I am planning to use HACH DR 6000 for spec. This is A SINGLE BEAM SPEC. The manual says run reagent blank though the options is not visible and I am trying to get a technical support for the same.
My confusion is, when we read "zero" with the instrument what sample should we use - only deionesed water, empty quvatte, only sample (without test procedure reagent) or the reagent blank (without sample)?
Which one will be the reference here, as we do in double beam spec?
If we zero the instrument with reagent blank (water + reagents, no sample) will be enough?
Turn on the Spec and allow it to warm up, Set wavelength .Prepare a blank cuvette by adding all solvents EXCEPT the substance to be measured.
A BLANK is used to calibrate the Spec, so that any absorbance attributable to the solvent and/or glass cuvette can be compensated. By zeroing the Spec to the blank, you will measure only the absorbance due to the substance.
NOTE: When taking several measurements at the same wavelength over a short time period, you do not need to reblank for each. Over longer times, however, the unit may drift and recalibration to the blank will be necessary. IF, however, you change the wavelength, you must re-zero the instrument. If you are taking readings over an extended period or sharing the instrument, re-zero for each measurement.
Mohammed Sir,
Thanks fro your answer!
What i understood from your suggestion to "zero " the instrument with a blank i.e., with all the reagents and instead of sample add water, so we can call it a reagent blank.
Now when we have done zeroing the instrument with reagent blank it will only read the absorbance created by sample.
We follow the same protocol in double beam spec, then why we add the reagent blank again in the reference cuvette? there also we zero the instrument with reagent blank!
First you must choice the suitable wavelength.. put the blank cell in it's place, and then, zero your instrument
There are several different types of blanking: water blank, reagent blank, sample blank, etc. All can be done at an individual wavelength.
As a minimum, a water blank should be performed, usually for the wavelength concerned. As the reagents may be contributing to the absorption, a reagent blank is preferable (a water blank may suffice if it is known that the reagents have the same it very similar absorbable to water at the wavelength concerned). A reagent blank has water or normal saline instead of the sample.
In some cases, the specimen itself may have an absorbable, lipaemic, icteric or haemolysis samples for example. The absorbance is calculated by replacing the reagents with water or normal saline and adding the reagent.
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