Fruit and vegetable extracts that are produced following the well established QuEChERS method [1,2] typically contain a significant amount of involatile matrix material. After several injections of such extracts into the GC, sufficient matrix residue will be present in the GC inlet liner to lower or sometimes even increase the response of certain pesticide compounds…
A method for the determination of trace amounts of off-flavor compounds such as 2-methyl isoborneol (MIB), geosmin and 2,4,6-trichloroanisole (TCA) in drinking water is described based on dynamic headspace coupled to selectable onedimensional or two-dimensional gas chromatography – mass spectrometry with simultaneous olfactory detection (DHS1D/2D GC-O/MS). Automated DHS using a Tenax TA packed tube as…
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…
One of the most important aspects of reducing pesticide exposure is monitoring of pesticide residues in foods. A number of analytical methods have been developed, many of them based on traditional liquid-liquid extraction in combination with GC-MS or LC-MS. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation methods have been developed to…
The extraction of Afl atoxin B1 residues from contaminated corn samples using disposable pipette extraction (DPX) is described. DPX is a solid-phase extraction (SPE) technique that is based on loosely contained sorbent inside a pipette tip fitted with a screen. This device provides faster extraction because only minimal conditioning steps are needed. A weak anion…
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 desorptiongas chromatography-mass spectrometry (TD-GC-MS). Direct Large Volume Injection (LVI) -GC-MS was used as reference method. Optimized methods for…
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 Sampler (MPS), the second involves thermal desorption of the material in question in the GERSTEL Thermal Desorption Unit (TDU). Both…
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…
Identifi cation of important trace components in complex samples like fragrances, natural products, polymers or food products can be challenging. Achieving the mass on column and resolution necessary to locate peaks and identify trace components using a single column chromatographic separation can be difficult, if not impossible. A selectable 1D/2D GC-MS configuration based on Agilent®…
A procedure is presented for quantification of Ethyl Carbamate at low μg/L levels in distilled spirits. A 100 μL large volume injection was used followed by orthogonal 2-dimensional GC-MS with heartcutting. The direct large volume injection ensured sufficient availability of analyte without an initial sample preparation step, and the 2D step allowed clean elution of…
Acrylamide is thought to be produced during the roasting process associated with coffee production. Acrylamide has been labeled as a probable human carcinogen. Due to the use of roasted coffee beans in making coffee and the high consumption of coffee world-wide, brewed coffee could be a source of daily exposure to acrylamide. Acrylamide determination has…
Modern capillary GC injection generally uses the universal dual mode split/splitless injection port or inlet in which the pneumatic mode is selected at the outset. The inlet is maintained at a sufficiently high set temperature to allow instant vaporization of the sample after deposition in the inlet liner (usually 4mm i.d.) Of course this explosive…
Determination of total fat, saturated fat, monounsaturated fat and trans fat content in food samples is necessary for complying with applicable food labeling requirements. A typical procedure for saponification of the sample involves refluxing with sodium methoxide in methanol, followed by a second reflux with boron trifluoride in order to esterify the free fatty acids.…
QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation methods have been developed to help monitor pesticides in a range of food samples. These methods require many manual steps, such as shaking, centrifugation, and dispersive SPE, making it a quite labor-intensive process. There is a need for automating the dispersive SPE technique to clean…
Glyphosate and glufosinate are widely used herbicides and, thus, there is an interest in the reliable and sensitive determination of glyphosate in water and food. These pesticides are difficult to extract and analyze because of their high polarity. In this report, we describe an automated workflow for the FMOC-derivatization, sample cleanup, and LC/MS/MS analysis using…
In this report, we describe a completely automated sample preparation workflow for the extraction and screening of multi-mycotoxin residues in different food matrices (corn, wheat) by LC/MS/MS. The extraction and cleanup was performed using a GERSTEL MultiPurpose Sampler (MPS XL) followed by LC/MS/MS determination using an AB SCIEX QTRAP® 4500. The automated sample preparation workflow…
This application note describes the direct thermal desorption of desirable and undesirable aroma compounds from edible oils. The oil sample is placed in a microvial from where it is directly thermally desorbed using a GERSTEL Thermal Desorption Unit (TDU). Volatile compounds are transferred to the GC/MS system while leaving the non-volatile oil matrix behind in…
One of the most important aspects of reducing pesticide exposure is monitoring of pesticide residues in foods. A number of analytical methods have been developed, many of them based on traditional liquid-liquid extraction in combination with GC-MS or LC-MS. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation methods have been developed to…