Hi Jahangir,
My answers below.
best of luck,
Greg
- When purchasing heavy metals from companies such as Sigma, does it matter if the metals are in the form of a monochloride or trichloride? Would this affect the conjugation process in any way?
**Yes, it matters quite a bit. You need to buy a salt that will disassociate into a 3+ metal ion for optimal chelation. Most of the lanthanides only form 3+ cations, but a few salts are in other oxidation states and will not chelate correctly 4+ ions are typically fine, but 2+ or 1+ cations often will not stay chelated.
- Also sometimes these metal salts also have water molecules bound to them and they're in the form of a salt hydrate, such as Dysprosium(III) chloride versus Dysprosium(III) chloride hexahydrate (both found here -
https://www.sigmaaldrich.com/catalog/se ... us=product). Does the latter affect the conjugation process in any way? And which is more preferable for conjugating?
**You'll be dissolving the salts in water, so it won't matter if you start with a hydrate as long as the salt is in the correct oxidation state (i.e. (III)), and as Mike points out, you use the correct molar amount of metal. Typically, the hydrate is more water-soluble and thus a better choice. I'm not sure why you would buy Dysporsium from Sigma though; it will be a mixture of 7 isotopic states: 0.056% 156Dy; 0.095% 158Dy; 2.329% 160Dy; 18.889% 161Dy; 25.475% 162Dy; 24.896% 163Dy; 28.260% 164Dy.
- Does it matter which salt is bound to the metal? I.e. if you buy it in the form of a fluoride, iodide, bromide, nitrate, acetate, chloride, sulfide, etc, would any of these have an affect on the conjugation process? (I know that metals in the oxide form won't work at all in the conjugation process). And which is the most preferable/optimal form when buying metals to conjugate antibodies to?
**I'd agree with what Mike just posted on this. What matters is the oxidation state and solubility; you need the salt to be water soluble. The associated anion doesn't matter much and will be washed away in the buffer exchange after polymer loading.
- And if you're buying metals in the form of a nitrate, does that mean you would have to dissolve it in a similar acid (such as nitric acid for nitrates or hydrochloric acid for chloride) or can you simply dissolve this is MaxPar water also?
** If the metal salt dissolves in L-Buffer or water, you don't need any acid at all. In the unusual cases where acid is needed, we've dissolved in both HNO3 and HCl, but I would agree with Mike's point about rare cases where the nitrate is soluble and the chloride isn't, so nitric acid might be a safer bet.