Gerstel: Intelligent Automation for GC/MS and LC.MS

Stir Bar Sorptive Extraction - SBSE - Twister


A Novel Extraction Technique for Aqueous Samples: Stir Bar Sorptive Extraction featured

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Keywords: Stir Bar Sorptive Extraction - SBSE, GERSTEL Twister

ABSTRACT

A new approach using stir bars coated with PDMS was recently developed. In this approach, 50-300 μL PDMS coatings are used. Consequently, the sensitivity is increased by a factor of 100 to 1000. Complete recovery is possible for solutes with k(o/w) larger than 500. Solutes with k(o/w) from 10 to 500 can also be analyzed using calibration as is done in SPME. This technique is called stir bar sorptive extraction (SBSE). PDMS coated stir bars are now commercially available(TwisterTM, GERSTEL). Magnetic stirring rods are incorporated in a glass jacket and coated with a layer of PDMS.


Stir Bar Sorptive Extraction (SBSE) applied to Environmental Aqueous Samples

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Keywords: Stir Bar Sorptive Extraction - SBSE, GERSTEL Twister, Environmental Analyses

ABSTRACT

For the analysis of organic compounds in aqueous environmental matrices several sample preparation methods are used. Volatile organic compounds can be analyzed using (static) headspace, purge and trap or liquid-liquid extraction. Semi-volatiles are analyzed after liquid-liquid extraction or solid phase extraction (SPE). During the past years, miniaturization has become a dominant trend in analytical chemistry. Typical examples of miniaturization in sample preparation techniques are micro liquid-liquid extraction (in-vial extraction), ambient static headspace and disk cartridge SPE. In combination with state-of-the-art analytical instrumentation, this resulted in faster analysis, higher sample throughput, lower solvent consumption, less manpower in sample preparation while maintaining or even improving sensitivity.


Corkiness in Wine - Trace Analysis of 2,4,6-Trichloroanisole by Stir Bar Sorptive Extraction (SBSE) and Thermal Desorption GC/MS

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Keywords: Twister, Stir Bar Sorptive Extraction SBSE, 2,4,6-Trichloroanisole, Wine, Off-Flavor, Thermal Desorption, Capillary GC/MS, Ultra-Trace Analysis

ABSTRACT

2,4,6-Trichloroanisole (TCA) is well known as being the main cause for corkiness in wine. Its extremely low odor threshold usually mandates 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 determination of 2,4,6-Trichloroanisole in wine without the necessity of any classical sample preparation. Calibration curves will show linear responses over more than three magnitudes down to 10 ng/L in full scan and below 1 ng/L in selected ion monitoring.


Flavor Profiling of Beverages by Stir Bar Sorptive Extraction (SBSE) and Thermal Desorption GC/MS/PFPD

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Keywords: Beverage, Flavor, Stir Bar Sorptive Extraction SBSE, Twister, Thermal Desorption

ABSTRACT

The analysis of flavor compounds in beverages such as coffee, tea, soft drinks and alcoholic beverages usually requires cumbersome sample preparation steps such as li quid/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 is restricted to volatile compounds and therefore characterize compounds that contribute to the aroma/smell of a sample, not flavor/taste. The sensitivity of solid phase microextraction (SPME) is limited by the small amount of sorptive material that can be coated on the fibers. A new extraction technique, Stir Bar Sorptive Extraction (SBSE), recently described by Pat Sandra et.al., that overcomes the major problems with classical extraction techniques is applied in this paper. With this technique, a small stir bar (10-20mm length, 1.3mm OD) is coated with polydimethylsiloxane (1mm d.f.), placed directly in the sample, and stirred for about 1 hour. During this time, analytes are extracted into the PDMS phase, which acts as an immobilized liquid phase. The stir bar is removed, rinsed with distilled water, and placed into a thermal desorption unit. Due to the hydrophobic character of PDMS, a drying step is not necessary. Heating the stir bar releases the extracted compounds into a GC/MS system for subsequent analysis with very low detection limits (parts per trillion).


Determination of Flavor and Off Flavor Compounds in Dairy Products using Stir Bar Sorptive Extraction (SBSE) and Thermal Desorption GC/MSD/PFPD

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Keywords: Determination of Flavor and Off Flavor Compounds in Dairy Products using Stir Bar Sorptive Extraction (SBSE) and Thermal Desorption GC/MSD/PFPD

ABSTRACT

The analysis of flavor compounds in dairy products such as milk, cream, yogurt 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 organic solvents, but their analyte range is restricted to volatile compounds and therefore characterize compounds that contribute to the aroma/smell of a sample, not flavor/taste. In addition heating of the sample should be avoided since this would lead to reaction products which dramatically modify the flavor and taste of any dairy product. The sensitivity of solid phase microextraction (SPME) is limited by the small amount of sorptive material that can be coated on the fibers. A new extraction technique, Stir Bar Sorptive Extraction (SBSE), that overcomes the major problems with classical extraction techniques is applied in this paper. With this technique, a small stir bar is coated with polydimethylsiloxane, placed directly in the sample, and stirred for about 1 hour. During this time, analytes are extracted into the PDMS phase, which acts as an immobilized liquid phase. The stir bar is removed, rinsed with distilled water, and placed into a thermal desorption unit. Due to the hydrophobic character of PDMS, a drying step is not necessary. Heating the stir bar releases the extracted compounds into a GC/MS system for sub sequent analysis with very low detection limits (parts per trillion).


Stir Bar Sorptive Extraction: Enhancing Selectivity of the PDMS Phase

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Keywords: Twister, SBSE, Solvent Back extraction, pH Adjustment

ABSTRACT

Strategies are shown that provide additional control of the partitioning of analytes into the PDMS phase during SBSE. Parameters such as sample pH, salt content and the presence of solvents during extraction can be used to enhance the extraction efficiency of a range of analytes including polar compounds. The very high capacity of the SBSE phase allows the use of solvent back extraction prior to thermal desorption to selectively reduce the background interference from complex sample matrices.


Elimination of Polar Matrix Components Prior to GC Analysis using Stir Bar Sorptive Extraction (SBSE)

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Keywords: Twister, SBSE, Fragrance, Acetic acid, Ethanol, Glycol, Detergent, Emulsion

ABSTRACT

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. Stir bar sorptive extraction using a polydimethylsiloxane (PDMS) phase on the stir bar prior to GC analysis can eliminate major interference from these polar matrix components. The PDMS selectively extracts non-polar analytes, discriminating against the polar matrix components present in the sample at even percent levels or higher. Samples that contain high levels of interfering compounds like surfactants and emulsifiers that usually form emulsions when attempting organic solvent extractions can be analyzed directly by SBSE. Examples include separation of flavor and fragrance components in balsamic vinegar and alcoholic beverages, and analysis of fragrances and other additives in consumer products like soaps and detergents. Trace additive analysis in new and used antifreeze further demonstrates the versatility of SBSE for sample preparation prior to GC analysis.


Elucidation of the Hoppy Aroma in Beers by Stir Bar and Headspace Sorptive Extraction followed by Thermal Desorption - GC/MS/PFPD

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Keywords: Stir Bar Sorptive Extraction, SBSE, Beer, Hops

ABSTRACT

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, namely stir bar sorptive extraction (SBSE) and headspace sorptive extraction (HSSE) were evaluated for the enrichment of hop derived solutes in beers.


The Analysis of the Bitter and Other Flavour Compounds in Beer and Wort by Stir Bar Sorptive Extraction (SBSE) Followed by HPLC

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Keywords: Stir Bar Sorptive Extraction, SBSE, Beer, Wort

ABSTRACT

A new sample preparation technique - Stir Bar Sorptive Extraction (SBSE) was evaluated for the enrichment of hop-derived solutes in wort and beer. SBSE offers an effective, easy-handling and low cost opportunity for the isolation of organic solutes from aqueous matrices. A small stir bar, coated with polydimethylsiloxane is placed directly in the sample and stirred for about an hour. After sampling, the stir bar is placed in a thermal desorption unit for subsequent GC separation under mild conditions. Several hop-derived solutes can be elucidated and identified in this way. Alternatively, the stir bar can be desorbed by a liquid followed by HPLC analysis. This allows analysis of some of the thermally stable hop derived solutes. Both approaches are complementary in nature and give a quite complete profile of the hoppy flavor in beer. The SBSE approach has also been compared to the classical SPE-HPLC technique.


Comparison of the Sensitivity of Solid Phase MicroExtraction (SPME) and Stir Bar Sorptive Extraction (SBSE) for the Determination of Polycyclic Aromatic Hydrocarbons (PAHs) in Water and Soil Samples

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Keywords: PAH, SPME, Stir Bar Sorptive Extraction, SBSE, GERSTEL Twister, Thermal desorption, GC-MS, PCB

ABSTRACT

Two extraction techniques that avoid solvent consumption and cut down the sample preparation to a minimum - Solid Phase MicroExtraction (SPME) and Stir Bar Sorptive Extraction (SBSE) – were compared on the basis of their reproducibility and sensitivity for 16 US EPA PAH compounds.


Preliminary Studies on the Recovery of SVOC from Soil using Pressurized Fluid Extraction with Methanol/Water

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Keywords: Soil Analysis, EPA SW-846, Method 8270, Stir Bar Sorptive Extraction, SBSE, SVOC, Accelerated Solvent Extraction, ASE

ABSTRACT

The analysis of contaminated soil and sludge samples for semi-volatile organic compounds (SVOC) has traditionally been performed using gas chromatography/mass spectrometry (GC/MS) (EPA SW-846, Method 8270). This method relies on the extraction of contaminants from the samples utilizing a variety of organic and chlorinated solvents. This study shows the effective use of a Dionex Accelerated Solvent Extractor 200 (ASE) along with Stir Bar Sorptive Extraction (SBSE) with methanol replacing the undesirable chlorinated solvents.


Semi-Automated Stir Bar Sorptive Extraction (SBSE) in Combination with HPLC - Fluorescence Detection for the Determination of Polycyclic Aromatic Hydrocarbons in Water

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Keywords: Stir Bar Sorptive Extraction, SBSE, Twister, PAHs

ABSTRACT

 In this study we describe the possibility of automation of the SBSE desorption step with direct transfer of the liquid extract to HPLC by use of the GERSTEL- MultiPurpose autosampler MPS (Twister Back-Extraction). For this purpose the MPS was equipped with a temperature programmable agitator and a special software. Using this procedure, after extraction of water samples by SBSE, the only manual step is the removal of stir bars from the sample vial and transfer to 250 μL glass inserts placed inside 2 mL autosampler vials. The MPS then adds the ACN/water mixture to the stir bar, transports the vial to the agitator, where it is agitated at a defined temperature during the preset desorption time and finally withdraws an aliquot of the extract, which is injected into the HPLC.


Stir Bar Sorptive Extraction from Food Simulating Solvents: Preliminary Studies

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Keywords: Food packaging, Food simulants, Stir Bar Sorptive Extraction. SBSE

ABSTRACT

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 in the 1-50 ppb range. Since determination of trace component migration into complex food matrices is extremely difficult if not impossible, the FDA has established acceptable food simulating solvents to use for migration testing. These solvents (water, 3% acetic acid, 10% ethanol and 95% ethanol) comprise much simpler matrices and minimize the potential for interference. Simpler matrix notwithstanding, developing reliable analytical methods for low ppb LOD can be a formidable challenge. Stir Bar Sorptive Extraction (SBSE) followed by thermal desorption GC has been shown to provide excellent detection limits for non-polar analytes in the low ppb - ppt range. Polar matrix components such as ethanol and acetic acid do not partition into the PDMS phase on the stir bar, minimizing potential interference during analysis. This technique is therefore compatible with the FDA specified food simulating solvents. Model compounds spanning a wide polarity range were spiked into the food simulating solvents, extracted by SBSE using GERSTEL Twister stir bars, and recovered by thermal desorption GC. The presence of solvents in the sample matrix reduced analyte recovery in the stir bar, with the largest effect seen for compounds with octanol:water partition coefficients less than 500. Since partitioning into the PDMS phase is proportional to the octanol/water partition coefficient and predictable, these results provide guidelines for the types and polarities of analytes amenable to this technique.


Stir Bar Sorptive Extraction: Capacity and Competition Effects

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Keywords: Stir Bar Sorptive Extraction, SBSE, SPME, Capacity

ABSTRACT

The determination of volatile and semi-volatile analytes 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 and waste water analysis, beverages and other consumer products.  In this study physical capacity of the GERSTEL Twister stir bar was determined gravimetrically by concentrating hexadecane from aqueous isopropanol solutions. Under optimal conditions, the stir bar absorbed milligram quantities of hexadecane. From a practical perspective, the highest analyte concentration that still provides a linear calibration response could be defined as the working capacity of the stir bar. For typical analytes, this upper limit was found to be in the ppm range. To assess competition and displacement effects, model compounds including a pesticide mix and methyl esters were extracted from water with Twister or SPME in the presence of up to 5 ppm limonene. Under these conditions, the most polar analytes showed the greatest reduction in peak area when extracted with SPME. Detection limits determined for model compounds showed a 10 to 25-fold advantage of the increased capacity of the Twister phase compared to SPME.


Stir Bar Sorptive Extraction: Recovery of Organic Acids and Amines

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Keywords: Stir Bar Sorptive Extraction, SBE, of Organic Acids, Amines

ABSTRACT

The determination of volatile and semi-volatile 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, consumer products and environmental. It has been shown to be simple, sensitive, quantitative, and can often eliminate cumbersome solvent extraction or other sample preparation steps. Efficiency of partitioning into the polydimethylsiloxane (PDMS) phase on the stir bar can be predicted based on the known analyte partitioning between octanol and water as described by the octanol-water partition coefficient Kow. This prediction usually works well for most compounds, but can overestimate recovery of ionizable compounds like organic acids and amines since only the neutral form can be extracted into the bar. SBSE of organic acids and amines is evaluated from simple aqueous solutions as well as at pH extremes. Extraction behavior as a function of pH is correlated to published compound dissociation constants. Strategies to enhance extraction efficiency of ionizable compounds are discussed.


Coupling Retention Time Locked Methods and Libraries to Automated SPME or SBSE for Analysis of Flavors and Fragrances

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Keywords: Flavors, GC/MS, Retention Time Locking, SPME, SBSE

ABSTRACT

Analysis of foods, flavors and fragrances is commonly done by capillary gas chromatography coupled to a range of detectors depending on the particular needs of the analysis. Using Retention Time Locked (RTL) methods can facilitate the transfer from one instrument to another, particularly if different detectors (eg. MSD and FID) are used. Although liquid or headspace injection methods are often used for these analyses, difficult and time-consuming sample preparation steps, or lack of sensitivity are commonly encountered. Automated Solid Phase Microextraction (SPME) or Stir Bar Sorptive Extraction (SBSE) can often provide substantial improvements to existing methods. In this contribution, we illustrate the use of RTL methods and the Agilent RTL Flavor Library when the GERSTEL MPS 2 autosampler is used to automate either SPME or SBSE as sample extraction and introduction technique. Procedures are given for calibrating the GC method using either technique. RTL methods created for both sample introduction techniques could be moved from a GC/FID to a GC-MSD system with different column head pressure requirements. Calibrated RTL SPME or SBSE methods were then used to analyze several sample types that otherwise would pose significant matrix interference or detection limit issues. Example chromatograms with identifications based on the RTL flavor library are given.


Multi-Residue Method for Determination of 85 Pesticides in Vegetables, Fruits and Green Tea by Stir Bar Sorptive Extraction and Thermal Desorption GC-MS

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Keywords: Multi-residue Method, Pesticides, Vegetables, Fruits, Green Tea, Stir Bar Sorptive Extraction, SBSE, GC/MS

ABSTRACT

A multi-residue method to determine five groups of 85 pesticides - chlorinated, carbamate, phosphorous, pyrethroid and others - in vegetables, fruits and green tea has been developed using stir bar sorptive extraction (SBSE) coupled to thermal desorption and retention time locked (RTL) GC-MS. Pre-extraction with methanol and dilution with water prior to SBSE (60 min) were performed. Dilution of methanol extract for SBSE was examined to obtain high sensitivity and to compensate the effect of adsorption to the glass wall of extraction vessel and to sample matrix for the compounds with high log Ko/w values (e.g. pyrethroid). The methanol extracts were diluted twofold and fivefold, and were simultaneously SBSE enriched. The two stir bars were placed in a single glass thermal desorption liner and were simultaneously desorbed. The versatility of the method was exhibited by its good linearity (4-100 μg/kg, r2 >0.9900) for 66 pesticides and limit of detection (LOD: < 5 μg/kg) for most of the analytes. The method enables to determine pesticides at low μg/kg in tomato, cucumber, green soybeans, spinach, grape and green tea.


Multi-Residue Method for the Determination of Five Groups of Pesticides in Non-Fatty Food Samples by Dual Stir Bar Sorptive Extraction (Dual SBSE) and Thermal Desorption GC-MS

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Keywords: Stir Bar Sorptive Extraction, SBSE, Multi-residue Method, Pesticides, Vegetables, Fruits, Green Tea, GC/MS

ABSTRACT

A multi-residue method for determination of five groups of 85 pesticides - organochlorine, carbamate, organophosphorous, pyrethroid and others - in non-fatty food, e.g. vegetables, fruits and green tea is described. The method is based on stir bar sorptive extraction (SBSE) coupled to thermal desorption (TD) and retention time locked (RTL) GC/MS in scan mode. The method was applied to the determination of pesticides at low μg/kg levels in tomato, cucumber, green soybeans, spinach, grapes and green tea.


Application of Stir Bar Sorptive Extraction (SBSE) Coupled to Thermal Desorption GC/MS for Determination of Ultra-Trace Level Compounds in Aqueous Samples

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Keywords: Sample Preparation, Water, Stir Bar Sorptive Extraction, SBSE, Thermal Desorption, GC/MS

ABSTRACT

This paper applies SBSE coupled to thermal desorption (TD)-GC/MS to determine ultra-trace levels (sub-ng/L to ng/L) of compounds in aqueous samples.


Feasibility of Extraction and Quantitation of Δ9-Tetrahydrocannabinol in Body Fluids by Stir Bar Sorptive Extraction (SBSE) and GC/MS

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Keywords: Stir Bar Sorptive Extraction, SBSE, THC, GC/MS

ABSTRACT

This study demonstrates the feasibility of extracting THC from an aqueous matrix using Stir Bar Sorptive Extraction (SBSE) followed by thermal desorption into the injection port of a standard single quadrupole electron impact GC/MS to achieve detection limits less than 1.0 ng/mL. The specimen is diluted with water + methanol and extracted with a stir bar coated with a non-polar polydimethylsiloxane phase.


Evaluation of PDMS Based Extraction Techniques and GC-TOFMS for the Analysis of Off-flavor Chemicals in Beer

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Keywords: Beer, Off-flavors, Stir Bar Sorptive Extraction, SBSE, Headspace Sorptive Extraction, Twister®, GC-TOFMS

ABSTRACT

Various techniques employing polydimethylsiloxane (PDMS) as an extraction medium prior to GC-TOFMS analysis were investigated to measure off-flavors in aged beer. The techniques included stir bar sorptive extraction (SBSE), headspace sorptive extraction (HSSE), purge-and-trap (P&T) and closed-loop-stripping (CLS). SBSE appeared to provide the most accurate quantitation and was capable of detecting the most odor-active compounds. The peak deconvolution capability of the Leco Pegasus TOFMS was found critical to the detection and accurate quantitation of key off-flavor chemicals. Compared to fresh control beer, increases in furfural, furfuryl ethyl ether, furyl hydroxymethyl ketone, 2,4-dodecadienal, (E,E), benzeneacetic acid ethyl ester, ß-damascenone and 3-pyridinecarboxylic acid ethyl ester (a.k.a. nicotinic acid ethyl ester) were observed in beer samples incubated 12 wks at 30°C and increases in dimethyl disulfide, dimethyltrisulfide and benzeneacetaldehyde occurred in beer exposed to sunlight for 8 hrs.


Performance Evaluation of a Thermal Desorption System for Detection of Basic Drugs in Forensic Samples by GC/MS

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Keywords: Stir Bar Sorptive Extraction, SBSE, Basic Drugs, Forensic Analysis

ABSTRACT

Stir bar sorptive extraction (SBSE) is an innovative sample extraction technique that can be used to process blood, urine, and tissue samples for routine drug screening in the forensic toxicology laboratory. Case specimens containing drugs typically encountered in forensic samples were evaluated using SBSE and compared with a liquid/liquid extraction method followed by GC/MS analysis. This evaluation demonstrated that SBSE method worked equally as well as the routine extraction method for the detection of basic drugs in screening forensic samples.


Fast Screening of Pesticide Multiresidues in Aqueous Samples by Dual Stir Bar Sorptive Extraction (Dual SBSE) and Thermal Desorption – Fast GC/MS using a Low Thermal Mass Column Heater (LTM)

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Keywords: Dual Stir Bar Sorptive Extraction (Dual SBSE), Thermal Desorption, Fast GC/MS, Low Thermal Mass Column Heater, LTM, Pesticide Multiresidues, Aqueous Samples

ABSTRACT

A method for fast screening of pesticide multi-residues in aqueous samples using dual stir bar sorptive extraction (dual SBSE) - thermal desorption (TD) - fast GC/MS has been developed. Recovery of 82 pesticides – organochlorine, carbamate, organophosphorous, pyrethroid and others – for the SBSE. The method showed good linearity (r2 > 0.9900) and high sensitivity (limit of detection:< 10 ng/L) for most of the target pesticides. The method was applied to the determination of pesticides at ng/L levels in river water and brewed green tea.


A Novel Extraction Procedure for Stir Bar Sorptive Extraction (SBSE): Sequential SBSE for Uniform Enrichment of Organic Pollutants in Water Samples

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Keywords: Sequential Stir Bar Sorptive Extraction, Sequential SBSE, Thermal Desorption, GC/MS, Organic Pollutants, Water Analysis

ABSTRACT

A novel stir bar sorptive extraction (SBSE) procedure - "Sequential SBSE" was developed. Compared to conventional SBSE, sequential SBSE provides more uniform enrichment over the entire polarity/volatility range for organic pollutants at ultra-trace levels in water. Sequential SBSE consists of a SBSE performed sequentially on a 5-mL sample first without modifier using one stir bar, then on the same sample after addition of 30 % NaCl using a second stir bar. The method showed good linearity (r2 > 0.9900) and high sensitivity (limit of detection: < 10 ng/L) for most of the model compounds even with the scan mode in the MS. The method was successfully applied to screening of pesticides at ng/L level in river water samples.


Determination of Trace Components Using a Selectable 1D/2D GC-MS System based on Capillary Flow Technology and Heart-Cut Fraction Collection

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Keywords: Selectable 1D/2D GC/MS, SBSE, Food, Flavor, Fragrance

ABSTRACT

Identification of important trace components in complex samples like fragrances, natural products, petroleum fractions or polymers can be challenging. Achieving the mass on column and resolution necessary to locate and identify trace components using a single chromatographic separation can be difficult if not impossible. A selectable 1D/2D GC/MS configuration using Agilent capillary flow technology (CFT) and low thermal mass (LTM) GC column modules with dissimilar column phases was used to perform heartcutting 2D GC on two sample types. Stir Bar Sorptive Extraction was used as a solventless means to introduce sufficient mass of sample extract onto the pre-column of the multidimensional system. When additional mass is necessary to detect the analyte of interest in the second dimension separation, a selectable cryotrap after the pre-column can function as a fraction collector to accumulate fractions from many replicate chromatographic separations of the sample extract. Separation and identification of selected trace components from beverages and consumer products were used to demonstrate the effectiveness of this system. The main advantages of this configuration were the simple selection of one or two dimensional operation and the ability to collect multiple fractions to maximize signal from trace components in the second dimension.


Alternative Procedure for Extraction and Analysis of PAHs in Seafood by QuEChERS-SBSE-GC-MS

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Keywords: PAH, seafood, QuEChERS, SBSE, GERSTEL Twister

ABSTRACT

The Deepwater Horizon oil rig explosion and the subsequent massive oil spill was one of the worst offshore oil catastrophe in United States history and is and impacted fragile ecosystems, air and water quality, and food supplies.

Protecting humans from consuming foods contaminated with oil, while minimizing economical impacts for fisheries, is presenting several challenges. The current protocol for screening seafood harvested from the gulf is organoleptic testing followed by polycyclic aromatic hydrocarbons (PAHs) testing using NOAA Method 2004. It is generally thought that improved testing strategies will be needed to meet state screening requirements. A recent EPA Region 7 study has shown that Stir Bar Sorptive Extraction (SBSE) is an effective and fast technique for trace PAH determination in water. The goal of this study is to determine if using a QuEChERS solvent extraction in conjunction with SBSE can meet regulatory limits of detection and requirements established for precision and accuracy. Preliminary data show linear calibration for PAHs from 1-250 ng/g tissue in matrix matched extracts. Triplicate analyses estimates recoveries at 107 % ± 5 % RSD in fish tissue spiked with 2.5 or 25 ng/g PAH standards. It is also estimated that 40-60 homogenized samples/analyst/day can be analyzed using this improved method.


High Throughput Method for the Determination of PAHs in Seafood by QuEChERS-SBSE-GC-MS

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Keywords: PAH, seafood, QuEChERS, SBSE, GERSTEL Twister

ABSTRACT

This method uses a QuEChERS (quick, easy, cheap, effective, rugged, and safe) single-step acetonitrile (ACN) extraction and salting out liquid-liquid partitioning to extract PAHs from seafood tissue. Stir Bar Sorptive Extraction (SBSE) is then used as a combined cleanup and concentration step, eliminating organic acids and other polar and high molecular weight matrix components and providing a substantial concentration factor to easily meet regulatory limits of detection and requirements established for precision and accuracy for determination of PAHs in seafood tissue. In brief, 3g of a homogenized seafood tissue sample in water is extracted with ACN in a 50 mL centrifuge tube followed by addition of 6.0 g MgSO4 and 1.5 g sodium acetate which is shaken and centrifuged. A portion of the ACN extract (upper layer) is added to a 10 mL vial with 4 mL 0.1 M NaHCO3 and a GERSTEL Twister™ stir bar and stirred to extract and concentrate the PAHs. The Twister stir bar is transferred to a thermal desorption tube in an autosampler tray for analysis by gas chromatography/mass spectrometry (GC/MS).


Stir Bar Sorptive Extraction (SBSE) and GC/MS Determination of Polar and Non-polar Drugs and Pharmaceuticals in Post Mortem Brain Tissue

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Keywords: Drugs of abuse, Pharmaceuticals, Tissue samples, Stir Bar Sorptive Extraction, SBSE, Thermal Desorption

ABSTRACT

Stir Bar Sorptive Extraction (SBSE) is an innovative and efficient method for the extraction of drugs and pharmaceuticals from blood, urine and tissue samples in a forensic toxicology laboratory. As shown in this application note and earlier publications, SBSE is an effective screening tool for drugs and pharmaceuticals in biological fluids and tissue. The SBSE technique is easy to use and the method described in this publication is performed without additional use of organic solvents, centrifugation, or the liquid transfer steps that are normally necessary when performing liquid-liquid or solid-phase extraction.


Comparison of Three Different Phases for Stir Bar Sorptive Extraction of Whiskey, Wine and Fruit Juice

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Keywords: EG-Silicone, Twister, Stir Bar Sorptive Extraction, SBSE, Thermal Desorption, GC/MS, Whiskey, Wine, Juice

ABSTRACT

This paper describes a novel ethylene glycol (EG) and silicone based combined sorbent phase developed for stir bar sorptive extraction (SBSE) using the GERSTEL Twister™. EG-Silicone, polyacrylate (PA), and polydimethylsiloxane (PDMS) Twisters were used separately to perform SBSE on whisky, white wine and multivitamin juice in order to determine the usefulness of these phases for generating qualitative flavor profiles of beverages.


Qualitative Analysis of a Finished Personal Care Product using the GERSTEL MultiPurpose Sampler MPS configured with Multiple Sample Introduction Techniques

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Keywords: Thermal Desorption, Gas Chromatography, Mass Spectrometry, Stir Bar Sorptive Extraction, SBSE, GERSTEL Twister, Pyrolysis

ABSTRACT

This study shows the analysis of a commercially available personal care product using the GERSTEL MultiPurpose autosampler (MPS) configured with Thermal Desorption Unit (TDU), Cooled Injection System (CIS) PTV-type inlet, Dynamic Headspace (DHS) and pyrolysis (PYRO) modules in combination with a GC/MS system. Information regarding product composition can be obtained from the chromatographic profiles obtained from one analysis system using a variety of sample introduction techniques.


Determining Phenolic Compounds in Whiskey using Direct Large Volume Injection and Stir Bar Sorptive Extraction

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Keywords: Phenols, Whiskey, Capillary GC/MS, LVI, Solvent Vent, TDU, SBSE, Deconvolution

ABSTRACT

In this study, a method was developed for quantitative determination of seven phenolic compounds in scotch whisky. Two different whisky brands were analyzed by Stir Bar Sorptive Extraction (SBSE), based on novel EG-Silicone Twisters, combined with thermal desorption gas chromatography-mass spectrometry (TD-GC-MS). Direct Large Volume Injection (LVI) GC/MS was used as reference method. Optimized methods for LVI-GC/MS and SBSE-TD-GC/MS analysis were used for quantitative determination of the target compounds: phenol, o-,m-, and p-cresol, guaiacol, 4-ethylguaiacol, and 4-ethylphenol. Both methods were evaluated regarding linearity of calibration, reproducibility, and limits of detection (LOD), or limits of quantification (LOQ), for the target compounds. These values were calculated for pure whisky (40 % v/v, ethanol/water).


Rapid Automated Screening of Extractable Compounds in Materials for Food Packaging, Medical or Technical Purposes

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Keywords: Extractables, Leachables, Food Packaging Materials, Medical Materials, Automated Sample Preparation, Liquid Injection, Thermal Desorption, Gas Chromatography

ABSTRACT

This application note describes two automated methods for screening of extractable compounds from materials for food packaging, medical or technical purposes. The first method is based on automated liquid extraction performed by the GERSTEL MultiPurpose autosampler (MPS), the second involves thermal desorption of the material in question in the GERSTEL Thermal Desorption Unit (TDU). Both methods are suitable for gaining an overview of the quality and emission potential of a material and therefore useful in the search for a suitable packaging material. The methods deliver comparable qualitative results.


Qualitative Analysis of Coconut Water Products using Stir Bar Sorptive Extraction Combined with Thermal Desorption-GC/MS

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Keywords: Thermal Desorption, Gas Chromatography, Mass Spectrometry, Twister, Stir Bar Sorptive Extraction, SBSE

ABSTRACT

This study shows the analysis of several commercially available coconut water products using a GC/MS system equipped with a versatile autosampler and sample preparation robot capable of performing a wide range of standard sample introduction techniques including thermal desorption. A fast and efficient analysis method based on stir bar sorptive extraction (SBSE) in combination with thermal desorption-GC/MS was developed for the determination of flavor compounds, pesticides, antioxidants, compounds migration from packaging materials, and off-flavors in coconut water


Comparison of EG-Silicone SBSE and Derivatization PDMS SBSE for the Determination of Phenolic Compounds and Off-Flavors in Water

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Keywords: Stri Bar Sorptive Extraction, SBSE,GC/MS, Phenols, Off-flavor, Water

ABSTRACT

16 phenolic compounds along with typical drinking water off-flavor compounds like geosmin, 2-methylisoborneol(MIB), and 2,4,6-trichloroanisole (TCA) were determined using two different approaches: 1) In-situ derivatization with acetic anhydride followed by SBSE using the PDMS Twister and Thermal Desorption (TD)-GC/MS; 2) Direct SBSE without derivatization using the EG-Silicone Twister and subsequent TD-GC/MS. In the case of the EG-Silicone twister, derivatization is not required due to its higher affinity for polar compounds. Both methods were evaluated for the extraction of 0.01 to 1 μg/L of phenols from water samples.


Journal Reference for SBSE

Keywords: Stir Bar Sorptive Extraction, SBSE, Twister

ABSTRACT

Below is a list of publications on SBSE for your reference. These cannot be downloaded due to Copyright protection.

 

REVIEW: Stir bar sorptive extraction for trace analysis. David, F; Sandra, P. J. Chromatogr. A. 2007, 1152, 54-69

Stir bar sorptive extraction for the determination of pyrethroids in water samples - A comparison between thermal desorption in a dedicated thermal desorber, in a split/splitless inlet and by liquid desorption. Van Hoeck, E. David, F. Sandra, P. J. Chromatogr. A. 2007, 1157, 1-9

Stir bar sorptive extraction-thermal desorption-capillary GC-MS for profiling and target component analysis of pharmaceutical drugs in urine. Tienpont, B. et al. J. Pharm. Biomed. Anal. 2003, 32, 569-579.

Analysis of off-flavors in the aquatic environment by stir bar sorptive extraction-thermal desorption-capillary GC/MS olfactometry. Benanou, D; Acobas, F.; de Roubin, M. R.; David, F.; Sandra, P. Anal. Bioanal. Chem. 2003, 376, 69-77.

Analysis of 35 priority semivolatile compounds in water by stir bar sorptive extraction-thermal desorption-gas chromatography-mass spectrometry I. Method optimization. Leon, V. M. et al. J. Chromatogr. A. 2003, 999, 91-101.

Analysis of volatiles of malt whisky by solid-phase microextraction and stir bar sorptive extraction. Demyttenaere, J. C. R. et al. J. Chromatogr. A. 2003, 985, 221-232.

Application of stir sorptive extraction for wine analysis. Hayasaka, Y. et al. Anal. Bioanal. Chem. 2003, 375, 948-955

Analysis of polychlorinated biphenyls in food products. Ahmed, F. E. Trends Anal. Chem. 2003, 22, 170-185.

Determination of stale-flavor carbonyl compounds in beer by stir bar sorptive extraction with in-situ derivatization and thermal desorption-gas chromatography-mass spectrometry. Ochiai, N. et al. J. Chromatogr. A. 2003 986,101-110.

Monitoring and fast detection of mycotoxin-producing fungi based on headspace solid-phase microextraction and headspace sorptive extraction of volatile metabolites. Demyttenaere, J. C. R et al. J. Chromatogr. A. 2003 985, 127-135.

Multi-residue screening of pesticides in vegetables, fruits and baby food by stir bar sorptive extraction-thermal desorption-capillary gas chromatography-mass spectrometry. Sandra, P. et al. J. Chromatogr. A. 2003 1000, 299-309.

Stir bar sorptive extraction and large volume injection gas chromatography to determine a group of endocrine disrupters in water samples. Penalver, A. et al. ;J. Chromatogr. A. 2003, 1007, 1-9.

Stir bar sorptive extraction (SBSE) in sample preparation from heterogeneous matrices: determination of pesticide residues in pear pulp at ppb (ng/g) level. Bicchi, C. et al. Eur. Foo Res. Technol. 2003 216, 449-456.

Application of stir bar sorptive extraction to the determination of polycyclic aromatic hydrocarbons in aqueous samples. Kalahgar, B. et al. J. Chromatogr. A. 2002 963 225-230.

Design, Performance and Applicability of a Newly Developed Sample Introduction System for Use with Stir Bar Sorptive Extraction (SBSE) A. Hoffman, B. Kolaghar, C. Heinz, S. Funke, B. Rose Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Quantification of Volatiles in Mammalian Urine by Stir Bar Sorptive Extraction (SBSE) Techniques and Gas Chromatography H.A. Soini, K.E. Bruce, D. Wiesler, M.V. Novotny Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Comprehensive Profiling of Drugs of Abuse in Biological Fluids by SBSE-TD-CGC-MS B. Tienpont, F. David, P. Sandra Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Analysis of Polycyclic Aromatic Hydrocarbon Metabolites in Urine Using in-situ Derivatisation Stir Bar Sorptive Extraction-CGC/MS K. Desmet, P. Kiss, M. DeHertogh, P. Sandra Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Evaluation of the Method of Stir Bar Sorptive Extraction (SBSE) for the Determination of Polycyclic Aromatic Hydrocarbons (PAH) in Water Samples B. Kolahgar, A. Hoffman, A.C. Heiden Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Stir Bar Sorptive Extraction (SBSE) in Sample Preparation from Heterogeneous Matrices: Determination of Pesticide Residues in Pear Pulp at ppb Level C. Bicchi, C. Cordero, C. Iori, P. Rubiolo, P. Sandra Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Headspace Sorptive Extraction (HSSE) B. Tienport, F. David, C. Bicchi, P. Sandra 23rd International Symposium on Capillary Chromatography-Riva del Garada, Italy (2000)

Headspace Sorptive Extraction (HSSE) in the Headspace Analysis of Aromatic and Medicinal Plants Carlo Bicchi, Chiara Cordero, Cristina Iori, Patrizia Rubiolo J. High Resol Chromatogr. 2000, 23, (9) 539-546

Stir Bar Sorptive Extraction-Thermal Desorption-Capillary Gas Chromotography-ICP-Mass Spectrometry for the Determination of Organotin Compounds in Environmental Samples J. Vercauteren, C. Peres, C. Devos, L. Moens, P. Sandra 23rd International Symposium on Capillary Chromatography-Riva del Garda, Italy (2000)

Determination of Contaminants in Wine using Stir Bar Sorptive Extraction (SBSE) F. David, A. Tredoux, E. Baltussen, A. Hoffman, P. Sandra 23rd International Symposium on Capillary Chromatography-Riva del Garda, Italy (2000)

Stir Bar Sorptive Extraction Applied to Lemon Flavored Beverages A.G.J. Tredoux, H.H. Lauer, Th. Heideman, P. Sandra 23rd International Symposium on Capillary Chromatography-Riva del Garda, Italy (2000)

Determination of 2-methlylisoborneol and geosmin in water by gas chromatography-mass spectrometry using stir bar sorptive extraction Sadao Nakamura, Naomi Nakamura, Satoshi Ito J. Sep. Sci 2001, 24,674-677

Stir bar sorptive extraction (SBSE)-enantio MDGC-MS- a rapid method for the enantioselective analysis of chiral flavour compounds in strawberries Mirjam Kreck, Annette Scharrer, Steffi Vilke, Armin Mosandl Eur Food Res Technol (2001) 213:389-394

Determination of trace amounts of off-flavor compounds in drinking water by stir bar sorptive extraction and thermal desorption GC-MS Nabuo Ochiai, Kikuo Sasamoto, Masahiko Takino, Satoru Yamashita, Shigeki Daishma, Arnd Heiden, Andreas Hoffman The Analyst, 2001, 126, 1652-1657

Stir bar sorptive extraction applied to the determination of dicarboximide fungicides in wine Pat Sandra, Bart Tienport, Joeri Vercammen, Andreas Tredoux, Tom Sandra, Frank David Journal of Chromatography A, 928 (2001) 117-126

Analysis of Organochlorine Pesticides in Plant Materials Using Subcritical Water Extraction Combined with SBSE/Thermodesorption-GC/MS Luise Wennrich, Petter Popp Poster, ExTech 2001, Barcelona, Spain

Stir Bar Sorptive Extraction for the Determination of ppq-Level Traces of Organotonin Compounds in Environmental Samples with Thermal Desorption-Capillary Gas Chromatography-ICP Mass Spectrometry Jordy Vercauteren, Christophe Devos, Pat Sandra, Frank Vanhaecke, Luc Moens Analytical Chemistry, Vol. 73, No. 7, April 1, 2001. 1509-1514

Stir bar sorptive extraction-thermal desorption-capillary gas chromatography-mass spectrometry applied to the analysis of polychlorinated biphenyls in human sperm Tom Benjits, Joeri Vercammen, Riet Dams, Hai Pham Tuan, Willy Lambert, Pat Sandra Journal of Chromatography B, 755 (2001) 137-142

Headspace Sorptive Extraction (HSSE), Stir Bar Sorptive Extraction (SBSE), and Solid Phase Microextraction (SPME) Applied to the Analysis of Roasted Arabica Coffee and Coffee Brew Carlo Bicchi, Cristina Iori, Patrizia Rubiolo, Pat Sandra J. Agric. Food Chem. 2002, 50, 499-459

Enantioselective analysis of monoterpene compounds in essential oils by stir bar sorptive extraction (SBSE)-enantio-MDGC-MS Mirjam Kreck, Annette Scharrer, Steffi Bilke, Armin Mosandi Flavour Fragr. J. 2002; 17:32-40

Stir Bar Sorptive Extraction (SBSE), a Novel Extraction Technique for Aqueous Samples: Theory and Principles Erik Baltussen, Pat Sandra, Frank David, Carel Cramers J. Microcolumn Separations, 11(10) 737-747 (1999)

Membrane-Enclosed Sorptive Coating. An Integrative Passive Sampler for Monitoring Organic Contaminants in Water Branislav Vrana, Peter Popp, Albrecht Paschke, Gerrit  Analytical Chemistry, Vol. 73, No. 21, November 1, 2001. 5191-5200

Flavor, Fragrance and Odor Analysis Ray Marsili, Ed. Marcel Dekker (2001)

Influence on Recovery of Stir Bar Sorptive Extraction (SBSE) of Water/PDMS Phase Ratio, Volume of PDMS Coated onto the Stir Bar and Sampling Temperature C. Bicchi, C. Cordero, C. Iori, P. Rubiolo, P. Sandra Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Study on Highly Sensitive Analysis of Flavor Compounds in Beverage by Gas Chromatography/Mass Spectrometry with Static and Dynamic Headspace Technique Nobuo Ochiai, Norihiro Sakui, Shigeki Daishima, Daniel B. Cardin 22nd International Symposium on Capillary Chromatography-Gifu, Japan (1999)

Comparison of headspace sampling and stir bar sorptive extraction in the detection of whiskey adulteration with a mass-spectrometry based chemical sensor V.R. Kinton, E.A. Pfannkoch Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Monitoring and Fast Detection of Mycotoxin Producing Fungi Based on Headspace Solid Phase Microextraction of the Volatile Metabolites J.C.R. Demyttenaere, R.M. Morira, P. Sandra, M. Schelfaut Symposium on Capillary Chromatography and Electrophoresis-Riva del Garda, Italy (2002)

Application of stir bar sorptive extraction in combination with column liquid chromatography for the determination of polycyclic aromatic hydrocarbons in water samples Peter Popp, Coretta Bauer, Luise Wennrich Analytica Chimica Acta 436 (2001) 1-9

High Capacity Headspace Sorptive Extraction B. Tienpont, F. David, D. Bicchi, P. Sandra J. Microcolumn Separations, 12(11) 577-584 (2000)

The Determination of Benzoic Acid in Lemon Flavored Beverages by Stir Bar Sorptive Extraction-CGC-MS Andreas G.J. Tredoux, Henk H. Lauer, Theo Heideman, Pat Sandra J. High Resol. Chromatogr. 2000, 23, (11) 644-646

Stir Bar Sorptive Extraction (SBSE): A Novel Technique for the Determination of Organic Micropollutants in Water Samples Dr. Pat Sandra Water/Waste Water, March/April- Volume 11, Issue 2