and identified, with 80 extracted and identified using a non-polar gas chromatography column, compared to 54 extracted, and identified using a polar gas chromatography column. The impact of salting out was minimal in comparison to gas chromatography column polarit...
A new technique for analyzing the overall full range of volatile to semi-volatile organic compounds in high alcohol containing beverages using Vacuum Assisted Sorbent Extraction (VASE) in headspace paired with GCMS analysis is presented. A cartridge containing approximately 70mg of Tenax is placed into a sample vial containing either neat or diluted sample containing a high amount of alcohol. A vacuum tight interface allows the vial headspace to be evacuated to less than 0.01 atmospheres, or at least to the point where an aqueous mixture starts to boil at 25°C. The vacuum is only applied for the time it takes to evacuate the vial, about 15-30 seconds depending on vial size. The vial remains under vacuum after removal of the vacuum source, creating a closed system where faster diffusion from the sample/headspace boundary layer to the adsorbent enhances rates of extraction for both low and higher volatility compounds. Heavy volatile compounds with low vapor pressures which have little to no response by classical SPME are extracted 10-50x more efficiently. Unlike dynamic headspace, which uses an inert gas to sweep the volatiles of a sample through the adsorbent bed to concentrate and trap analytes, VASE is performed statically. VASE allows the sample and headspace to come to an equilibrium in a closed system, causing analytes to diffuse onto and collect at the very front of the adsorbent bed. Therefore, VASE achieves a much better recovery of heavier compounds while eliminating the common carryover issues. Once placed under vacuum, the extraction time ranges from minutes to hours until equilibrium between the sample and headspace is reached to produce complete, reproducible extractions. This helps to prevent changes in extraction efficiency when small differences in the sample matrix occur. Additionally, using a packed adsorbent trap for VASE has the advantage of providing 100x more capacity than a GC capillary columns, allowing split injections of 50:1 or more to achieve rapid injection rates while still maximizing the amount that can be loaded onto capillary a GCMS systems for maximum sensitivity and optimum detection limits. In the case of alcoholic beverages, an increased phase ratio is extremely important in dealing with the high affinity of most odor and flavor compounds to the high alcohol containing matrix (up to 40% alcohol by volume). Data is presented showing rum, whiskey, and wine samples analyzed using VASE, with and without the addition of water or a saturated sodium sulfate solution to determine the optimum approach for recovering volatile to semi-volatile compounds in the sample. Calibration curves of trace level contaminants in wine are also presented showing calibrations from 0.1 to 20 ng/L for Trichloroanisoles, Tribromoanisole, Geosmin, and 2-Methylisoborneol, using Geosmin-d3 as the internal standard. Consistent recovery of these compounds in spiked and non-spiked drinking water and wine demonstrated the ability to perform measurements in matrices with varied complexity and affinity for the target analytes. The results show the extensive range of compounds extracted using VASE. This demonstrates its potential as a sensitive and routine method for examining aroma compounds relating to flavor analysis and regulated contaminants such as trichloroanisoles and phthalates in alcoholic beverages.
2018
Biological matrices of mammals contain many volatile compounds which can act as specific chemical cues for congeners modifying their behavior or their physiological parameters. Gas-chromatography (GC) can be used to assess such matrices, however, this is a challenging technique because of low concentrations of highly volatile analytes. Thus, an extraction technique that (i) preserves the original profile of the volatile compounds, and (ii) concentrates the analytes is required. Headspace extraction methods, such as headspace solid phase micro-extraction (HS-SPME) or dynamic headspace (DHS), show many advantages. Therefore, they are promising methods for the analyses of biological matrices. In this study, DHS was compared by using two sorbent cartridges, and HS-SPME was performed for the exploration of human milk composition. Volatile compounds of pooled breast milk samples were extracted by HS-SPME using a Car/PDMS fiber, by DHS associated to Tenax® or Bio-monitoring sorbent tubes. ...