Monitoring oxygen permeation through polymeric packaging films using a ratiometric luminescent sensor (original) (raw)
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Chemosensors, 2018
Five types of new solid-state oxygen sensors, four based on microporous polypropylene fabric materials and one on polyphenylene sulphide films impregnated with phosphorescent platinum(II)-benzoporphyrin dye, were tested for their stability and safety in food packaging applications. All these sensors exhibit useful optical signals (phosphorescence lifetime readout) and working characteristics and are simpler and cheaper to produce and integrate into standard packaging materials than existing commercial sensors. When exposed to a panel of standard food simulants and upon direct contact with raw beef and chicken meat and cheddar cheese samples packaged under modified atmosphere, the sensors based on ungrafted polypropylene fabric, impregnated with PtBP dye by the swelling method, outperformed the other sensors. The sensors are also stable upon storage under normal atmospheric conditions for at least 12 months, without any significant changes in calibration.
Journal of Packaging Technology and Research
An attempt was made in the present study to develop and characterize sodium alginate (SA-MB-NR), sodium caseinate (SC-MB-RSS), and carrageenan (CG-MB) ultraviolet light activated intelligent oxygen indicator. Among all the sensor films, CG-MB displayed least overall migration in all the food simulants. Tensile strength of CG-MB sensor film was found to be the highest among all. FTIR spectra of the original and photo-activated sensor films revealed changes in the alkyl, amide, and hydroxyl groups. Equilibrium moisture content of the sensor films was found to be in the range of 94.73-120.26 g 100 g −1. Peleg model was found to best describe the sorption behaviour of SA-MB-NR while SC-MB-RSS and CG-MB were best described by D'Arcy and Watt model. All the three sensor films were found to be equally sensitive to oxygen concentration varying from 2 to 10% but significantly differed at 1% (P < 0.05). All the three sensor films were found to be equally sensitive to oxygen at as low as below 1% concentration. Hence, it can be concluded that film CG-MB could be potentially applied as an oxygen leak indicator for direct contact (vacuum) or non-direct contact (modified atmosphere) food-packaging applications.
Novel luminescent oxygen sensor systems for smart food packaging
2017
Polyolefins Moderate Low cost, Good stability, Easily available, Good mechanical properties Poor compatibility with common solvents, Limited process-ability Fluoranthene 65 , PtBP 56a Polystyrene Moderate Easily manufactured, Low cost, Good stability Needs support material, Highly hydrophobic leading to slow response in aqueous samples Ru(dpp) 3 (ClO 4) 2) 66 , Ir(ppy) 3 38 , PtOEP 67 , PtOEPK 40b PVC Low Good mechanical properties, Good optical properties Low O 2 permeability, Needs plasticizers which can leach Camphorquinone 68 , Ru(dpp) 3 (ClO 4) 2) 60 Silicone Rubber High Good mechanical properties , Good optical properties, High thermal stability, May be steam sterilized Cannot be easily plasticized, Poor hosts for highly polar dyes, May contain unknown components in precursor material, Final attributes affected by curing procedure Pyrene 69 , Ru(dpp) 3 (laurylsulfate) 2) 70 , Pd coproporphyrins 71 Sol-gel Tuneable Good mechanical properties, Good optical properties Poor reproducibility, Process complexity, Change in structure over time (aging) Ru(bpy) 3 72
Chromatic Sensor to Determine Oxygen Presence for Applications in Intelligent Packaging
Sensors, 2019
A chromatic sensor has been designed for the detection of oxygen in package headspace. The sensor is based on the redox change of methylene blue (MB) to its leuco form. Its formulation includes the pigment, glycerol, as a sacrificial electron donor, TiO2, as a photocatalyst and ethylene-vinyl alcohol copolymer (EVOH), as a structural polymer matrix. The final sensor design that allows its manufacture by conventional printing and laminating technologies consists of the sensing polymer matrix (MB-EVOH) sandwiched in a suitable transparent multilayer structure. The outer layers protect the sensor from the external atmosphere and allow visualization of the colour. The inner layer is sufficiently opaque to facilitate sensor reading from the outside, is thick enough to avoid direct contact with food (functional barrier), and is oxygen-permeable to expose the sensing material to the internal package atmosphere. In the absence of oxygen, the sensor becomes white by irradiation with halogen ...
Extruded phosphorescence based oxygen sensors for large-scale packaging applications
Sensors and Actuators B: Chemical, 2019
Extruded phosphorescent O2-sensitive composite materials comprising cross-linked polystyrene-divinylbenzene (PS-DVB) microspheres impregnated with Ptbenzoporphyrin dye and dispersed in low-density polyethylene (LDPE) or polylactic acid (PLA) carrier polymer are described. The sensors produced by hot melt extrusion method are specifically tailored to large-scale packaging applications and nondestructive measurement of residual O2 in packaged food products. A panel of LDPE and PLA based sensor materials in the form of extruded pellets and thin film structures were produced and their structural features and O2 sensing characteristics assessed with the view of packaging applications. The extruded LDPE film sensors were also integrated in packaging materials by heat lamination, to produce 'smart' packaging materials which also protect the sensor from direct contact with food. Analytical performance of extruded sensors was demonstrated by incorporating them in modified atmosphere packaged meat and cheese samples and monitoring residual O2 levels in these packs non-destructively with a handheld Optech® reader over product shelf life. The extruded O2 sensors show superiority over the sensors previously used or usable in packaged food products. This technology advances scaled manufacturing of optical O2 sensors, their integration in packaging platforms and cost reduction.
2011
A new dynamic accumulation method for measuring oxygen transmission rate (OTR) of packages and packaging films using fiber optic oxygen sensing technology has been developed. The method allows for oxygen to transfer through a given area of packaging or sample film and accumulate in a given volume. The test volume incorporates a florescence oxygen sensor that is measured using an optical fiber probe. The chamber is initially purged with nitrogen and then the sample is exposed to an oxygen rich gas, typically air or pure oxygen. Oxygen transfers through the sample and accumulates over time. The rate of oxygen accumulation is measured and converted into an OTR measurement for the film at the temperature studied. The new method allows for measurement of perforated films, which is not possible with the industry standard, steady-state, method described by ASTM D-3985. The new method, now embodied in commercially available instrumentation offered by Oxysense, Inc. (Dallas, TX, USA) was tes...
Trends in Food Science & Technology, 2016
Intelligent and active packaging technologies have gained attention in recent time due to increased demand by the consumers and manufacturers for sustaining the quality and safety of food products, improved shelf-life as well as real time monitoring of the packaging, storage and handling processes. In this context, phosphorescence based sensors for molecular oxygen (O 2) are important tools for monitoring of packaged products, new product development and optimisation. They allow fast, reversible, real-time and quantitative monitoring of residual O 2 levels in a non-destructive manner, being superior over alternative systems. In this review, we describe the main types of phosphorescent O 2-sensitive materials, fabrication methods and general requirements for sensors for food packaging applications. The main developments and representative examples are provided which illustrate the application of such sensors for monitoring of gaseous and dissolved O 2 in various types of packaged foods and beverages. We also compare commercial O 2 sensing instrumentation and disposable O 2 sensors currently in use.
Packaging Technology and Science, 2012
A new dynamic accumulation method for measuring the oxygen transmission rate (OTR) of packages and packaging films using robust and inexpensive fluorescence oxygen sensing technology has been developed. The method allows for oxygen to transfer through a given area of packaging or sample film and accumulate over time. The test volume incorporates a fluorescence-based oxygen sensor that does not consume oxygen and therefore does not interfere with the real-time measurement of oxygen concentration. The new method was tested against a widely used, commercially available instrument (Mocon Oxtran 2/20; Mocon, Inc., Minneapolis, MN, USA) designed around the steady-state gas permeation measurement approach described by ASTM D3985. Sample films were chosen to provide comparison over several orders of magnitude of OTR. Specifically, sample films with OTR values in the range of 10 1 , 10 3 and 10 4 ml O 2 /m 2 /day were measured, and results using the two methods were compared. Results showed that the new dynamic accumulation method provides comparable results with the steady-state method (ASTM D3985).
Chemistry of Materials, 2010
A new oxygen sensor, compound 2, was synthesized through a chemical modification of a popularly used oxygen sensor of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP). The new sensor compound 2 possesses four crosslinkable methacrylate functional moieties, enabling it to be polymerized and crosslinked with other monomers for polymer sensing film (also called membrane) preparation. Using this characteristic, compound 2 was covalently bonded to hydrophilic poly(2-hydroxyethyl methacrylate)-co-polyacrylamide (referred to as PHEMA to simplify) and hydrophobic polystyrene (PS) films. To better understand the advantages and disadvantages of chemical crosslinking approaches and the influence of polymer matrices on sensing performance, PtTFPP was physically incorporated into the same PHEMA and PS matrices to compare. Response to dissolved oxygen (DO), leaching of the sensor molecules from their matrices, photostability of the sensors, and response time to DO changes were studied. It was concluded that the chemical crosslinking of the sensor compound 2 in polymer matrices: (i) alleviated the leaching problem of sensor molecules which usually occurred in the physically doped sensing systems and (ii) significantly improved sensors' photostability. The PHEMA matrix was demonstrated to be more suitable for oxygen sensing than PS, because for the same sensor molecule, the oxygen sensitivity in PHEMA film was higher than that in PS and response time to DO change in the PHEMA film was faster than that in PS. It was the first time oxygen sensing films were successfully prepared using biocompatible hydrophilic PHEMA as a matrix, which does not allow leaching of the sensor molecules from the polymer matrix, has a faster response to DO changes than that of PS, and does not present cytotoxicity to human lung adenocarcinoma epithelial cells (A549). It is expected that the new sensor compound 2 and its similar compounds with chemically crosslinking characteristics can be widely applied to generate many interesting oxygen sensing materials for studying biological phenomena.