Skip to main content
10 votes
Accepted

What do double rings mean on a pipette?

The pipette is a "blow out" type, denoted by a set of two rings printed on the upper end, meaning that a rubber bulb should be used for blowing. If there are no rings on the upper end of the ...
Ronith's user avatar
  • 1,528
9 votes
Accepted

Why are amber bottles used to store Water for HPLC?

As explained in the comments, brown bottles for HPLC, or LC-MS grade water absorb useful wavelengths for algae growth (red and blue). This is where chlorophyll absorbs. This graph shows a quantitative ...
ACR's user avatar
  • 41.6k
8 votes

What does the blue square on a volumetric flask mean?

The etch mark truly could be blue (or in an other color). But (arguably) it is more common to find such an etch mark in plain white on glass ware, for instance beakers, or flasks, or bottles, or ...
Buttonwood's user avatar
  • 30.4k
7 votes
Accepted

Why don't oils use plastic droppers?

It is (not always but often) about mutual chemical/physical compatibility. Glass vessels/accessories are generally used as general long term storage material in analysis of trace amounts of organic ...
Poutnik's user avatar
  • 42.7k
7 votes
Accepted

What does the blue square on a volumetric flask mean?

One of the ASTM International requirements, formerly known as American Society for Testing and Materials, is: ASTM E288 - 10 Standard Specification for Laboratory Glass Volumetric Flasks. 4.5.3 ...
ACR's user avatar
  • 41.6k
6 votes
Accepted

How can I read an Anschütz/Bennert manometer and how can I make sense of it?

All operations should be gentle: open the valve to the system evacuated if the vacuum applied is good enough, the level of mercury in the right hand (open) leg rises, the level in the left hand (...
Buttonwood's user avatar
  • 30.4k
4 votes
Accepted

Identifying Name/Purpose of piece of ellipsoid glassware with internal tube?

What you got there is a tilting head dispenser/tilting pipette dispenser. You are lucky that you found one for €1 because it usually costs around $20. It is small in size because it is to be fitted on ...
Anjankumar's user avatar
4 votes
Accepted

When Should you use grease to lubricate ground glass joints?

The greasing is not needed for the specific cases of steam distillation of volatile essential oils, perhaps should be even avoided. Using light greasing(*) of glass joints (not limited to ...
Poutnik's user avatar
  • 42.7k
4 votes

Is it safe to use borosilicate lab glass as an autoclave?

The temperature and temperature rate of change in an autoclave should definitely not be a problem with borosilicate glass. However, the pressure might be an issue, (if you mean 15 PSI gauge, that is, ~...
DrMoishe Pippik's user avatar
3 votes
Accepted

Changing of water in the Rotary Evaporator RC 600 affecting its performance

Independent of esthetics and chemistry, help the creature to get out of the bath. On occasion i) a round bottom flask accidentally slides out of your hand and drops into the bath. Or ii) a clip fails ...
Buttonwood's user avatar
  • 30.4k
3 votes

Why don't oils use plastic droppers?

Some plastics are attacked or degraded by certain oils, which might ruin the dropper or make the oil unsafe by leaching chemicals into it. Glass is used because it's inert - the only chemicals that ...
Sir Thinksalot's user avatar
2 votes

How to attach soft tubing to glass

You do this with great care, putting rubber or plastic tubing onto glass tubing or taking it off is a major cause of injuries in a chemistry lab. I always saw that the most dangerous object in my lab ...
Nuclear Chemist's user avatar
1 vote

Why potassium carbonate breaks glass when heated?

If the beakers are not made of borosilicate glass, it will react with the metal carbonate and break the glassware: Fusion with an alkali metal carbonate, usually anhydrous sodium or potassium ...
Nilay Ghosh's user avatar
  • 26.3k
1 vote

Is it critical to match vacuum pump oil to specific pump?

Yes, it is critical to match vacuum pump oil to the specific pump. Different vacuum pumps have varying operational requirements and design considerations. Pump manufacturers provide recommendations ...
spammer's user avatar
  • 11
1 vote

What is the fabric in heating mantles made of?

Early laboratory heating mantles use glass fiber yarn knitted material with a heat resistant naturally occurring fibrous mineral called asbestos. Modern heating mantles have found their alternatives ...
Anjankumar's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible