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Use of Sorbent-Based Vacuum Extraction for Determination of Volatile Phenols in Beer


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Abstract

A novel method based on vacuum-assisted sorbent extraction (VASE) used with gas chromatography-mass spectrometry (GCMS) for isolation of volatile phenols was described. The method is based on extraction of analytes into sorbent traps (sorbent pen) filled with Tenax in a vacuum system—vials with traps from which air was evaluated. The method was applied for extraction of volatile phenols from aqueous matrix and smoked beer was used as a food example. Methyl-, dimethyl-, and trimethylphenols, along with 4-ethylphenol, 4-methylguaiacol, 4-ethylguaiacol, 4-propylguaiacol, and eugenol, were used in method development. Optimal extraction parameters were elaborated. For the analysis of volatile phenols in beer matrix, the method was characterized with satisfactory linearity (r2 ≥ 0.99) in a range of 0.005–0.5 mg/L. Limits of detection (LODs) for analyzed compounds ranged from 0.0006 to 0.018 mg/L and repeatability for majority of compounds was < 5% for a single trap extraction. The detected volatile phenols in beer samples ranged from 0.003 to 0.672 mg/L.­­­

 

Solvent Free Extraction Technique for Determination of Semi-Volatile Organic Compounds in Water Samples by EPA Method 8270


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Overview

The need for accurate monitoring of SVOCs in water samples using methods such as US EPA Method 8270 continues to grow in importance as the comprehension of their adverse effects on human health evolves. Improvements in analytical technology for accurate determination down to sub-PPB levels is critical to obtain the most comprehensive monitoring possible. Current techniques for extraction of base/neutral/acid SVOCs include solvent extraction and separatory funnel extraction, however these methods require many steps and environmentally unfriendly solvents. Additionally, there are many analytical challenges due to matrix interferences, contamination, and the broad range of chemical properties.

 

7650HS-CTS Analyzer


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7650HS-CTS Analyzer

The most versatile & sensitive static headspace system available.

The all-new 7650HS-CTS is the only commercially available solution that can quantify the consumer experience by taking an equilibrium “snapshot” of the headspace to accurately determine its composition from the lightest through the heaviest compounds. The 7650HS-CTS is truly unique as it is the industries “only” system that uses multiple stages of true capillary columns to perform headspace preconcentration. This patent pending technology is creating a SPME like sampling, but in a way that obtains complete recovery of the lightest to the heaviest headspace compounds with virtually no reactive losses and no carryover.

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When sampling a large volume at static equilibrium, all compounds are quantitatively recovered at the same concentration as experienced by the consumer, giving the flavor or fragrance Chemist remarkable insight into exactly what the consumer is smelling, at exactly the same relative concentrations. This avoids the reactivity and carryover associated with other thermal desorption systems on the market that still use packed traps to concentrate the sample.

The 7650HS-CTS supports sample analysis via large and small volume static headspace (1–1000cc) to accommodate a wide range of concentrations with quantitative recovery of compounds with boiling points from -50°C to >400°C. The 7650HS-CTS maximizes throughput while offering state-of-the-art performance in quantitative accuracy, sensitivity, and low carryover. The 7650HS-CTS resides to the right of the GCMS system, with multiple trays supporting several different sample container sizes. The 7650HS-CTS is compatible with the latest 1D/2D chromatographic solutions for food, flavor, aroma, product testing, environmental, and clinical applications.

Say Goodbye to Packed Traps

Generate beautiful Chromatograms! Sharper peaks than even before.

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Featured Chromatograms

“Classical” SPME vs On-Column Extraction

Classical SPME (Solid Phase Microextraction) uses passive diffusion to collect and partition headspace compounds onto a coated fiber/lament placed directly in the sample headspace. The time required for each analyte to come to equilibrium with a SPME fiber depends on individual vapor pressures and coating affinities. Lighter, more volatile compounds have much less phase affinity than heavier compounds. As a result, true headspace concentrations fail to be accurately analyzed and reported whenever the SPME fiber headspace exposures exceed the equilibration time of the most volatile analytes – which may occur in just a few seconds!

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Unfortunately, it can take 10–90 minutes to collect enough of the heavier aroma compounds to allow detection by GCMS. This results in the heavier compounds being over-represented relative to lighter compounds by several hundred fold. This fact alone makes passive SPME a qualitative, rather than a quantitative technique for the determination of headspace composition. In addition, the extent of partitioning into a SPME fiber for any particular analyte is dependent on temperature and sample matrix variations. Upon desorption, the SPME lament is placed directly into a hot injector – which may thermally alter the sample composition. Capillary Column Trapping with the 7650HS-CTS utilizes multiple capillary columns with increasing strength to recover all relevant compounds, allowing a known volume to be sampled for quantitative determination of headspace composition. Water and air pass through the traps almost unretained, eliminating the interferences associated with improper management of the matrix.

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Flavor & Food / Beverage Analysis

The 7650HS-CTS performs Large Volume Static Headspace under equilibrium conditions. Samples are allowed to come to equilibrium over 30-60 minutes, with optional warming in a mixing oven prior to extracting the headspace into the capillary traps. Aroma Significant Compounds (ASC), are easily identified with a small volume injection (10cc) using GC/Olfactometry. The mass spectrum of detected aromas can then be obtained by analyzing a larger volume of headspace (50–1000cc). Only those aromas detected within the small volume GC/O analysis need be identified, significantly reducing aroma characterization complexity. High ethanol concentrations are managed either by flushing additional gas through the column traps in the forward flow direction, or by using a solvent delay in the mass spectrometer to let the ethanol clear the GC column prior to commencing with data collection.

7650-HS-CTS | The most versatile & sensitive static headspace system available

Direct Capillary Column Trapping

Capillary columns perform the sample enrichment, improving quantitative accuracy.

Sample Vial Sizes from 20 to 1000cc

Optimal sensitivity and statistical accuracy

Micro-QT Septumless Sample Interface

Gas-tight seal down to full vacuum.

Heat Samples from Ambient to 100°C

Recovers Thermally Labile Compounds

Analyze compounds containing sulfur, phosphorous, nitrogen.

Extremely Low Carryover

Capillary column traps have far less carryover relative to packed traps

Supports All Balance Gas Compositions

(Air, nitrogen, CO2 , H2 , He, methane, mixture).

Easily Handles High Ethanol Matrices

Sample from 1 to 1000cc

Maximize GCMS dynamic range.

Liquid Nitrogen Focuser

Improves separation and the resolution of compounds boiling below 50°C.

Mixing and Agitating Oven

Rapid heating and sample equilibration.

Advanced Water Management

Capillary column traps have virtually zero water retention.

The 7650HS-CTS | One Instrument. Endless Possibilities.

Exclusive Vacuum-Tight Sample Interface

Headspace extraction is performed using Entech’s unique septumless micro-seal for repeated gas-tight sample access. This approach completely avoids the use of septa, preventing coring and compound absorption found with these simple rubber seals. The micro-seal allows samples to be stored under vacuum for enhanced equilibration rates.

Multi-Capillary Column Trapping System

The most advanced and quantitative high sensitivity static headspace solution available. It traps all compounds boiling from -50°C to >400°C, except for water vapor which is almost unretained. Thermally labile, GC compatible compounds are virtually all recovered, because the headspace goes directly to capillary column traps, followed by backflushing right onto the GC analytical column.

DESCRIPTIONPART#QTY
7650HS-CTS Bundle (120VAC/60Hz)*7650HS-CTS-B011
11 Position 500mL Wide-Mouth LVSH Tray HS-ST280-011HS-ST280-0111
10 Position 1L Wide-Mouth LVSH TrayHS-LT384-0101
500mL LVSH Vials (box of 12)39-75500W1
Vial Caps for 500mL vials (high temp)39-76850HS12
Silonite™ Liners for 500mL vialsHS-76050012
1L LVSH Vials (box of 12)39-75L1W1
Vials Caps for 1L vials (high temp)39-76894HS12
Silonite™ Liners for 1L vialsHS-76100012
Micro-QT™ ValveHS-LVSH-SMS24
Mixing OvenHS-OVEN-407-1M1
*Use part #7650HS-CTS-HV-B01 for 220-240VAC/50Hz

7650HS-CTS Analyzer

with On-Column Extraction (Trace Level Headspace)

The 7650-HS uses Entech’s exclusive Multi-Capillary column trapping system (MCCTS) that provides better “true” characterization of trace headspace concentrations than any other headspace technique. A 3-stage trapping system features an initial thick-film GC column that performs On-Column Extraction to “absorb” semi-volatile compounds, allowing them to be simply “reverse flushed” off the thick-film column and onto the analytical column in the GC for better recovery of both high boilers and thermally labile compounds.

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Sorbent Pens for Headspace Analysis by VASE – Vacuum Assisted Sorbent Extraction


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Headspace Sorbent Pens™ & VASE

Ultimate Extraction Power For Next Generation Headspace Analysis

100's of Applications!

Flavors & Aromas

Food Safety

Pharmaceuticals

Water Testing

Clinical Diagnosis

Introducing Entech’s new solvent-free Sorbent Pen™ headspace solution, the most versatile extraction and sample preconcentration technology available for GC and GC-MS systems. Sorbent Pens combine the features of SPME and classical ¼” adsorbent traps in a design with far more flexibility and enhanced performance. The Sorbent Pen™ uses an entirely new approach for sample extraction. Direct insertion of the Sorbent Pen™ through a gas tight liner in the vial allows for a new technique called “Vacuum Assisted Sorbent Extraction”, or VASE, to recover a far wider range of compounds than ever before. Drawing a vacuum of 30x below atmosphere through the pen’s unique micro-valve allows for a more thorough and rapid equilibration to occur in the vial headspace.  With 150x the phase loading of SPME, and a durable, ultra-inert Silonite treated steel enclosure, the Sorbent Pen can perform exhaustive extraction and more fully recover light to heavy compounds with improved sensitivity and reproducibility.

VASE offers a tremendous advantage over other extraction techniques that perform extractions at atmospheric pressure where diffusion rates are suppressed. Sorbent Pens™ perform sample enrichment offline from a GCMS, allowing all samples to extract simultaneously and for longer periods of time. This approach results in high throughput while yielding a more complete and reproducible extraction for more sensitive and quantitative measurements. The low cost 5800 Sorbent Pen™ Desorption Unit (5800 SPDU) makes this exciting new technique both affordable and practical for virtually any laboratory’s budget. Upgrade to 90 sample automation with the Entech  7850 Autosampler for the ultimate in laboratory productivity. Join the Sorbent Pen™ movement and take advantage of the next generation in GCMS sample preparation!

  • Highly reproducible. Very Low Carryover.

  • Durable – hundreds of injections.

  • Operates at or near equilibrium to improve sensitivity and quantitative accuracy.

  • Perform exhaustive vacuum extraction of VOCs through SVOCs.

  • Unlike SPME, outer sheath minimizes exposure to aerosols formed during agitation.

  • See taints, odors, additives, flavors & fragrances at levels below previously possible.

  • Faster injection rates produce better chromatography / less thermal degradation.

  • Rapid injections without cryogen or electronic cooling.

  • Usually requires no secondary bakeout/cleanup.

  • Sample up to 2 days under vacuum for unsurpassed SVOC recovery.

  • Sample at elevated or sub-ambient temperatures as needed.

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  • Products

  • Sorbent Pen™ Desorption Unit
  • 5800 Liner for HSP & DSP Sorbent Pens™
  • Tenax HS Sorbent Pen™
  • Blank HS Sorbent Pen™
  • 30 Position Tray Headspace Sorbent Pens™
  • Silonite coated Pre-Column (0.6m, 1mm ID, No Film)
  • 2-Stage Oilless Diaphragm Pump
  • Sorbent Pen™ Thermal Conditioner
  • 30-0”Hg Vacuum Test Gauge
  • 5600 Sorbent Pen™ Extraction System
  • 30 Position Tray for 40mL Vials
  • 40mL Clear Vials
  • Lid for 40/60mL Vials/125mL Bottles
  • Low Bleed Blue Viton O-Rings
  • Caps for 40/60mL Vials/125mL Bottles
  • Vial Evacuation Unit

Headspace Sorbent™ Pen Brochure

Introducing Entech’s exciting new Sorbent Pen™ technology. The most versatile extraction and sample preconcentration technology available for GC and GCMS. Sorbent Penscombine the features of SPME and classical ¼” adsorbent traps in a design with far more flexibility and enhanced performance.

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Entech 2018 Catalog


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This is the complete Entech 2018 Catalog. You can download the PDF or use our Flipbook viewer (below) for a smoother experience. Please note that not all sampling products are included. The Entech store is the best place to find photos and descriptions of every product we carry.

 

7650HS-CTS Large Volume Static Headspace Brochure


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The 7650HS-CTS is Entech’s latest GCMS headspace sample preparation system that recovers a wider range of compounds at lower concentrations than any other headspace system. The 7650HS-CTS supports sample analysis via large and small volume static headspace (1-1000cc) to accommodate a wide range of concentrations with quantitative recovery of compounds with boiling points from -70C to >+400 C. The 7650HS-CTS maximizes throughput, while offering state-of-the-art performance in quantitative accuracy, sensitivity, and low carryover. The 7650 sits to the right of your GCMS , with an advanced preconcentration trapping system that sits on top of the GC just inches away from the GC column to ensure complete sample transfer to the column. The 7650HS-CTS is fully 1D/2D GC compatible, supporting the latest food, flavor, aroma, product testing, environmental and clinical applications.

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