Fast Analysis of Malt Whisky by GC–MS Using an Ultra High Performance VF-WAXms Column from Varian, Inc.

John Oosdijk¹ and Graham Farrell,²

¹ Varian, Inc., Middelburg, The Netherlands,

² Polymer Laboratories, now a part of Varian, Inc., Church Stretton, Shropshire, UK.

The flavours of malt whisky result from a complex blend of long chain esters and alcohols, derived from the distillation products and the composition of the wooden barrels in which the finished product is aged. As shown below, the new VF-WAXms column from Varian, Inc. is ideal for analysing whisky, especially when trace analysis is needed. The column's ultra-low bleed increases sensitivity, extends column life and improves accuracy, even at higher temperatures. In addition, VF-WAXms columns are suitable for use with MS detectors, as the ultra low bleed eliminates interferences and permits more sensitive detection.

Figure 1

VF-WAXms 0.15 mm i.d. columns have the added advantage of combining high resolution analysis with much faster run times, thus increasing productivity without the need to invest in new hardware. They can be used on all GC and detector combinations unlike other smaller i.d. types (e.g., 0.1 mm) that might require a hardware change. The 0.15 mm columns also have a greater loadability than 0.1 mm i.d. versions. VF-WAXms 0.15 mm i.d. columns, therefore, provide a perfect combination of productivity, high resolution, loadability and ease-of-use.

The value of the columns is clear in the analysis of malt whisky, where reduced column bleed in the 210–260 °C temperature range enables a more accurate detection and quantification of impurities in the whisky that elute close to the maximum temperature of the column. The presence of capric acid and other minor impurities, which elute at these higher temperatures, is revealed at lower concentration levels and with improved accuracy and analysis speed.

Sample: Single malt whisky

Column: VF-WAXms, 15 m × 0.15 mm × 0.15 μm

Technique: GC–MS (CP-3800 GC with 320MS)

Oven: 35 °C 3 min, 25 °C/min; 260 °C 10 min

Carrier gas: Helium, 2 mL/min

Injector: Split 1:20, T = 220 °C

Sample size: 1 μL

Detector: MS (EI), mz 21–350

Varian, Inc.

Postbus 8005, 4330 EA Middelburg, The Netherlands.

tel. +31 118 671 5000 fax +31 118 671 502

Website: www.varianinc.com