miniGC App Note – Analysis of Vanillin by GC-FID
Abstract
The Lucidity miniGC was used to analyze imitation vanilla extract, pure vanilla extract, and the extract of a whole vanilla bean pod which was extracted using the CEM EDGE Automated Extraction System. A calibration curve of the primary flavor component of vanilla, vanillin, was constructed and the vanillin content of all samples was calculated.
Introduction
Flavors and fragrances are frequently tested compounds in food and beverages. One of the most commercially prevalent flavor and fragrances is derived from the seed pods of the orchid Vanilla planifolia: vanilla. Vanilla is heavily used in many foods, especially baked goods and sodas, and is ubiquitous in Western desserts. The ubiquity of vanilla extends beyond the food and beverage industry; the vanilla aroma is popular in perfume production and aromatherapy. The cultivation of vanilla beans is highly labor-intensive, requiring hand-pollination of the flower within 12 hours of its blooming. As the demand for vanilla flavors constantly grows, synthetic options for producing the major flavor and fragrance component of vanilla, vanillin, have been developed in order to meet market demands.
Currently, synthetic vanillin is used more readily than plant derived vanillin. The ease of synthesis for vanillin has allowed for mass market utilization of the vanilla flavor and fragrance. Natural vanilla extracts contain a large variety of other compounds aside from vanillin; however, synthetic vanillin is often solely vanillin in an alcohol. In this application note, we compare the chromatograms of injections of pure vanillin, commercially available vanilla, and extracts of the vanilla bean using the Lucidity miniGC.
Materials and Methods
Reagents
ACS-grade ethanol was purchased from Sigma Aldrich. Vanillin was sourced from Sigma-Aldrich. Vanilla beans and vanilla extracts were purchased from a local grocery retailer.
Standard Preparation
50 mg of vanillin were dissolved in ethanol in a 50 mL-volumetric flask. After ensuring dissolution of vanillin in ethanol, the solution was brought to volume with ethanol.
Sample Preparation
A whole vanilla pod was cut into segments and extracted using the EDGE Automated Extraction System with the method detailed below; an aliquot of this extract was transferred into an appropriate vial for injection on the miniGC.
The store-bought vanilla samples were diluted in ethanol and transferred to appropriate vials for injection on the miniGC. The imitation vanilla was diluted ten-fold, while the pure vanilla extract was diluted five-fold.
EDGE Method for Vanilla Bean Extraction
Q-Disc: S1 Q-Disc stack (C9+G1+C9 sandwich)
Cycle 1
Extraction Solvent: Ethanol
Top Add: 10 mL
Bottom Add: 0 mL
Rinse: 0 mL
Temperature: 80 ºC
Hold Time: 3:00
Cycle 2
Extraction Solvent: Ethanol
Top Add: 10 mL
Bottom Add: 0 mL
Rinse: 0 mL
Temperature: 80 ºC
Hold Time: 3:00
Wash 1
Wash Solvent: Ethanol
Wash Volume: 20 mL
Temperature: —
Hold Time: –:–
Analysis
GC Method
Table 1. GC Method
| Parameter | Value |
| Column | Restek MXT-5 30 m, 0.25 mm ID, 0.25 µm (cat.# 70223) |
| Injection Volume | 1 µL split (split ratio 20:1) |
| Liner | Restek Topaz 4.0 mm ID Low Pressure Drop Precision Inlet Liner w/ Wool |
| Injection Temperature | 250 °C |
| Carrier Gas | H2, constant flow |
| Flow Rate | 1 mL/min |
| Oven parameters | 80 °C (hold 1 min) to 225 °C at 10 °C/min (hold 2 min) |
| Run time | 17.5 min |
| Detector Temperature | 300 °C |
Results and Discussion
Figure 1. The chromatogram of vanillin standard calibration curve injections.
Figure 2. The calibration curve of vanillin in ethanol. The curve was constructed from 6 points with concentrations of 100, 125, 250, 500, 750, and 1000 µg/mL.
Figure 3. The chromatogram of imitation vanilla extract.
Figure 4. The chromatogram of pure vanilla extract.
Figure 5. The chromatogram of vanilla bean extracted on the EDGE system.
The Lucidity miniGC was able to create a calibration curve of vanillin with strong linearity and analyze imitation vanilla extract, pure vanilla extract, and extracted vanilla beans from the CEM EDGE Automated Extraction System. The chromatogram for imitation vanilla extract featured two prominent peaks. The earlier eluting compound from the imitation vanilla is vanillin, while the later eluting is most likely ethyl-vanillin, another commonly synthesized vanilla flavor, or acetovanillone, a minor product from vanillin synthesis. Both the pure vanilla extract chromatogram and the extracted vanilla bean chromatogram have prominent vanillin peaks as well as other smaller peaks. These peaks are most likely other flavor compounds in the vanilla plant.
Table 2. The concentration of vanillin in extracts.
| Sample | Vanillin concentration (µg/mL) | %RSD (n=5) |
| Imitation vanilla extract | 414.16 | 0.07 |
| Pure Vanilla extract | 552.86 | 1.12 |
| Extracted vanilla bean | 435.03 | 0.97 |
Conclusion
The Lucidity miniGC was able to analyze vanilla extracts for their respective vanillin content. In conjunction with the CEM EDGE Automated Extraction System, the vanillin content from 3 samples was analyzed.
Download app note here: miniGC App Note: Analysis of Vanillin by GC-FID