Cleanliness in the Lab

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  • By Goldleaf Scientific
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Cleanliness in the laboratory is important and should not be overlooked. All steps should be taken to limit contamination in the lab. Filter your air, provide positive pressure to the room, wear hairnets and clean room suits. Wear gloves, eye wear, and masks. This may seem like an over complication or unnecessary work, but nobody wants to fail batch testing because they were too lazy to wear gloves. Pharmaceutical products must be held to a higher standard. Cleaning your glassware is also important not only because it helps prevent cross contamination but it also keeps contaminants out of your vacuum pump. An uncleaned cold trap is prone to contaminating your pump oil. Then you will have to change it or force flush it.


Cleaning Glassware

Many chemists often use an ultrasonic bath or harsh chemicals to clean their glassware. Limonene, isopropyl alcohol and salt is often all that is needed. Both the isopropyl and the limonene are cleaners/solvents. The isopropyl is the cheapest and most practical, but the limonene will do a better job of cleaning terpenes from the flasks and coldtraps. To clean flasks its best to use coarse salt and a minimal amount of either isopropyl alcohol or limonene (like a slurry). Swirl and shake until the salt dislodges all your solids and the solvent dissolves it. If it will not dissolve the contaminant heat up the solvent with a heat gun. Pour out and repeat until free of any visible color change of the solvent. Use tap water to clear out the salt and then add a small amount of isopropyl alcohol and shake/swirl, then pour out to remove all excess water.

A simple visual test of cleaned glassware is to pour water on the glass and watch for it to sheet off. It must be DI water or at least water with low ppm of dissolved solids (TDS), but you will notice that it will not bead but instead flows off the glassware in a sheet. Once you are confident your glassware is cleaned shake out all alcohol or DI water and dry in a clean area with plenty of ventilation and free of contamination. After dry, clean off all fingerprints and put in the oven at around 350°F for an hour or so to bake off any residual alcohol or water. This method is cheaper, gentler, and quicker than ultrasonic baths and acid/base washes although it can be somewhat more labor intensive.


Vacuum Pump Oil

Vacuum pump oil is very expensive and contaminating it can be a somewhat expensive mistake but will become much more expensive if you do nothing about it. You must be very observant in the color and condition of your vacuum pump oil. Change any discolored or milky oil right away. Create a log book for all oil changes, and repairs. Be sure to include dates, descriptions, and pictures. Follow the recommended oil change routine listed in the vacuum pump manual.


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