Gas-phase capillary column-comparison of special column for amine analysis and conventional gas-phase analysis column

Welch WM-5Amine is a special column for amine analysis. Its surface is deactivated by alkali. When analyzing amines, it can effectively reduce the occurrence of peak tailing. In this paper, triethylamine will be used as an example. Methods The Welch special column for amine analysis WM-5Amine (30m×0.32mm, 1.0μm) was compared with the Welch conventional gas phase analysis column WM-InoWAX (30m×0.32mm, 1.0μm).

Gas chromatography conditions

Method 1:

Column flow rate: 1.0mL/min

Column temperature: the initial temperature is 40 °C, and the temperature is increased to 140 °C at 8 °C/min and maintained for 10 min

Inlet: 275℃

Detector: FID 250℃

Carrier gas: nitrogen

Injection volume: 1 μL

Split ratio: 50-1

Sample configuration

Using N,N-dimethylformamide as a solvent, triethylamine was prepared at 0.0306 mg/mL and 10.2 mg/mL, respectively.

Chromatogram

Welch WM-5Amine (30m×0.32mm, 1.0μm) (P/N: 07956-32003)

1.Triethylamine solution (10.2mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	5.605	10075.88	3886.28	166412	n.a.	1.033

2.Triethylamine solution (0.0306mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	5.607	307.15	117.84	105079	n.a.	1.082

Welch WM-INOWAX (30m×0.32mm, 1.0μm) (P/N: 03909-32003)

1.Triethylamine solution (10.2mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	3.486	8560.44	2591.47	26744	n.a.	1.186

2.Triethylamine solution (0.0306mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	3.492	285.57	81.93	25133	n.a.	1.252

Method 2:

Column flow rate: 1.0mL/min

Column temperature: the initial temperature was kept at 65 °C for 5 min, and then increased to 220 °C at 10 °C/min and maintained for 15 min

Inlet: 200℃

Detector: FID 250℃

Carrier gas: nitrogen

Injection volume: 1 μL

Split ratio: 1-1

Sample configuration

Using N,N-dimethylformamide as a solvent, triethylamine was prepared at 0.0012 mg/mL and 0.06 mg/mL, respectively.

Chromatogram

Welch WM-5Amine (30m×0.32mm, 1.0μm) (P/N: 07956-32003)

1.Triethylamine solution (0.06mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	5.423	5653.1	1078.11	25748	n.a.	1.323

2.Triethylamine solution (0.0012mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	5.432	110.51	23.51	28560	n.a.	1.203

Welch WM-INOWAX (30m×0.32mm, 1.0μm) (P/N: 03909-32003)

1.Triethylamine solution (0.06mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	3.233	7001.11	1193.13	7711	n.a.	1.565

2.Triethylamine solution (0.0012mg/mL)

Name	Retention time	Area	Height	Number of plates	Degree of separation	Tailing factor
Triethylamine	3.227	128.27	21.43	7609	n.a.	1.603

In conclusion

Using Welch WM-5Amine (30m×0.32mm, 1.0μm) (P/N: 07956-32003) chromatographic column to determine triethylamine under the above two chromatographic conditions, both peak shape and theoretical plate number are better than Column Welch WM-INOWAX.