Re: Formula needed - Benedict's solution

From:Bryan Llewellyn

According to "Lange's Handbook of Chemistry" (10th ed., 1956), Lange, N. A.,
McGraw-Hill, NY,  there are two Benedicts' solutions, qualitative and

Qualitative (for glucose):
Sodium citrate  -  173 g.
Sodium carbonate  -  100 g.
Copper sulphate.5H2O (the blue stuff)  -  17.3g.

Dissolve the sodium citrate and the sodium carbonate in 600 ml. distilled
water.  When dissolved, dilute to 850 ml.

Dissolve the copper sulphate in 100 ml distilled water.  When dissolved,
dilute to 150 ml.

While stirring continuously, slowly add the copper sulphate solution to the
citrate/carbonate solution.

Quantitative (for sugar in urine):
Copper sulphate  -  18 g. (I presume the blue stuff, but it not specified)
Sodium carbonate (anhydrous)  -  100 g.
Potassium citrate  -  200 g.
Potassium thiocyanate  -  125 g.
Potassium ferrocyanide  -  0.25 g.

Dissolve into distilled water, and make up to a final volume of 1 litre.

1 ml eqates to 0.002 g. sugar.  I would presume some kind of titration is
used to measure the sugar, although Lange does not give it.

Clinitest tablets are essentially the same as the qualitative solution.  For
more information get a clinical chemistry text from about 1955-1965, it was
in common use at that time (I remember it well), or subscribe to Medlab-L
the e-mail group for the other lab disciplines.

Bryan Llewellyn

----- Original Message -----
From: "Adrian Biesecker" 
To: "Histonet Service" 
Sent: Wednesday, November 28, 2001 9:28 AM
Subject: Formula needed

> Hello all!
> I have a customer that is looking for the formula for Benedict's
> solution?  I have never heard of this and cannot find it in our chem.
> Data base.  If anyone knows the formula, I would really appreciate it!!
> Thanks.
> Adrian Biesecker
> BBC Biochemical
> (800) 635-4477 x13

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