LabQuest 2 app was selected as a finalist in the Best Educational Use of a Mobile Device category for the 2013 CODiE Awards! The category recognizes the best curriculum or administrative application, designed for either PK-12 or postsecondary markets, that is delivered via mobile devices, including smartphones or tablets.
In order to prolong the life of your Mini GC (original or Plus), or to prevent having to send it in for repair, make sure you note the following best practices.
After receiving your Mini GC, it is best to begin with at least one experiment from the experiment book that accompanies the instrument. This will give you the best idea of compounds that come out cleanest, along with their temperature/pressure profiles.
The Hamilton syringe that is shipped with the device has a brown plastic bumper guard on the needle, also known as a needle stop. Do NOT remove this guard. Injections go straight into the column, and you can damage the instrument by forcing the syringe too far into the device.
Make sure you have referred to the list of acceptable compounds in the user guide before attempting to inject new compounds.
If you inject samples that contain more than 5% water, you will shorten the life of the detector, or you may ruin it altogether. To get the longest life out of your Mini GC, only inject between 0.2 and 0.3 μL of a pure organic sample, or 0.4–0.6 μL of a mixture of organic compounds.
If you have a particular gas chromatography application in mind, but you are not quite sure if it is appropriate for the Mini GC or Mini GC Plus, please call Vernier Technical Support at 1-888-837-6437 and ask to speak with a chemist. You can also email us at firstname.lastname@example.org
However, you can’t just mix hydrogen peroxide with a few drops of baker’s yeast and expect to get repeatable results every time. The amount of enzyme in a drop of yeast suspension depends on the number of yeast cells in each drop. This will depend on how long the yeast have grown and where the students pull each drop from the suspension. To get consistent results each time, the instructor must proof the yeast at least an hour in advance.
In addition, the suspension should be placed on a stir plate and students should pull samples from the middle of the suspension. Our resident biologists have revisited this experiment and found that purified catalase enzyme can be substituted for the yeast suspension in this exercise. This is an excellent option for investigating the effect of enzyme concentration. This is also a very cost-effective solution, as 1 g of catalase will provide enough enzyme for more than 4000 trials!
Purified catalase enzyme can be purchased from Flinn Scientific, Ward’s Natural Science, or Sigma-Aldrich. The concentration of enzyme varies from 2000–5000 units/mg and depends on the bottle.
You can mix up a stock solution of the enzyme in water. Make a stock solution of 1000 units/1 mL. For a step-by-step video on how to do this, visit Flinn’s website.
If you are using the O2 Gas Sensor for this investigation, use 0.5 mL (5 drops) of 1000 units/1 mL catalase solution for the preliminary activity. Add the enzyme to a 250 mL Nalgene bottle first, then add 10 mL of 3% H2O2. Start data collection immediately.
If you are using the Gas Pressure Sensor for this investigation, use 1 drop of 200 units/mL catalase for the preliminary activity. Add the enzyme to a 20 mL test tube or 15 mL conical tube first, then add 6 mL of 3% H2O2. Start data collection immediately.
If students are investigating enzyme concentration as an independent variable, make 100 units/mL, 1000 units/mL, and 2000 units/mL enzyme solutions.
If students are investigating substrate concentration, start with 6% H2O2 instead of 3% H2O2. This can be ordered from Flinn Scientific, Ward’s Natural Science, or Sigma-Aldrich.
Store the catalase powder as instructed. Enzyme activity may decrease from year to year, but will remain viable for up to three years.
By using these tips, you and your students will have greater success in your inquiry investigations on catalase.
Vernier Software & Technology sponsored a contest for educators to show how they are using Vernier sensors with National Instruments LabVIEW software to introduce STEM concepts, teach LabVIEW programming, or perform engineering labs in the classroom.
The prizes for the winners included $1,000 in cash, $3,000 in Vernier technology, and $1,500 toward expenses to attend the 2013 American Society for Engineering Education (ASEE) conference in Atlanta, Georgia.
Now that neuroscience is a topic covered in one of the “big ideas” in the new AP Biology curriculum, many teachers have been asking how Vernier sensors can be used to teach concepts related to neuroscience.