Electronic nose with polymer-composite sensors for monitoring fungal deterioration of stored rapeseed

Abstract

A b s t r a c t. Investigations were performed to examine the possibility of using an electronic nose to monitor development of fungal microflora during the first eighteen days of rapeseed storage. The Cyranose 320 device manufactured by Sensigent was used to analyse volatile organic compounds. Each sample of infected material was divided into three parts and the degree of spoilage was measured in three ways: analysis of colony forming units, determination of ergosterol content, and measurement of volatile organic compounds with the e-nose. Principal component analysis was performed on the generated patterns of signals and six groups of different spoilage levels were isolated. An analysis of sensorgrams for a few sensors with a strong signal for each group of rapeseed spoilage was performed. The ratio of the association time to the steady state was calculated. This ratio was different for the low level and the highest level of ergosterol and colony forming units. The results have shown that the e-nose can be a useful tool for quick estimation of the degree of rapeseed spoilage.

Identification of Volatile Organic Compounds and Their Concentrations Using a Novel Method Analysis of MOS Sensors Signal

“…As specified by the manufacturer, the sensor exhibits high sensitivity to VOCs and odorous gases. Sensor AS‐MLV‐P2 is also specifically designed for VOCs, but the values of its response are similar to those of sensor TGS2602 only for ethanol and 3‐methyl‐1‐butanol (Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, & Rusinek, ). Similarly, the r 2 coefficients have a low value in the case of sensor AS‐MLV‐P2.…”

“…One group contains TGS sensors 2602, 2610, and 2611, which are designed mainly for detection of natural gases. The second group consists of two TGS sensors (2600 and 2620) and AS‐MLV‐P2, which respond mainly to VOCs and general air contaminants (Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, & Rusinek, ; Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, Tadla et al., ; Rusinek et al., ). In the case of (Δ R / R ) max values, sensor TGS2611 is spaced from the other sensors, as shown in Figure A.…”

“…The operating parameters did not change during the adsorption and desorption of the substance through the sensors. The primary element of the device consists of eight MOS sensors, but only six of them strongly responded to VOCs and were therefore used in the present studies (Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, & Rusinek, ; Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, Tadla et al., ; Rusinek et al., ). The five TGS type sensors were produced by Figaro Engineering (Japan) and one MEMS type by Ams (USA).…”

“…Moreover, this type of sensors were chosen due to their sensitivity, response time, low price, and use in many devices measuring volatile compounds at different concentration levels (Fine, Cavanagh, Afonja, & Binions, ; Lippolis et al., ; Wetchakun et al., ). The same sensors were used by Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, and Rusinek () who analyzed rapeseed at a moisture level of 12.5% stored at a lower temperature (20 °C) in the studies concerning rapeseed spoilage during 31 days and Rusinek et al. () in the studies concerning rapeseed spoilage during 18 days of storage at moisture level of 9% and at a temperature of 30 °C.…”

“…Nowadays, the most popular and commonly commercially available electronic noses are built with conducting polymer and metal oxide sensors, for example, Aromascan A32S (Osmetech Plc, USA), Cyranose 320 (Intelligent Optical Systems, Inc., 1438 Arrow Hwy, Baldwin Park, CA 91706, USA), PEN2, PEN3 (Airsense Analytics, Germany), FOX 2000, FOX3000, and FOX4000 (Alpha MOS, France) (Loutfi, Coradeshi, Mani, Shankar, & Rayappan, ). Conducting polymer sensors usually exhibit a quick time of the adsorption phase (reaction time— t IM ) up to maximum responses and a quick desorption phase (cleaning time— t CL ) up to the baseline (Cyranose 320, USA) for grain VOCs research (Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, & Rusinek, ; Kubiak, Wenzl, & Ulberth, ). In turn, metal oxide semiconductor (MOS) sensors react differently to the same substances; both phases can be longer and differ in shape (Gancarz, Wawrzyniak, Gawrysiak‐Witulska, Wiącek, Nawrocka, Tadla et al., ; Loutfi et al., ; Martinelli, Falconi, D'Amico, & Di Natale, ).…”