Robust GC Analysis of Volatile Amines on the Rtx-Volatile Amine Column

• Highly robust phase withstands harsh matrices for longer column lifetime.
• Stable column chemistry produces excellent reproducibility.
• QC tested with a specially designed test mix to ensure performance.

Volatile amines are used as gas-scrubbing agents to remove hydrogen sulfide from refinery gas streams, as well as for removing carbon dioxide during the production of ammonia. While accurate data on volatile amine content is vital for optimizing the manufacture of compounds from many different classes, GC analysis of volatile amines can be quite challenging due to their basic nature and high polarity. Because of these characteristics, volatile amines will interact with active sites in the analytical column and along the sample pathway, resulting in broad, tailing peaks that are difficult to accurately integrate.

In order to ensure good chromatography for the GC analysis of volatile amines, capillary columns must be highly inert and offer good retention and efficiency. In addition, the GC column phase must be able to withstand tough matrices because volatile amines are often analyzed in the presence of water, alcohol, or ammonia. Base-modified polyethylene glycol columns are sometimes used, but they suffer from relatively poor stability and a loss of efficiency below 60 °C. Siloxane columns can also be used, as long as relatively pure samples are being analyzed. However, most siloxane columns break down in the presence of harsh matrices, such as water, resulting in short column lifetimes and poor reproducibility. Restek’s Rtx-Volatile Amine column is a better alternative that offers greater stability and improved chromatographic performance for the GC analysis of volatile amines.

The Rtx-Volatile Amine column was designed specifically for analyzing volatile amines in difficult matrices. As shown here, the stable bonded phase yields a column that is not only retentive and highly selective for basic compounds, but is also very robust and able to withstand repeated water injections. Every Rtx-Volatile Amine column is held to stringent quality specifications and QC tested to ensure consistent performance, making Rtx-Volatile Amine columns the best choice for GC analysis of volatile amines.

	Peaks	tR (min)
1.	Pyridine	4.95
2.	1,2-Butanediol	5.76
3.	Nonane	7.62
4.	Diethylenetriamine	11.07
5.	Diethanolamine	11.90
6.	2-Nonanol	14.80
7.	2,6-Dimethylamine	20.45
8.	Dodecane*	22.25

Column	Rtx-Volatile Amine, 60 m, 0.32 mm ID (cat.# 18078)
Standard/Sample	Volatile amine column test mix (cat.# 35008)
Diluent:	Methanol:dichloromethane (50:50)
Conc.:	900-1,800 µg/mL snap and shoot
Injection
Inj. Vol.:	1 µL split (split ratio 17.8:1)
Liner:	Premium 4 mm single taper w/wool (cat.# 23303)
Inj. Temp.:	250 °C
Split Vent Flow Rate:	60 mL/min.
Oven
Oven Temp.:	160 °C (hold 21 min) to 290 °C at 40 °C/min (hold 10 min)
Carrier Gas	He, constant flow
Flow Rate:	3.4 mL/min
Linear Velocity:	44 cm/sec @ 160 °C

Detector	FID @ 300 °C
Make-up Gas Flow Rate:	30 mL/min
Make-up Gas Type:	N2
Data Rate:	50 Hz
Instrument	Agilent/HP6890 GC
Notes	*Peak responses are normalized on dodecane.

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