[m-khalili]

hi
I want to know detection of lead ion (Pb2+) in a solution by spectrophotometer without any additive is possible?

[Stepan]

Lead ion in water is colorless.

[m-khalili]

thanks for your favor
so you mean that for determining the concentration of a metal ion in a solution with spectrophotometer, solution must be colorful?
how about cobalt ?are cobalt salt solution colorful?does the solution color of cobalt salt depend on the PH of solution?
best regard

[Stepan]

Cobalt ion in water has natural colour and can be detected with spectrofotometer. The colour and its intensity depends on everything: pH, other ions, inorganic impurities (NH3, H2S, Cl,...), some organic impurities (amines, .)

[m-khalili]

thanks so much
may you please help a little more
you mean with out any addition of ligand the concentration of Cobalt can be obtain with spectrophotometer?
 how about using uv visible spectrophotometer for determining  pb2+ or  Hg2+ concentration in the solution (with out addition of any ligend)?

[BluePill]

Pb²⁺ and mercury²⁺ cannot be measured without a ligand with spectrophotometry. You could do AAS if you don't want to use a ligand.

[TheUnfocusedOne]

+1 to AAS, probably your best bet.

[m-khalili]

I havent ASS so i should determine concentration Hg 2+ and Pb2+ by UV VIS spectrophotometer UNICO 2800
can any one suggest some reasonable and availble ligand for determination by this equipment(UV VIS spectrophotometer UNICO 2800_ wavalength range 190_1100 nm and spectral bandwidth of 4nm)?

[m-khalili]

I havent ASS so i should determine concentration of Hg 2+ and Pb2+ by UV VIS spectrophotometer UNICO 2800
can any one suggest some reasonable and availble ligand for determination by this equipment(UV VIS spectrophotometer UNICO 2800_ wavalength range 190_1100 nm and spectral bandwidth of 4nm)?

[aeacfm]

i think additives to produce coloure is a must!!!

[m-khalili]

may you please suggest an additive:

[aeacfm]

depending on your field:
http://www.google.com.eg/#hl=ar&source=hp&q=spectrophotometric+determination+of+lead&oq=spectrophotometric+determination+of+lead&aq=f&aqi=&aql=t&gs_sm=e&gs_upl=2752l14404l0l40l37l0l21l21l0l547l3202l2-3.3.2.1l9&fp=6f6203ab33971ce&biw=1366&bih=535

[m-khalili]

though  cobalt salt are colorful,but I have read in some paper which researcher have added some additive  for determining cobalt concentration in solution,you think whats the reason?

[Stepan]

Cobalt and some other ions can be DETECTED in solution without any additional ligands, anions, or reactions. But result is qualitative and usually not sensitive enough.

When you use extra steps of analysis by introducing co-reagents, you increase selectivity, accuracy and sensitivity tremendously.

This is very old area of chemistry developed in 1890-1940's. The methods are well developed. Check the handbooks of analytical chemistry on-line or in your library

Regards

[m-khalili]

tanks
may you please introduce some useful study source for Pb2+ and Hg2+ ligand?