Application Notes: GC-MS

This application note presents thermal extraction of phthalates in accordance with IEC Method 62321-8 using a 6150 Pyroprobe.

Solvent-reduced determination of 100 contaminants from low double-digit to low triple-digit pg/L in 100 mL surface water samples, meeting the requirements of the EU-WFD based on SBSE-TD-GC-MS/MS

Quantifies affinity, stoichiometry of biomolecular assemblies, helping understand the mechanism of interaction and develop therapeutics that target and modulate them.

Quantifies affinity, stoichiometry of biomolecular assemblies, helping understand the mechanism of interaction and develop therapeutics that target and modulate them.

Most recently formulated pesticides are smaller in molecular weight and designed to break down rapidly in the environment.

SPME-GC–MS with on-column injection can be successfully employed for flavour profiling of food samples. The on-column injector of the GC-2010 can be used for SPME without any modifications, only an external ring adapter was used to facilitate the injection. The data can be compared with sensorial data of food.

The composition and analysis of fragrance components in home and personal care (HPC) products is very complex and unquestionably time consuming.

The QuEChERS method for pesticide analysis was first introduced by USDA scientists in 2003. The EN method 15662:2007 is a European variation to the QuEChERS method. The method uses acetonitrile extraction, followed by the salting out of water from the sample using anhydrous magnesium sulphate (MgSO4, NaCl and buffering citrate salts to induce liquid–liquid partitioning.

Polybrominated diphenyl ethers (PBDEs) are bioaccumulativetoxic compounds that are used as flame retardants. They have high boiling points and low thermal stability which makes analysis by GC–MS challenging. Additional bromines increase the thermal instability. A method was developed to analyze for polybrominated biphenyls using a large volume injection, short analytical column, and high mass tuning algorithm on the Thermo Scientific DSQ II with detection by EI Single Ion Monitoring (SIM).

Illegal drug use worldwide is at an all time high. Forensic laboratories are seeing increased sample loads creating an immediate need for fast and accurate analysis to positively identify confiscated materials in criminal investigations. This application highlights the value of gas chromatography with time-of-flight mass spectrometry (GC-TOFMS) for drug testing in forensic laboratories. A method was developed to successfully identify twenty drugs of abuse in 4.5 min. This GC-TOFMS method shows good chromatographic peak shape for even the most challenging drug analytes; even the peak shapes for amphetamine and methamphetamine were exceptional considering they were analyzed underivatized. The total ion chromatogram (TIC) for the twenty drug analytes is shown in Figure 1.

GC–MS method is presented for the quantitative determination and confirmation of melamine residues in milk products. The milk sample was cleaned up using Agilent's SampliQ SCX SPE cartridges before derivatization. The derived extracts were analysed by GC–MS with EI in synchronous SIM/scan mode on a Agilent J&W DB-5ms Ultra Inert column.

Polybrominated diphenyl ethers (PBDE) are persistent environmental contaminants that are being extensively studied by environmental researchers worldwide. Their potential for toxicological impacts on humans and wildlife has made them a focal point of regulatory agencies. Their widespread use as flame retardants in electronics, household furniture, and many other building materials has lead to a need for analysis of many different sample matrices, including very complex environmental samples.

The recent establishment of a 1 μg/g safety threshold for melamine in infant foods has led to an immediate need for more sensitive methods. Here we established GC–MS conditions for highly reproducible analyses and evaluated the effectiveness of both solvent-based and matrix-matched standards. Using this method, melamine and cyanuric acid were reliably detected at and below 1 μg/g in infant formula.

Melamine is an industrial chemical with a high nitrogen content that can cause kidney stones and lead to renal failure. In some instances, melamine has been added to baby formula and dairy products as a substitute for protein. This paper presents an efficient and definitive gas chromatography–mass spectrometry (GC–MS) method to identify melamine and related compounds based on the released US Food and Drug Administration (FDA) method.

Thermo

Purge and trap concentration (P&T) along with gas chromatographic analysis is a widely used method for the detection of volatile organic compounds (VOCs). This methodology was developed to achieve the high sensitivity necessary to determine VOCs in drinking water according to EPA Method 524.2. Research is now complete and the EPA currently proposes a revision to this method that may include a revised list of analytes including iodinated trihalomethanes, fuel oxygenates, and Contaminant Candidate List 3. This new method will be 524.3 and may include new parameter optimizations not previously permitted in 524.2 as well as the ability to use selective ion monitoring (SIM) analysis for troublesome compounds.

The CUSTODIONâ„¢ solid phase microextraction (SPME) syringe was used to rapidly sample and concentrate volatile organic compounds (VOCs) from water in 5 s. The VOCs were analyzed quickly and reliably in approximately 70 s using the GUARDIONâ„¢ -7 portable capillary gas chromatograph toroidal ion trap mass spectrometer (GC-TMS).

Melamine is an industrial chemical with a high nitrogen content that can cause kidney stones and lead to renal failure. In some instances, melamine has been added to baby formula and dairy products as a substitute for protein. This paper presents an efficient and definitive gas chromatography–mass spectrometry (GC–MS) method to identify melamine and related compounds based on the released US Food and Drug Administration (FDA) method.

This application details a fast, reliable and highly selective trace-level screening method for the quantification of polychlorinated biphenyls (PCBs) in environmental, food and biological samples, using gas chromatography and a triple stage quadrupole mass spectrometer. The analytical strategy is analogous to the well-established US Environmental Protection Agency (USEPA) Method 1668A.

The CUSTODION™ SPME Syringes are a series of novel solid phase micro extraction syringes that incorporate Supelco Analytical's® (Bellefonte, Pennsylvania) SPME fiber technology. The SPME syringes are fabricated with injection-molded components and the device resembles a ball-point pen. The Supelco Analytical® SPME fiber assembly is housed inside the syringe.

Screening for pesticide content is a common analysis that is done in laboratories where many samples need to be analyzed over a short period of time. The desire for a high-speed analysis is due to the need for a fast result from a potentially large volume of samples. A fast analysis is typically achieved through the use of high carrier gas flow rates in combination with temperature programming. A fast detector is needed in order to fully characterize the narrow chromatographic peaks generated from these experiments. TOFMS is ideal for detecting these narrow peaks because of its fast acquisition rate over a full mass range at all times during the experiment. In addition, TOFMS provides for non-skewed mass spectra making peak deconvolution possible.

Use of a modified QuEChERS sample preparation procedure was fully evaluated for identification and quantitation of pesticides in lettuce using gas chromatography and ion trap mass spectrometry. Final results compared favorably to the reporting and detection limits offered by several worldwide agencies, demonstrating a robust and reliable solution for analyzing pesticide residues in lettuce.

The second unregulated contaminant monitoring regulation (UCMR2) program was developed to monitor US drinking water sources for currently unregulated compounds. EPA Method 527 is categorized under List 1; Assessment Monitoring in the UCMR2 program. EPA Method 527 focuses on a wide range of semi volatile organic contaminants, including pesticides that were deferred during the first UCMR, flame retardants, and pyrethroid pesticides. This application for EPA Method 527 employs SPE with analysis by gas chromatography–mass spectrometry (GC–MS).

Capillary flow technology (CFT) devices are microfluidic components that extend capillary GC capabilities through simple and robust connections between pressure/flow modules and columns. One of the most powerful and simple is the CFT Tee. This is especially useful in GC–MS analysis providing (1) rapid column and inlet maintenance without MSD venting and (2) the capability of rapidly removing late eluting interferences from the column by forcing their retreat into the injection port through "backflushing". Removing these interferences improves column and detector longevity and analytical integrity. Backflushing is very valuable for trace GC–MS analysis in samples from complex matrices like soil, foods or tissues. The CFT Tee uses pressure-pulsed injections and constant flow mode with minimal loss in the MS signal. This approach will be useful to all GC–MS users who want to improve their instrument uptime.

A new APCI/APLI source enables a high resolution TOF-MS to be coupled on LC and GC, thus increasing flexibility and performance of TOF-MS in combination with GC.

H-SRM provides excellent selectivity for accurate identification and quantification of pesticides in matrix, demonstrating high productivity for effective control at international maximum residue levels (MRLs).

Phthalates are added to plastics to increase flexibility. Recently, concerns have been raised over the effect of phthalate exposure from plastic materials on human health.