Microbial VOC's in Air using the Entech 7500/8000 Robotic Heated Canister GC/MS Inlet
A new canister based method is presented that allows the analysis of Microbial Volatile Organic Compounds (MVOCs) in air at the Sub-Part-Per-Billion levels. This technique is performed using whole air sampling into Silonite coated MiniCans and analyzed with the Entech Instrument's Model 7500 Robotic Canister/Headspace Autosampler and 8000 inlet system using a gas chromatograph/mass spectrometer. Recovery of heavier MVOCs, including Geosmin, is accomplished by heating the canisters to 90 deg. C prior to sample extraction. A calibration table showing linearity down to 0.03ng injected is presented.
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Comparison of Silonite Coated Injection Port Liners to Glass Liners
in the Analysis of Semi-Volatile Organics by Gas Chromatography
The injection port liner is the first surface a sample makes contact with upon injection into a gas chromatograph. This region must be at a temperature between 250 and 300 C to effectively vaporize the sample when analyzing for semi-volatile organic compounds. At elevated temperatures certain compounds can exhibit breakdown if there is any activity in the injection port and primarily in the injection port liner. The material best suited for this purpose is glass, but even glass can be very active and has to have surface deactivation.
Our presentation demonstrates breakdown that occurs with glass versus glass that has been specially deactivated by Silonite coating. Silonite coating is a process that bonds fused silica to the surface of glass or stainless steel, creating a very inert surface. Our data shows Silonite coated injection port liners provide the lowest breakdown attainable while maximizing the sensitivity
for high molecular weight compounds.
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Semi-Volatile Organic Chemicals in Ambient Air by Heated Silonite Canister/8000 GC Inlet/GCMS Analysis
A new canister based method is presented that allows the analysis of Semi-Volatile compounds in air at the Sub-Part-Per Billion levels. This technique is performed using whole air sampling into Silonite coated MiniCans and analyzed with the Entech Instruments Model 8000 inlet system using a gas chromatograph/mass spectrometer. Laboratory efficiency is greatly improved by eliminating the manually intensive process of solvent extraction currently used by semi-volatile air monitoring methods. The sampling process can be used for the monitoring of volatile chemicals as well, with only a change in the preconcentration method and GC column used.
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Large Volume Static Headspace (LVSH) A New High Sensitivity GC Headspace Technique
In this presentation, Dan Cardin, President of Entech Instruments introduces and describes how Large Volume Static Headspace (LVSH) sample introduction into a GCMS is performed. He examines the use of LVSH in the analysis of samples benefiting from trace static headspace
analysis (Food aromas, Fragrances in flowers, packaging contaminants) and Compares LVSH to other Headspace Techniques Relative to Sensitivity, Statistical Accuracy, Carryover, and Matrix Interference.
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