The self-zeroing buret is the key piece of labware you will need for a very accurate, easy to use Titration Station. The buret is a graduated glass cylinder that gives a reading accurate to 0.1 milliliters. It is easily refilled and it always resets itself to zero. During titrations, you simply open the buret’s valve allowing titrant to slowly drip into your sample. No need to count drops because when your titration goes to completion you just read your result from the graduations on the cylinder. It is fast and allows you to easily perform several titrations which can then be averaged so you are assured of using the correct amount of catalyst for your biodiesel transesterification.
The preparation of titrant (commonly 1g NaOH or KOH per 1000ml water) and sample (typically 1ml of oil in 10ml isopropyl alcohol) remains the same as you would normally do. The buret replaces the eyedropper used to perform titrations.
|^^^^^A black background makes it easier to read the white colored graduations on the cylinder.|
|<<<<: The self zeroing buret on a homemade stand. The stand uses broom clips from the hardware store to hold the buret in place.|
|<<<<<Squeezing the plastic bottle fills the buret with titrant (NaOH or KOH in distilled water). Fill the buret up past the zero mark and release. The titrant will now drain back to exactly zero. Prepare your sample as usual.|
|Open or squeeze the buret valve to establish a very slow drip into your sample. As soon as color change or pH jump occurs close buret valve. Read result in milliliters directly from buret graduations. This result goes into your calculation for amount of catalyst needed.|
Scientific suppliers sell many different kinds of burets at many different prices. The LaMotte company in Maryland sells this inexpensive version of self zeroing buret which uses the plastic squeeze bottle to fill. Other models use a glass bottle which incorporates a separate rubber bulb for filling the buret (more complicated and expensive). LaMotte also sells a stand to hold the buret, a homemade stand can do the same for very little money.
LaMotte sells to the public and can be reached at: 1 800 344-3100, www.lamotte.com
It is also available at: www.coleparmer.com and www.b100supply.com
|0847-24||Buret with plastic bottle and “squeeze valve”
(As shown in photos, recommended)
|0827-24||Buret with plastic bottle and glass stopcock
(Same buret with “better” valve)
|0996-24||Buret with plastic bottle and teflon stopcock
(Same buret with “best” valve)
|1090||Single Buret stand
(pr-fab stand more $$ than homemade)
Buy the least expensive buret and make your own stand, you should be right at fifty bucks for a piece of labware that will payback in convenience, speed and accuracy!