2
Table of Contents
Introduction................................. 2
Basic Principles ofHeadspace
Analysis ........................................ 3
• Partition Coefficient
• PhaseRatio
•CombiningK and
β
•Derivatization/Reaction
Headspace
•Headspace Sample Size
Instrumentation .......................... 6
•Gas-Tight Syringe Injection
•Balanced-Pressure System
• Pressure-Loop System
SystemOptimization
(Troubleshooting) ........................ 8
• Sample Preparation
• SampleVial
• SampleVial Heater andMixer
• Sampling
• Transfer Line
• Injection Port Interface
HeadspaceApplications ........... 11
•BloodAlcoholAnalysis
•USP<467>
• European Pharmacopoeia Tests
RecommendedHeadspaceAnalysis
Products ..................................... 15
•Capillary Columns
•Guard Columns
• Press-Tight
®
Connectors
•Analytical ReferenceMaterials
•GCAccessories
tatic headspace gas chromatography (GC) is a technique used for the concentra-
tion and analysis of volatile organic compounds. This technique is relatively
S
Time andmoney are two of themany reasonswhy an analyst
woulduse static headspace analysis. Other reasonsmay include
ease of operation and the ability to assay a variety of sample
matrices.
simple and can provide sensitivity similar to dynamic purge and trap analysis. The
popularity of this technique has grown and has gainedworldwide acceptance for
analyses of alcohols in blood and residual solvents in pharmaceutical products.
Other common applications include industrial analyses ofmonomers in polymers
and plastic, flavor compounds in beverages and food products, and fragrances in
perfumes and cosmetics.
Samplematrices like blood, plastic, and cosmetics contain highmolecular weight,
non-volatilematerial that can remain in theGC system and result in poor analytical
performance.Many laboratory analysts use extensive sample preparation techniques
to extract and concentrate the compounds of interest from this unwanted non-
volatilematerial. These extraction and concentration techniques can become time
consuming and costly. Static headspace analysis avoids this time and cost by directly
sampling the volatile headspace from the container inwhich the sample is placed.
Because of the diversities in the industry and related products, this guide attempts to
cover only the basic principles of static headspace and demonstrate how to apply
them to achieve optimum chromatographic results.With an understanding of these
principles, various instrumentationwill then be reviewed to help build upon this
knowledge and identify the benefits and potential problems associatedwith each
mode of sample transfer. Information from the
Basic Principles
and
Instrumentation
sections of this guide can then be brought together and applied to the conditions and
methodology of common analyses. Likemost applications, a variety of problems
may arise inwhich the
SystemOptimization
sectionwill help to identify these
problems and offer techniques to help resolve them.
✶
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