I do not understand the terminology being used here as it does not relate to HPLC. "
DAD and spectrophotometric detectors". ?
All HPLC DAD (or PDA) detectors function as, and are basically spectrophotometric detectors. So are single or multi-wavelength detectors too. So what are you comparing? Are you comparing a bench-top spectrophotometer with cuvette holder (or a cuvette with sipper tube) to some type of HPLC detector with conventional flow cell? Please explain.
Next, any comparison made between different HPLC systems, different detectors or for that matter a bench-top spectrophotometer would likely yield different data for the same samples. Specifically in their output. Besides tubing, plumbing, column and setup differences, the detectors are different too. Hardware and Software differences account for most of the changes in output.
Hardware:
The detector optical blocks are different and optimized to transmit light in different ways to the detectors (different designed used). The parts and electronics are different and setup for arbitrary outputs. the flow cells used (or cuvettes) may be made of different quartz material, usually have different path lengths and volumes. The detector's bandwidth is often different. On some detectors bandwidth is fixed, on others it is adjustable. Lamp slits are sometime used to reduce or increase the amount of lamp energy focused through the system to the detector. Again, all of these things can cause well documented output differences.
Software: There is a long list of detector software functions which can manipulate the raw or processed data output from the detector. A great example of one feature that can completely change the output (add signal, delete signal, change the entire signal obtained) is the software feature known as the "
Reference Wavelength" (not to be confused with the auto-zero that takes place at the start of a run). We see this mess up a lot of data for users, and they are often unaware that it is happening because they do not understand what the feature does.
A few links for more info:
https://hplctips.blogspot.com/2011/09/u ... width.htmlhttps://hplctips.blogspot.com/2011/03/r ... -hplc.htmlMaybe some of this answers your question, but maybe you could explain what you are comparing in more detail so everyone can understand the question better.