Compound / CAS#
Concentration (ppmv)
Minimum Flow Rate (sccm)
For a KIN-TEK disposable tube, use the following formula for concentration in ppmv:
- C = (E * Ko) / F
Where:
- C = desired concentration in ppmv.
- E = certified emission rate (ng/min) as reported on
your tube certificate. - Ko = value that corresponds to the compound-specific
Ko on your tube certificate. - F = rate of dilution flow you are using (cc/min)
For a KIN-TEK refillable tube, use the following formula for concentration in ppmv:
- C = E / F
Where:
- C = desired concentration in ppmv.
- E = certified emission rate (nl/min) as reported on
your tube certificate. - F = rate of dilution flow you are using (cc/min).
STP is a term that means standard temperature and pressure.
If you are using a KIN-TEK gas standards generator, STP is considered to be 0 °C and 760 mmHg.
Your KIN-TEK instrument has internal components that are traceable to the National Institute of Standards and Technology (NIST) and may require adjustment or calibration. All components may appear to be working properly; however each year they should be calibrated and recertified to maintain accuracy and traceability.
Your KIN-TEK gas standards generator is a precision calibration instrument that is used for producing a known gas standard for calibration of a gas analyzer or sensor. If your instrument is out of calibration, you may be producing more error than you think, therefore producing false standards.
A KIN-TEK service representative will be happy to issue you a quote to perform the annual recertification at your facility, or you may request a RMA number to return the instrument to KIN-TEK for recertification in our lab.
We suggest that you deplete the tube and then dispose of it.
To completely deplete it, place it in an open container under a fume hood and let it permeate at room temperature until empty. Once empty, you can dispose of it properly.
“Certified” tubes undergo a weight loss certification procedure that determines the emission rate of the tube by the amount of weight in nanograms lost over a given time, usually minutes. Depending on specific tube parameters and emission rate requirements, some tubes may take several weeks to certify.
The KIN-TEK certification procedure is traceable to NIST through temperature parameters and weight balance measurement devices that are directly traceable to NIST.
A “certified” tube comes with a printed certificate detailing the emission rate and the corresponding serial number of the tube. An “uncertified” tube does not get an assigned serial number, does not undergo the certification procedure, and is sold with no certificate.
No records are kept for “uncertified” tubes.
If a permeation rate is already known at a given temperature, then for each 10 °C increase in temperature, the emission rate roughly doubles. This is a rough rule of thumb for disposable tubes, and can be highly inaccurate. This rule of thumb is not linear.
Note: This rule generally only applies to disposable tubes and does not apply to refillable tubes.
A good reference for permeation tube information is Gerald D. Mitchell’s paper, “A Review of Permeation Tubes and Permeators,” Separation and Purification Methods, 29(1), 119-128 (2000).
The conversion from nl/min to ng/min is easy when using the Ko factor:
- Ko = 22.4 / MW
Where:
- Ko = desired conversion factor
- MW = molecular weight of the pure analyte
- Then, E1 = E2 / Ko
Where:
E1 = desired emission rate in ng/min
E2 = emission rate in nl/min
Ko = conversion factor as specified above
