Instrumentation for Gas Chromatography - Forensic Applications of Gas Chromatography - page 18

Table 2.1 General Guidance on Capillary GC Stationary Phase Selection

Compound
Polarity

General Characteristics
of Compound

Typical Example
Stationary Phases Example Compounds

Nonpolar C and H only; C-C bonds Alkanes DB-1

Polar Mainly C and H atoms

but also O, N and S

Alcohols, amines,
carboxylic acids, ketones

DB-35

Polarisable C and H only; C = C or

C≡C bonds

Alkenes, alkynes,
aromatic hydrocarbons

DB-FFAP

Table 2.2 Example Capillary GC
Stationary Phases Used in Forensic Analysis

Forensic Application Typical Stationary Phases

Accelerants DB-1 or DB-5MS

Blood alcohol DB-1

Barbiturates DB-5MS

Cannabinoids (TMS a ) DB-5MS

Cocaine (TMS a ) DB-5MS

Inhalants DB-5MS

LSD (TMS a ) DB-5MS

Opiates (TMS a ) DB-5MS

Steroids DB-5MS

Tryptamines DB-5MS

a TMS = trimethylsiloxane derivative.

is to select a DB-1 or DB-5 * equivalent column. GC column manufactur-
ers produce catalogues that describe the performance of their different
columns with respect to different applications. By comparison of the chro-
matogram produced by a specific column under specified operating condi-
tions, it is possible to identify a satisfactory column for a specific application.
Manufacturers generally catalogue chromatograms based on the following
application areas: environmental; chemical; food, flavours and fragrances;
forensic; and fuels and petrochemicals. Some example capillary GC columns
as used in forensic applications are shown in Table 2.2.

* The different manufacturers of GC columns use specific alpha and numeric system
designations to identify their brand of column; fortunately, they often retain the same
numeric values to allow cross reference from one manufacturer to another. For example,
a DB-5 (from J&W) is similar to an HP-5 (from Agilent) as well as an RTX-5 (from Restek),
a BP-5 (from SGE), and an SPB-5 (from Supelco); other examples are shown in Table 2.3.