FoodO2 – Portable hand held optical system for oxygen measurements in MAP (modified atmosphere packaging)
Pharmacy Quality Packaging Control: HAND SYSTEM FOR OXYGEN ANALYSIS IN BLISTER PACKS – FoodO2
IQ & OQ documentation
Food02 is a manual needle type oxygen micro-sensor which enables micro-invasive measurements with sensor tips smaller than 50 μm. The most commonly it is used for determination of headspace and dissolved oxygen content in packages, for example in pharmaceutical industry Hand02 is used for oxygen content measurements in pharmaceutical vials, packages, and blisters.
The measurements are made with an optical oxygen micro sensor that is mounted in the tip of the needle. The needle itself is 0.8 mm wide, sharpened tip is app. 40 mm long and it punctures the blister on the flat side. There should be enough space only for the needle tip.
About the sensor
Chemical-optical oxygen sensor is designed for all research and packaging applications where a small tip size (<50 μm) and fast response time (t90<1s) are necessary. The optical oxygen micro sensor is based on a 140 μm silica fiber with a 140 μm flat-broken tip. The oxygen micro sensor is mounted in needle-type housing.
The light from the blue LED excites the sensor spot to emit fluorescence. If the sensor tip encounters an oxygen molecule, the excess energy is transferred to the oxygen molecule in a non-radiative transfer, decreasing of quenching the fluorescence signal. The degree of quenching correlates to the partial pressure of oxygen in the matrix, which is in dynamic equilibrium with oxygen in the sample. The decay time measurement is internally referenced.
Needle-type oxygen micro sensor is perfectly suited for measuring oxygen distribution with a high spatial resolution of less than 50 µm. The oxygen-sensitive tip of an optical fiber is protected inside a stainless steel needle. This design is optimal for easy penetration of tissue, septum rubber or packaging materials. After penetration the sensor tip is extended for measurement.
The oxygen micro sensor can be used for oxygen content measurement in blisters. Septa are attached to the blister to avoid oxygen from the air entering the blister. The needle of the micro sensor housing is pierced through this sealing into the blister. The tip of the needle is placed in the space between the packaging and the tablet or capsule. Then the sensor tip is expanded and the oxygen content inside the blister can be determined. This is an easy method to ensure the shelf life of pharmaceuticals and other products packed in blisters.
Another common application is the oxygen content measurement in pharmaceutical vials. Like with other packages, the septum of the vial is pierced with the needle of the oxygen micro sensor housing. Place the tip of the needle in the headspace of the vial and extend the sensor tip to take measurements. After measurement values stabilize at a certain oxygen value, you can insert the sensor further into the liquid and again wait till values stabilize.
The oxygen sensor output is very linear through the entire range of measurement. This allows for a single point fully automatic calibration to be performed anywhere in the measurement range. Span calibration is accurately done by testing room air, which should give a reading of 20.9% oxygen. Calibration standards can also be used if required by in-house test procedures.