Zebrafish Embryo Medium

[frida]

Hello everyone,

Sorry this is slightly off topic but it's driving me nuts. In our lab, when we grow embryos from when they are born to about day 3, we keep them in a solution which contains the following:

5mM NaCl, 0.17mM KCl, 0.33mM CaCl2.2H2O, 0.33mM MgSO4.7H2O + 0.2ppm methylene blue

We usually make it by making a 60x stock solution:
To make 1 litre:
17.2g NaCl
0.76g KCl
0.29g CaCl2.2H2O
0.49g MgSO4.7H2O

I'm really confused at the moment because whenever I do the calculations, I get 0.033mM of CaCl2 and also MgSO4. The 0.33mM value is the published one and I'm inclined to think it's correct so where am I going wrong??

What I've done:
for CaCl2.2H2O
molecular weight = 147g/mol
therefore: (1/60)x(0.29g/147)=0.000033mol
0.000033M=0.033mM

How did they get 0.33mM???

 

[Bignose]

There is probably a typo somewhere. Either they meant 2.9g (instead of 0.29 g) or they dropped a 0 in the reported mmol figure. Typos do happen.