This technique is used to determine the mass concentration of caffeine and acesulfame K, as well as ascorbic acid, sorbic acid, benzoic acid, saccharin, and their respective salts in beverages. The technique applies to all kinds of alcoholic and non-alcoholic beverages, including energy and sports drinks, juices, wines, beers and beer products, vodka, brandy and spirits, and liquors.
Measurement Method
The ionic and neutral forms of analyzed components can be separated using micellar electrokinetic chromatography (MEKC). The components are detected by measuring their intrinsic absorption at a wavelength of 254 nm.
Measurement Range
The table below presents the analyzed components’ measurement range.
| Compound |
CSFA code |
E number |
Determined form |
Measurement range*, mg/L |
| Caffeine |
- |
- |
Caffeine |
10-1000 |
Sorbic acid
Sodium sorbate
Potassium sorbate
Calcium sorbate |
INS 200
INS 201
INS 202
INS 203 |
E 200
E 201
E 202
E 203 |
Sorbic acid |
Benzoic acid
Sodium benzoate
Potassium benzoate
Calcium benzoate |
INS 210
INS 211
INS 212
INS 213 |
E 210
E 211
E 212
E 213 |
Benzoic acid |
Ascorbic acid
Sodium ascorbate
Calcium ascorbate
Potassium ascorbate |
INS 300
INS 301
INS 302
INS 303 |
E 300
E 301
E 302
E 303 |
Ascorbic acid |
| Acesulfame K |
INS 950 |
E 950 |
Acesulfame K |
Saccharin
Calcium saccharin
Potassium saccharin
Sodium saccharin |
INS 954(i)
INS 954(ii)
INS 954(iii)
INS 954(iv) |
E 954(i)
E 954(ii)
E 954(iii)
E 954(iv) |
Sodium saccharin |
* For every mentioned form of the food additive.
Certain food additives (such as E 200- E 203, E 210 – E 213, E 300 – E 303, and E 954) cannot be determined using the present technique. The analysis will not be adversely affected by the presence of other sweeteners (such as cyclamate or aspartame), vanillin, B vitamins, or synthetic food dyes, if their concentrations are within the typical ranges for this type of beverage.
Equipment and Reagents
When undertaking measurements, the CAPEL capillary electrophoresis system is used. A personal computer which runs under the Windows® operating system with the dedicated ELFORUN software package also installed is used for the acquisition of data, collection, processing, and output.
Example of a Real Analysis
| . |
. |
| BGE: |
borate, with SDS |
| Capillary: |
Leff/ Ltot 50/60 cm, ID 75 µm |
| Injection: |
150 mbar x sec |
| Voltage: |
+ 25 kV |
| Temperature: |
20 °C |
| Detection: |
254 nm |
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Sample: test mixture (30 mg/L of each compound)
1 – Caffeine
2 – Ascorbic acid
3 – Sorbic acid
4 – Benzoic acid
5 – Sodium saccharin
6 – Acesulfame K
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Sample: soft drink, undiluted
Measurement Results
1 – Caffeine (90 mg/L)
2 – Benzoic acid (120 mg/L)
3 – Acesulfame K (130 mg/L)
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Sample: energy drink, fivefold diluted
Measurement Results
1 – Caffeine (325 mg/L)
2 – Ascorbic acid (20 mg/L)
3 – Vanillin
4 – Sorbic acid (220 mg/L)
This information has been sourced, reviewed and adapted from materials provided by Lumex Instruments.
For more information on this source, please visit Lumex Instruments.