[ryagan]

I'm working on perparing SBF in my school's lab however a couple of components are missing which are NaHCO3 (0.350 g) and K2HPO4 (0.228 g) .
Is it possible to replace these components with NACO3  and KH2PO4 ?

Table 1. Ion concentrations (mM) of SBF and juman blood plasma
Ion   Simulate Body Fluid   Blood plasma
Na+   142.0    142.0
K+   5.0    5.0
Mg2+   1.5    1.5
Ca2+   2.5    2.5
Cl-   148.8    103.0
HCO3-   4.2    27.0
HPO42-   1.0    1.0
SO42-   0.5    0.5

I'm not a chemist and I would really appreciate your view on this.

[Arkcon]

Basically, I wouldn't substitute, just because you'd now add another layer to your experiment -- verifying that your change doesn't have an effect, in addition to your actual experiment.

You may be able to find a published protocol that uses the salts you have.  Many people publish new procedures all the time.

You can see from your table, in two cases, the concentration of ions isn't as critical, so its up to you what you want to change, and how you want to do it.

[Babcock_Hall]

You might be able to get to the correct pH, but the ratio of sodium to potassium ions might be off.  I agree with Arkcon.