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Neofox Oxygen sensor
NEOFOX Phase Fluorometer couples to all of our fiber optic O2 sensors.

NEOFOX connects to your PC through a USB port to provide real time O2 measurements, data recording and calibration wizard.

NEOFOX is also available in a portable system with built in display and battery, and a GT version for control by RS232.

What's New!
Measuring O2 in organic solvents has long been a challenge. Our new HCR chemistry is the most rugged and resistant formulation in the world!

HCR works in toluene!, the gold standard of agressive hydrocarbon environments.

HCR even works in acetone! Other optical oxygen sensor formulations dissolve in seconds when exposed to acetone.

Disposable O2 sensors!

disposable optical oxygen sensor

Our new plastic fiber Zero Drift AP sensors are very inexpensive, low cost enough to be considered disposable. Low cost plastic connectors and PMMA optical fibers come in a variety of diameters.  We also offer low cost borosilicate fiber sensors for applications where plastic won't hold up.

All of Zero Drift Products are available from our online store.

We also accept credit card orders by phone or purchase orders.

Call us!

727-230-1697
info@zerodriftsensors.com





ZeroDriftSensors.com
727.230.1697  info@ZeroDriftSensors.com
460 Boulder Falls Lane, Jasper, GA 30143
 New! Breakthrough HCR sensor works in toluene and acetone!
See us at ACS in New Orleans!  Booth 1406 with Wasatch Photonics

Oxygen Sensors -- Fluorescence Quenching
 Our oxygen sensors use the quenching of fluorescence by collision of molecular oxygen with a fluorophore that is trapped in an oxygen permeable polymer. This technique is superior to electrodes, in that O2 is not consumed. The sensing material can be put on the tip of an optical fiber, or made as a thin film on flat substrates (patches). We have a variety of sizes and shapes but they all work by the same principle. The NEOFOX "reader" is a phase fluorometer, which pulses a blue LED and measures the red fluorescence lifetime (tau) of the return signal. There are two chemistries available, ZERO-DRIFT AP for general purpose use in gases and aqueous based samples, and HCR for use in aggressive hydrocarbon solvents.

ZERO-DRIFT AP Chemistry This is our best sensor yet! Our breakthrough multi-layered formulation has virtually no drift due to photo-bleaching. It is not influenced by water vapor, and so it can be calibrated in gases and used without error in liquids. It is very resistant to prolonged exposure to elevated storage and operating temperatures.

HCR Chemistry  HCR is formulated to work in organic solvents, which interfere with standard formulations. It features excellent adhesion in alcohols, jet fuels, toluene, acetone and many other hydrocarbons. We can test our probe in your solvent to validate its use. Just give us a call.


Sensing chemicals with Light, how it works!
fluorescence phase delay measure O2

Oxygen is sensed from the fluorescence decay rate of a trapped metal-organic fluorphore. A blue LED pulse is sent down the fiber to the tip, or to a patch with a polymer or sol-gel matrix encapsulated fluorophore. The blue light causes a red fluorescence. The red fluorescence decays over micro-seconds of time. Collision with O2 molecules causes quenching, and a faster decay rate. If the LED is modulated, the fluorescence signal is also modulated but with a phase delay that is related to the lifetime. In the absence of O2 the lifetime is long, as the partial pressure of O2 increases, the lifetime gets shorter. The relationship between lifetime and pO2 follows a Stern-Volmer relationship. Tau(0) is the lifetime in the absence of O2, Tau is the lifetime in the sample, pO2 is the partial pressure of O2 and Ksv is the sensor calibration coefficient.



Calibrations
In practice, the linear form of the Stern-Volmer equation above is not accurate over a large range of pO2 values. Instead the calibration data is fit to a quadratic equation, and at least 3 calibration points are required.

If temperature compensation is required, then a calibration matrix at at least 3 pO2 levels and two temperatures are required.

We offer factory calibrations for the probes, or you can do the calibrations yourself. Generally you will need a source of gases with known O2 concentrations, and a water bath, incubator or some other means to control temperature. We can help you design your calibration apparatus, so feel free to call us.

Our chemistries are extremely stable, and once calibrated should maintain calibration for a long time period. However, damage to the probe material, switching to a new set of optical fibers or other pertubations could cause a "shift" in calibration. When that happens a simple single point "reset" can be performed.

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