[ForensicInTraining]

A standard curve was produced using absorbance values of prepared standards obtained by UV spectrophotometry. The standards were made using concentrated hydrochloric acid as opposed to the 1N HCl that the lab manual says should be used. Because of this my absorbance values are all over the place decreasing when they should be increasing. I thought the effect of the concentrated acid would cancel as I used the concentrated acid as the reference but it appears that was not the case. Does the high concentration of the HCl effect the beers law relationship? I'm trying to research but not coming up with anything. I'm trying to explain in my discussion how the error affected my results. Any help is greatly appreciated.

I wasn't sure which topic to put this under so any suggestions to better address the problem in a different topic is appreciated as well. Thanks!

[Corribus]

It would be helpful to know more about what you're doing. E.g.: You're measuring absorbance values of what?

[Arkcon]

It really depends on what you're analyzing.  If the concentrated acid destroyed a chromophore, then yes, that could be the reason you don't get signal, keeping the blank the same notwithstanding.  Also, the dilute acid my be used to bring the chromaphore to a certain pH state for maximal signal.  Your concentrated acid may have taken it beyond. 

On a completely unrelated topic -- holy crap! Be more careful. Concentrated hydrochloric fumes strongly, no one wants to be breathing that.  If you spill some 1 N HCl, you can wipe it up and rinse off you skin at youe leisure.  Concentrated HCl will burn you faster than you can get to the sink.

[Corribus]

Not to mention, concentrated acid fumes can wreak havoc with delicate instrument components and optics. HIGHLY recommend you use sealed cuvettes when working with acids... hell, with anything, because solvent fumes can do a lot of damage over time as well.