Increase Lab Efficiency: Control Multiple Gases with One Mass Flow Controller

Sierra’s Dial-A-Gas® technology on our SmartTrak® 100 mass flow controller allows researchers to use one product to control 10 pre-programmed gases. Learn how a Sulfide Biologist precisely controls a custom blend of 5% H2S balance N2-with one MFC.

Imagine being suspended in time—having your metabolism slow, heart rate decrease, and temperature drop. For Dr. David Kraus, Sulfide Biologist at the University of Alabama, linearity and precision matters. Dr. Kraus and other scientists are discovering that by administering small amounts of H2S, they can buy time in suspended animation.

In 2005, Dr. Kraus decided to take his experiments with H2S to a new level. At this time, Mark Roth a scientist from the Fred Hutchinson Cancer Center in Seattle was conducting groundbreaking suspended animation experiments. Inspired by Roth's work, Dr. Kraus set out to conduct his own suspended animation experiments.

SIERRA'S SOLUTION
Based on Mark Roth's recommendation, Kraus decided that SmartTrak® 100 could deliver the precise amount of H2S to laboratory mice—too much H2S will kill the mice and just the right amount induces suspended animation, reducing their metabolism and heart rate virtually freezing their bodies in time. With the removal of the H2S, the animals "come back to life".

Most controllers are used for common standard-popular gases (air, argon, nitrogen). Dr. Kraus' testing and research uses a special blend of 5% hydrogen sulfide, 95% nitrogen with a very low flow range of 1-10 sccm, mixed into another stream of combined air and N2 mixture.

Dr. Kraus did have some concerns about the ability to accurately measure mixed gases with the SmartTrak. Sierra's Laminar Flow technology was perfectly suited for Dr. Kraus' custom blend application. Technicians at the factory could use the SmartTrak's Dial-a-Gas® capability to program a custom listing for his 5% H2S blend. Then in the laboratory, Kraus could select this programmed mixture from the Dial-a-Gas menu or use the same instrument to measure any of the other nine pre-programmed gases.

Dr. Kraus' concerns about accuracy were well-founded. His application requires the SmartTrak 100 to precisely maintain 1% accuracy from 0-10 sccm of H2S, an anesthetic gas. When delivered appropriately, H2S is beneficial but in excess can be poisonous, even lethal. With traditional mass flow controllers, gas mixtures are notorious for being inaccurate. During calibration, most instruments are "curve-fit" to the application because they are not linear. They are calibrated with a primary gas, but a gas mixture has different properties than the primary gas, so the original curve is not correct for the mixture. Sierra's Laminar Flow technology, however, creates a linear relationship that allows the K factors programmed into the SmartTrak 100 to correct for any gas blend over the entire flow range. The 100 is so linear that it's only calibrated at zero and full scale.

Dr. Kraus installed his 100s to precisely deliver small amounts of H2S to his laboratory mice. Sierra's powerful solenoid valve gives the SmartTrak 100 this type of precision control and accuracy even at the very low flow range of 1-10sccm. No mice died from the toxic H2S gas and all his subjects reached suspended animation, a SmartTrak 100 success.

Just like Mark Roth, Dr. Kraus observed a suspended animation-like state in his laboratory mice. Their heart rates decreased from 650 to 50 beats per minute and their breathing rate dropped from 140 to 20 breaths per minute. Their metabolic rate and core body temperature also decreased, suspending their body in time. And when the H2S was removed, the mice came "back to life" According to Dr. Kraus, these suspended animation breakthroughs will change the face of the medical field. He believes "this may be one of the most important medical breakthroughs of this century."

In 2007, Dr. Roth received a MacArthur Genius Award for his work with H2S induced suspended animation using the Sierra SmartTrak 100.

Here' what makes Sierra's SmartTrak 100 an ideal choice:

• Patented, inherently linear Laminar Flow Element (LFE) design
• Provides smooth and flexible valve performance
• Pilot Module allows user to switch between ten pre-programmed gases, change setpoint value and source, set zero, span and full scale, modify engineering units, choose output signal...and much more
• Has more robust electronics than other industry mass flow controllers