Can IQ Scientific stainless steel ISFET probes be used with other manufacturer’s meters?

No. The signal from the non-glass silicon chip ISFET sensor is different from conventional glass probes and special electronics are required to interpret the signal. The IQ System’s meter and ISFET probe work together as a unit.   Unlike traditional glass probes, there is no maintenance of the probe.  It is ready when and where you are! 

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What's the life expectancy of IQ Scientific's stainless steel non-glass pH probe?

The non-glass probe stores dry which increases the expected life however the life of a non-glass ISFET probe is dependent upon the user’s application and reasonable care.  With most applications, a user should expect a probe to perform to specifications for about 18 months to two years.  In applications with intermittent usage, coupled with appropriate cleaning and storage, probes have lasted over five years.

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3.

What kind of battery is required and how long does it last?

The IQ handheld and bench top pH systems use a standard 9V or AA batteries.  The miniLab pH series uses two watch-type button batteries.  These batteries lasts for over 200 hours of pH testing. AC adapters are available for the several models.

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How do I clean the ISFET pH probe?

The ISFET probe is very easy to keep clean.  Normally, rinsing the probe in deionized water then wiping dry with a soft towel or tissue is sufficient.  The non-glass probe can also be scrubbed with a toothbrush and mild detergent.  If food particles, grease, fat or other material covers the sensor, a wooden toothpick can be used to gently clean the non-glass sensor itself.  Protein buildup on the sensor can be effectively cleaned using our Probe Cleaning Solution.  If food or other material is allowed to dry on the probe tip, the stainless steel probe can be permanently damaged. 

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Can the non-glass stainless steel pH probe be used in food?

The non-glass stainless steel ISFET probe design allows the probe to be used directly in food processing without contamination as defined by the U.S. Food and Drug Administration. 

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Can the ISFET probe be used in in-line or process control applications?

The laboratory-style stainless steel pH probes are optimized for momentary pH testing.  Those probes are not designed for long-term immersion or in-line applications. 

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Do the IQ non-glass pH Systems work in low ionic strength samples?

(This question is asked because typically glass probes have not shown very good response in low ionic strength solutions).  As the ionic strength of a solution decreases, any pH measurement technology will demonstrate declining response capabilities. However, since IQ Scientific Instruments’ silicon chip sensor relies on surface effects rather than membrane diffusion effects to obtain a reading, the performance of the silicon chip sensor will be as good, if not better, than glass probes.  Low ionic strength samples are an extremely difficult application for any type of pH probe.  A gentle stirring action with the probe during measurement will help to achieve a stable reading.  Special low Ionic Strength (LIS) probes are available in all model probes. 

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What is the temperature range for IQ non-glass probes?

The reading range of the IQ Systems is -5 to 105°C.  To realized the design life of the probe, it is recommended that you try to limit sample temperatures to less than 60°C if possible.  Using the probes above 60°C reduces the useful life.

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What kind of materials will harm the FET in an ISFET probe?

Hydrofluoric acid (HF) and strong abrasives will harm the ISFET probes.  Solvents such as acetone, toluene, methylene chloride, etc., may damage the chemical-resistant epoxy at the probe tip with extended use. 

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Can you use bleach to disinfect the stainless steel pH probes?

Yes.  Soak probes for a maximum of 3 to 4 minutes in a 0.5% sodium hypochlorite solution  (a 10 to 1 dilution of deionized water to laundry bleach).  Then rinse the probe well with deionized water.  DO NOT SOAK YOUR PROBES FOR EXTENDED PERIODS IN THIS SOLUTION.  If soaked for extended periods (such as overnight) the bleach solution may etch the chemical resistant epoxy coating at the probe tip and the probe will be permanently damaged. 

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How do you remove protein build up on the "FET" of an the ISFET probes?

The best way to clean protein build up from the sensor surface is to use our Probe Cleaning Solution (PSC50).  A less desirable but satisfactory choice would be to use a dilute bleach solution as described above. (See answer #10)

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Can IQ non-glass probes be used to measure Tris·HCl buffers?

IQ non-glass probes can be used to measure Tris-HCl buffers if the probe is routinely cleaned with PCS 50 probe cleaning solution and restandardized. 

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How rugged are the IQ non glass ISFET meter systems?

The handheld field meters are encased in a shock-resistant holster and are engineered to withstand rugged environments. Some meters have a membrane keypad and are water-resistant, i.e. splashes and wet hands.  The handheld field meter carries an IP rating of 65.  Other water proof handheld meters such as the IQ 170 are completely waterproof with a rating of IP67. The probes are non-glass and manufactured from 316-grade stainless steel which resist corrosion, bending and breaking. 

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How small a sample can you read with the stainless steel pH probes?

The micro probes require an approximate 4-5mm immersion depth to obtain a reading.  With our miniLab pocket meters, you can actually obtain a reading on a single drop of fluid by dropping it into the sensor, covering both the ISFET sensor and contacting the reference junction. 

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How does the ISFET probe obtain a pH reading?

IQ Scientific Instruments’ ISFETs, referred to as "FET" sensors, are silicon chips that have several proprietary layers selectively deposited on a silicon substrate.  The final layer has an affinity only for hydrogen ions.  Hydrogen ions determine pH.  The quantity of hydrogen ions at or near the sensor surface causes an electrical effect that can be detected and measured by the appropriate instrumentation, thus pH is then very precisely derived. 

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Would you give me a more technical explanation?

The ISFET consists of a silicon semiconductor substrate with two electrical contacts (source and drain) a small distance apart. Deposited on the substrate between the source and drain is a silicon electrical insulator.  Hydrogen ions at or near the surface of the insulator will cause a variable voltage potential between the insulator and the underlying semiconductor material between the source and drain.  The variable voltage potential will be proportional to the relative concentration of hydrogen ions in the sample solution. The pH can then be derived from this voltage to a very high level of accuracy. 

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What is the warranty on the IQ Non-Glass pH Meter Systems?

Meters are warranted for three years; ISFET stainless steel probes for six months.  IQ120/125 miniLabs ISFET meters are warranted for one year. Details of the warranty, restrictions, cautions, etc., can be addressed at the time of inquiry or purchase.  

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Who has bought IQ ISFET pH meter systems that I might know?

IQ Systems are everywhere!  IQ Systems are in service in colleges and universities around the nation, in factories, laboratories, bakeries, dairies, wastewater treatment plants, oil drilling platforms, the list goes on and on.  When and where a person needs to reliably measure pH and desires non-glass ISFET probes, I.Q. systems are there.  IQ Systems all carry the "CE" mark needed for European use. 

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Is there adequate tech support if I need it?

IQ Scientific maintains full-time tech support staff and a toll-free 800 number for customers to use when technical help or assistance is needed.  We take whatever time is needed to solve your concerns with our products and to assure you that IQ Scientific Instruments stands behind our products 100%.  You won’t be disappointed in service after a sale

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Are IQ Systems approved by the U.S. Environmental Protection Agency or the FDA?

Neither agency 'approves' pH meters. The EPA does however review manufacturer’s product specifications to see if EPA's defined testing protocols can be adequately performed with the technology and instrumentation.  The EPA testing laboratory in Cleveland, Ohio has reviewed the specifications for I.Q. instrumentation and has issued no deficiencies in meeting currently approved EPA pH testing protocols.  

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Describe the sizes of the various non glass, stainless steel ISFET pH probes?

IQ Systems’ general-purpose non-glass stainless steel ISFET probes are approximately the same diameter as glass probes(12mm); ISFET micro probes have a much smaller barrel (3.8-4.8mm) suitable for test tubes, NMR tubes, etc.  The general-purpose probes are approximately 15cm in length; the micro probes are approximately 20cm in length (stainless steel portion).  Micro probes constructed for NMR tube applications are approximately 25cm (10 inches) in length.  Custom probes of varying lengths or probes with varying cord lengths can be ordered at an additional cost.   

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Do the ISFET probes automatically compensate for temperature?

All IQ Scientific Instruments ISFET probes automatically compensate the pH reading for temperature.  

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What are the applications to avoid?

Avoid long-term immersion The system is designed for momentary tests in liquids or semi-solids.  Do not use the probe for continuous measurement or in-line use.  Do not keep the probe stored in solution. Always store the probe dry.

Avoid abrasive slurries or other solutions that could physically damage the surface of the sensor. 

 Avoid the following chemicals such as Acetone1, Toluene, Methanol, Methyl Chloride, Dimethyl Formide, Dimethyl Sulfoxide, Dioxane, Hydrofluoric acid.

 Avoid static electricity or other electrical charges.  The sensor can be damaged by electrostatic discharge or charged electroplating baths.

Avoid applications where the product to be measured is too viscous as to provide good contact with the sensor surface.  The sensor is slightly recessed to prevent damage.  If the sample is very thick it may be difficult to obtain good contact with the sensor.  Results may then be erratic.

After use in meats, foods, fats, oils, blood, human or animal serum, or other compounds containing proteins, grease or oils, always clean the probe well with a toothbrush and mild detergent.  We recommend you use our Probe Cleaning Solution (PCS50) to remove protein buildup.  Rinse the probe well with deionized water.  Store the probe dry with the protective cap covering the probe tip. 

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