4KH Solution for drop checkers...

[BPASCreighton]

I am fortunate enough to work at a lab with a VERY accurate balance. The balance is accurate enough to measure 71.2mg of baking soda which when mixed with 1L of water will give you a liter 4KH solution to use in you drop checkers. It'll last you a long while. It I get swamped with orders I may ask for shipping money, but 71.2mg isn't going to cost much to mail . PM me if you're interested.

[Anti-Pjerrot]

71,2 mg of baking soda dont give a kH 4 solution.

You need 75,82 mg Na2CO3 ad 1000mL

4 kH equals 71,43mg/L CaCO3.

Using 99,8 % pure anhydrous Na2CO3 is best, so recalculate that from the molar equivalent of CaCO3:

M Na2CO3 = 105,99
M CaCO3 = 100,087

71,43 x (105,99/ 100,087) = 75,64mg/L

Recalculate for purity:

75,64/0.998 = 75,8mg/L

The best way is to make a stock solution and dilute so you can make several batches.

Weigh off 757,9 mg Na2CO3 and dissolve to 100,0mL with MQ water (Class A measureing bottle) stir with a magnet for 1 hour. Add 10,0mL to a 1000,0mL Class A measuring bottle and fill with MQ water.

Depending of the quality of your glassware, you can dilute the Na2Co3 to 1000,0mL first, and add 100,0mL to 1000,0mL (10 x dilution). But usually the 1000,0mL measuring bottles has less accuracy.

Best regards - the R&D labtechnician

[BPASCreighton]

Thanks Anti-Pjerrot, I would hate to send anyone crap .

So...is it possible for me to make a 4KH solution using baking soda?

The lab I work in is a microbiology lab and I'm not sure if we have the anhydrous Na2CO3. We have Erlenmeyer flasks with the 1L etchings that are very accurate, but if I'm mailing it to other people I'd like to send them 100mls of the stock solution and just have them add 1L of distilled water using a bottle of water or something easy and cheap. We have some large pipets that are pretty accurate at 50ml. So maybe send people 50mls of the stock solution and have them add it to a 500ml bottle of drinking water that's been reverse osmosis filtered? I'm not really sure on the difference with MQ water and RO water. Can you enlighten me? I know most bottled water has "minerals" added to enhance flavor. Do you think this will effect the accuracy of the solution significantly?

What do you think the best way for people to do this without flasks or graduated cylinders or anything else fancy?

If this catches on I can just make a more concentrated stock solution and mail out smaller amounts. Could I use .7582g anhydrous Na2CO3 in 1L MQ H20 and send people just 10mls or 5mls of the stock solution to dilute themselves? The smaller amount I have to send the better.

Anti-Pjerrot, thank you so much again for correcting me! Can I ask what you do for a living?




Sorry everyone...I was mis-informed! But if I have the Na2CO3 I'll be more than happy to mail out some stock solution.

[Anti-Pjerrot]

Im a Labtechnician in a R&D department. I work with Hyaluronic acid for Novozymes Biopolymer A/S.

Novozymes Biopolymer | Industrial benefits

Im the guy in front of the blue cabinet.

Well - there is another not so accurate but easier method. Ill post it here later on.

[BPASCreighton]

You're famous !!! Thanks again for the input.

[Orlando]

Holy Cow! thats very cool; job Ant-Pjerrot. Have any extra cool lab coats laying around

[BPASCreighton]

So I tested my solution I had made from baking soda a while back with my crappy KH test and its 4 degrees. It's not as accurate as the one made with Na2CO3 , but I think it'll work fine.

I'll send out 10ml or 5ml of the stock solution to be diluted to a 4KH solution. PM me if your interested.