Expanded Fruit Fleuressence Analysis using the zNose

Fast Analysis using 10ps2a1b method

Principal chemical components can be analyzed within 20 seconds using the zNose column by ramping it from 40°C to 160°C at rate of 10°C/seconds, with a relatively a low sensitivity sensor temperature of 60°C and a 1 second sample. Figure 1 shows the 10ps2a1b method and system parameters.

Figure 1. 10ps2a1b method and system parameters.

The fruit fleuressence chromatogram (Figure 2) obtained using the fast method showed three major compound peaks with concentrations of 34,982, 22,317 and 19,439 counts and indices of 1111, 1329, and 1461, respectively.

Figure 2. Chromatogram of Fruit fleuressence.

The chromatogram also displayed significant minor compounds with indices of 830, 1054, 1219, 1274, 1542, 1651, 1804, and 1994. It is possible to measure approximately 11 principal components or compounds using the fast method.

Polar olfactory diagrams (VaporPrint®) can be created using aroma chemistry. The radial dimension in these diagrams is proportional to chemical concentration or aroma impact. The retention time (index) is mapped by the angular dimension, starting and ending at the 12 o’clock position.

It is possible to display aroma impact (radial distance) as a logarithmic or linear image (Figure 3). Using olfactory images, aroma chemistry can be visually displayed in a user-friendly manner for perfumery experts.

Humans are experts at evaluating and comparing visual figures. The combination of such comparisons and olfactory impressions provides a much-improved ability to the perfumer to judge the final product.

Figure 3. High-resolution VaporPrint® images provide a visual pattern representing aroma impact and chemistry.

Tools for forming arrays of virtual sensors specific to each aroma type can be provided by the software. Using each sensor, the concentration of a specific chemical present in that aroma can be measured and the quality of that chemical mixture can be rapidly assessed.

Bands or regions are placed over the main chromatogram peaks to graphically design the principal chemical components of fruit fleuressence (Figure 4).

Figure 4. Virtual chemical sensors the concentration of an aroma’s principal components.

Each peak is given a user-defined name containing the retention index of the peak. Once defined, the concentration of each principal chemical component of an aroma can be recorded, tracked, and displayed by the sensor array.

The principal components of each type of aroma create an array of virtual sensors specific to that fleuressence base or type. Once defined,

  • The sensor array readings can be monitored
  • Thresholds can be defined
  • Factors can be scaled
  • Alarm values can be set without the need for viewing the chromatogram

For instance, Figure 5 shows a virtual sensor array for the 8 principal components of the fruit fleuressence aroma.

Figure 5. Virtual sensor array using the 8 principal components of the fleuressence aroma.

Comprehensive analysis using 3ps2a1b method

A comprehensive chemical component analysis of the mixture aroma can be performed by extending the analysis time to 50 seconds by ramping the zNose column at rate of 3°C/seconds and using a high sensitivity sensor temperature of 20°C. Figure 6 shows the 3ps2a1b method and system parameters.

Figure 6. 3ps2a1b method and system parameters

Figure 7 shows the n-alkane response for indexing using the 3ps2a1b method.

Figure 7. Alkane perfume response using 3ps2a1b method.

Figure 8 presents the fruit fleuressence aroma chemistry using the slower 3ps2a1b method.

Figure 8. Fruit fleuressence response using 3ps2a1b method

Using the detailed analysis, a virtual chemical sensor array for the fleuressence base displays approximately 22 distinct chemicals or sensors (Figure 9).

Figure 9. Detailed analysis showing 20 principal chemical components in aroma.

Graphical bands are used to define sensors and the resulting 22 element virtual sensor array measures the concentration and index of each chemical in the aroma (Figure 10).

Figure 10. Creation of 22 virtual sensor array for fruit fleuressence aroma.

Relative concentration comparison

In the zNose vapor analyzer, the condensation of volatile organic vapors on to a temperature-controlled crystal when they elute from a capillary column is measured using acoustic waves.

The sensitivity of the analyzer is an exponential function of retention time for volatile organic vapors that do not fully condense on the crystal surface, necessitating the correction and subsequent normalization of the measured concentration values for comparison of relative chemical concentrations. Table 1 shows such an analysis and comparison for fruit fleuressence aroma using peak No. 11 for normalization.

Table 1. Quantification of results

Peak No.

Index

Measured

Corrected

Normalized

1

522

76

1189131

264.47%

2

549

41

476666

106.01%

3

709

31

62006

13.79%

4

797

69

52423

11.66%

5

819

73

43541

9.68%

6

870

82

27909

6.21%

7

897

52

13151

2.92%

8

1004

82

6391

1.42%

9

1037

639

34645

7.71%

10

1067

45

1754

0.39%

11

1114

19345

449634

100.00%

12

1183

50

544

0.12%

13

1210

588

4754

1.06%

14

1237

101

607

0.13%

15

1274

13991

55948

12.44%

16

1328

37899

83674

18.61%

17

1413

314

314

0.07%

18

1460

75649

75649

16.82%

19

1514

24040

2108

0.47%

20

1536

12032

2770

0.62%

21

1567

7120

1584

0.35%

22

1656

200

200

0.04%

Acknowledgements

Produced from materials originally authored by Edward J. Staples, Electronic Sensor Technology, CA, USA.

About Electronic Sensor Technology

Electronic Sensor Technology

Electronic Sensor Technology, Inc has developed and patented a breakthrough chemical vapor analysis process. This process applies gas chromatography calculations and technology toward a wide variety of industries, including Homeland Security, Life Sciences, Chemical and Petrochemical, Food & Beverage and Environmental.

How does gas chromatography work? With rapid, accurate analysis of chemical odors and vapors, this patented technology helps to provide real-time analysis for quick response solutions.


Sponsored Content Policy: News-Medical.net publishes articles and related content that may be derived from sources where we have existing commercial relationships, provided such content adds value to the core editorial ethos of News-Medical.Net which is to educate and inform site visitors interested in medical research, science, medical devices and treatments.

Last updated: May 22, 2017 at 3:09 PM

Other White Papers by this Supplier