Gas Sensors. Food and Feed Safety at the IME. 1st FoodSpot Workshop 2009 January 22nd, Aachen / Germany Dr. Mark Bücking. Seidel. Seidel.

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1 Gas Sensors Food and Feed Safety at the IME Seidel Seidel Seidel Seidel Seidel Seidel 1st FoodSpot Workshop 2009 January 22nd, Aachen / Germany Dr. Mark Bücking

2 Food and Feed Safety Aim: Development and Improvement of Detection Methods (Environment, Food, Feed, Consumer Gods, Soil) Trace analysis and fast detection methods (M. Buecking) sensitive reproducible cheap fast long-living robust and simple biochemical and molecular biology based methods (B. Seidel)

3 Food and Feed Safety Research Areas Dr. Mark Bücking Complex reference analysis of organic residues Sensor Hz Flavour research Sensor Sensor 2 Sensor 7 0 Sensor 3 Fast detection methods e.g. online detection of volatiles Gas Sensors / Electronic Nose Sensor 6 Farm-side Pa-ripe Sensor 5 Pa-unripe Sensor 4 Transport Food Chain Management check check Process-control check check

4 Gas Sensors - research projects Food quality control fruit, vegetables, meat, fish harvesting, processing, transport, storage Microorganisms Air quality identification by their volatile metabolism products identification of pollutants

5 Gas Sensors the principle sample input Sensitive layer Transducer Signal & Output

6 Electronic nose Gas Sensors the definitions An instrument which comprises an array of electronic chemical sensors with partial specificity and an appropriate pattern recognition system capable of recognizing simple or complex odours (Gardner, J.; Bartlett, P.; Sens. Actuators 18, ) Metal Oxide Sensors when volatile compounds are adsorbed onto the surface of the semiconductors this generates a change in the electrical resistance which varies with the type of volatile compound and its concentration. O 2 SnO 2 O -

7 Gas Sensors the starting point Area [mv*min) Sampling time Sample prep. Data evaluation Chromatogram overlay 2 and 14 days of storage time

8 Gas Sensors conclusion Area [mv*min) time Do I know all the components in the headspace and their major interferants Do I know which components are responsible for the effect Do I know the concentration range typical of the problem I want to solve If I do not have this information it can be very dangerous and misleading to start any type of measurement with an electronic nose system

9 Gas Sensors: measurement system Setup 1 sampling 2 drying agent 3 GC column 4 gassensor array 5 data evaluation Fh-IPM

10 Gas Sensors: results 1,40 1,35 Methyl pyrrole and Ethyl butyrate Cooperation with Fh-IPM 1,30 R/R 0 1,25 1,20 1,15 1,10 1,05 Pinene Limonene concentrations: 720 ppb Methyl pyrrole 399 ppb Ethyle butyrate 66 ppb Pinene 22 ppb Limonene 1,00 T operate = 450 C 0,95 0, time/min reaction of IPM CTO sensor Very sensitive fast selective reproducible easy handling

11 Gas Sensors: example traceability Classification of peanuts Classical sample A B C Chemical assay method peroxide value (0.125mmol O 2 /kg) acid value (mg KOH/g) free fatty acids in fat (g/100g, calc. as oleic acid) n.n Fatty acids (g/100g) saturated fatty acid unsaturated fatty acid polyunsaturated fatty acid trans fatty acids <0.1 <0.1 <0.1 Gas Sensor A B B old C Scores for PC #1 (72,8%) Routine analysis is not able to clarify origin and age volatile compounds were identified and used as indicator of origin and freshness

12 Gas Sensors: example food safety Detection of bacteria contamination Abundance TIC: Pputida2.D Pseudomonas putida - SnO2+Pt (12V) MeSH Widerstand R Propan-1-ol MeSH Aceton EtOH Zeit [sec] Time--> gas chromatography 48h Metal oxide sensor 6h Routine analysis is much more time intensive volatile compounds were identified and used as indicator of bacteria species

13 Gas Sensors conclusion Gas Sensors can provide rapid sample discrimination Variables of the system are well known Nature of test and analyte are important Vendors tend to oversell this technology for any type of application Not possible! Important: transfer from technology platform to industry device handheld.autosampling.long term stability.etc

14 THANK YOU Dr. Mark Bücking Fraunhofer IME Auf dem Aberg Schmallenberg-Grafschaft Germany Tel.: / Fax: / Mobile: mark.buecking@ime.fraunhofer.de