Oxygen Transmission Rate Measurement Using Oxygen Sensitive Fluorescent Tracers, 2004 PLACE Conference

Measurement of oxygen transmission rate through finished packaging by the use of Fibox fluorescent tracer technology is evaluated against reference values obtained on a Mocon Oxtran 2/20 MH. The Fibox has the advantage of allowing samples to be dissociated from the measurement device. This permits running a large number of specimens simultaneously. In addition, the oxygen sensitive foils used are temperature resistant up to 130°C, thus permitting measurement of oxygen uptake during retorting. A method for intermittent measurement of oxygen partial pressure in gaseous headspace of nitrogen flushed beverage bottles is presented. A metal bottle closure integrating an oxygen sensitive foil was developed and characterised in terms of its permeability to oxygen. The evolution of the gross oxygen transmission rate (GOTR), i.e. the total oxygen transmission rate of the sample, including the bottle closure, with the time of measurement was investigated for three different sensor foil calibration routines: individual calibration of sensor foils, the average values from individual calibration and the values supplied on the factory calibration sheet delivered with the sensor foil. After 27 days of measurement using individual sensor spot calibration the GOTR’s measured on the Fibox where found to overshoot the Oxtran results of 0.0068 and 0.0027 cc/(pack·day) by 36% and 106% for high and very high barrier bottles respectively. The OTR values for the three calibration routines, i.e. deducing the bottle closure permeability from GOTR, can be considered equal to Oxtran results for all three calibration routines. Statistical analysis of means and variances showed that the use of individual calibration values resulted in equal performance as the reference method after 11 days of measurement, whereas the average calibration value as well as the factory calibration only reached equal performance to the reference method after the full measurement period of 27 days. The labour intensity and the time frame within which reliable results can be obtained is higher than that of the reference method. Nevertheless, although currently not yet at par with the measurement performance of the reference method, the Fibox shows interesting potential, especially for laboratories with a limited financial resources, and will with further experience and development become a viable alternative for oxygen transmission rate measurements.