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2004 vol. 3

Redesigned Rt-QPLOT

™

GSC Columns

For Improved Inertness, Reproducibility, and Column Lifetime

by Barry Burger, Petroleum Chemist

•Sharp peaks and excellent resolution for alcohols.

• Effective particle bonding eliminates the need for particle traps.

•Stable to 310ºC, for effective reconditioning.

The most common mode of gas chromatography,

gas-liquid chromatography (GLC), has limitations

in analyses of gases and highly volatile analytes.

Subambient temperatures often are required in

these applications, and cryogenic cooling sys-

tems are costly and inconvenient. In gas-solid

chromatography (GSC) these small molecules

are absorbed into the pore structure of the

packing material, which provides strong reten-

tion and unique selectivity. By this approach, dif-

ficult-to-separate gaseous or highly volatile ana-

lytes can be separated at above ambient tem-

peratures.

Just as capillary columns offer advantages over

packed GLC columns, porous layer open tubular

columns—PLOT columns—offer significant

advantages over packed GSC columns. PLOT

columns provide faster and more sensitive

analyses. Their open design gives PLOT columns

greater permeability, and their narrow diameter

ensures sharper peaks. The open construction

affords a smaller pressure drop per unit length,

so longer columns can be used. This means

much higher column efficiency and, therefore,

superior resolution.

Rt-QPLOT

™

, Rt-SPLOT

™

, and Rt-UPLOT

™

columns

are porous polymer based PLOT columns that

incorporate polar functional groups in a

styrene/divinylbenzene matrix. The least polar of

these, the nonpolar Rt-QPLOT

™

columns, are

made with divinylbenzene. Rt-QPLOT

™

columns

are well suited to a wide variety of ambient-

temperature analyses, including hydrocarbon

mixtures and solvents. An Rt-QPLOT

™

column is

an excellent choice for analyzing alcohols

(Figure 1) or polar solvents (Figure 2).

Additional separations on Rt-QPLOT

™

columns

are in the GC Applications section of our catalog

(Permanent Gases, Hydrocarbon Gases, and

Solvents sub-sections), and on our website.

An Rt-QPLOT

™

column requires no particle trap

and exhibits minimum bleed (<20pA at 310°C).

Unlike alumina or molecular sieve PLOT

columns, porous polymer PLOT columns are

unaffected by moisture, and thus are particular-

ly useful for applications in which water is likely

to be part of the sample.

We think you will find the performance, column

lifetime, and reproducibility of our PLOT columns

superior to any other PLOT columns available.

Why Use RESTEK PLOT Columns?

1. Uniform, highly consistent porous materials,

for the most efficient and consistent analyses.

2. Advanced manufacturing technology and

demanding quality assurance ensure highly

reproducible quality.

3. Choice of alumina, three porous polymers,

and molecular sieve—you can perfectly

match a column to your application.

4. Highly efficient particle bonding - no loose

particles to enter your system, no need for

particle traps.

Rt-QPLOT

™

PLOT Columns (fused silica)

(divinylbenzene)

df (µm)

temp. limits

15-Meter

30-Meter

0.32mm

to 310°C

19717

$365

19718

$500

0.53mm

to 310°C

19715

$390

19716

$540

min

30m, 0.32mm ID, 10µm Rt-QPLOT

™

(cat.# 19718)

1.0µL split injection of alcohol mixture

Conc.:

1% of each compound in water

Oven program:

100°C to 240°C @ 5°C/min.

(hold 10 min.)

Injector:

split @ 250°C

Carrier gas:

helium (constant pressure mode)

Head pressure:

18.0psi

Column flow rate: 1.1cc/min. @ 100°C

Linear velocity:

31cm/sec. @ 100°C

Split ratio:

70:1

Detector:

FID @ 270°C

Make-up gas flow: 45cc/min.

Inlet liner:

4mm single gooseneck (cat.# 20798)

1. methanol

2. ethanol

3. 2-propanol

4. 1-propanol

tert

-butanol

6. 2-butanol

7. isobutyl alcohol

8. 1-butanol

9. 2-methyl-2-butanol

10. 3-methyl-1-butanol

11. 4-methyl-2-pentanol

GC_CH00495

Figure 1

Sharp peaks and excellent resolution of alcohols on an Rt-QPLOT™ column.

Figure 2

Fast, baseline resolution of polar and nonpolar

solvents on an Rt-QPLOT™ column.

30m, 0.32mm ID Rt-QPLOT

™

PLOT (cat.# 19718)

20µL split injection. 50ppm (w/v) each in helium with a

Cyclosplitter

liner (cat.# 20755)

Oven temp.:

150°C

Inj./det. temp.:

200°C

Carrier gas:

hydrogen

Det.:

FID

Split ratio:

20/1

1. methane

2. methanol

3. ethanol

4. acetone

-pentane

6. ethyl acetate

-hexane

1 2 3 4 5 6 7 8 9 10 11 min.

GC_PC00181

For performance and ordering information for

Rt-SPLOT

™

and Rt-UPLOT

™

columns, refer to our

catalog or website.