From: "CHANDRA, Tilak" <tchandra**At_Symbol_Here**FPM.WISC.EDU>
Subject: Re: [DCHAS-L] water aspirator - vacuum question
Date: December 4, 2012 9:23:22 AM EST
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: <CAA4EBLvfWs5hw23P=k0-xeZGYOzwHH_42kQTYnR8co6yBpyyfQ**At_Symbol_Here**>

1.      Do you still use the sink aspirator/vacuum? Yes it is common practice in organic/inorganic and for degassing the buffers. You may perhaps also use Eyelet aspirator vacuum pump:

This system is good for rotary evaporator; if the condenser is cooled properly one can avoid pumping solvent into the system/sink. I used this aspirator using ethylene glycol and water mixture for condenser. Very effective for toluene, pyridine and other high boiling solvents. Also requires water cooling inside the tank. I used to put the ice intermittently during the solvent removal process. Vacuum depends on water temperature of the tank. Vacuum can reduced if low boiling solvents are used for the distillation by bleeding the vacuum from the system. This kind of manipulation requires hands-on experience.

2.      If so, what kind of trap do you use to prevent solvent or other hazardous material (liquid & vapor) from going down the drain? (Ice /ice: salt mixture, use low pressure for low boiling solvent, it is difficult to trap, methylene chloride, ether etc.)

3.      If you no longer use this filter/vacuum set up, what do you use? (Under nitrogen pressure if the system is closed; this method used only for air and moisture sensitive sensitive chemistry)

Please let me know if you have any additional question regarding the aspirators, and will be happy to help you.





Tilak Chandra, Ph.D.

Chemical Safety Specialist

EH&S; Chemical Safety

30 East Campus Mall

Madison, WI 53715

Ph. 608-890-0255

Cell:  608-622-9761

“There’s simply never an adequate excuse for not wearing safety glasses in the laboratory at all times” Dr. K .Barry Sharpless, Nobel Prize Laureate 2001.

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From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Kim Auletta
Sent: Tuesday, December 04, 2012 7:27 AM
Subject: [DCHAS-L] water aspirator - vacuum question


I need the expert opinion of chemists working with 21st century ideas!


I was in a lab yesterday in Chemistry that is run by a PI older than the hills. His lab is filtering powders and solvents using the sink aspirator. All of the tygon tubing (both sides of vacuum & flasks) is discolored and shows signs of deterioration. They say this tubing is only looking that way because its really old. There was a flask for trap set up between the sample & the sink. I tried to explain that this set up may be allowing solvents to go into the water & down the drain. They tried in their best "I'm the seasoned PhD Chemist and you're not" voices to tell me it was ok and that there was no other way to do this and that everyone, including in industry, does it this way. Really? 


So - my questions to all of you enlightened chemists:

1. Do you still use the sink aspirator/vacuum?

2. If so, what kind of trap do you use to prevent solvent or other hazardous material (liquid & vapor) from going down the drain?

3. If you no longer use this filter/vacuum set up, what do you use?


thanks for your help!


Kim Gates Auletta

Laboratory Safety Specialist

Environmental Health & Safety

Stony Brook University

Stony Brook, NY 11794-6200



FAX: 631-632-9683

EH&S Web site:


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