Both are in fact UV/VIS detectors. Perhaps you are asking which is more sensitive, a single wavelength UV/VIS detector or a full scanning diode array detector (aka: DAD or PDA)?? A purpose built single-wavelength detector may be more sensitive (*depends on many variables and parameters which we have not discussed by in some cases a single wavelength detector could be several times more sensitive), but it often does not matter. What matters for HPLC method development is the ability to monitor many different UV/VIS wavelengths at once (a range) so you do not miss anything and can obtain accurate data. That is why a DAD is the choice for any type of HPLC method development work where the sample(s) have adequate chromophores. A single wavelength detector is always handicapped by a lack of selectivity. Selectivity is critical and far more important than sensitivity for most applications.

Regarding reliability, most any well maintained modern research grade detector could be considered reliable.

Dear Nafiu

Sensitive and reliable are different things. If you need the detector in a fixed set-up and routine analysis , I would prefer a UV-VIS wich is more stable and sensitive (detecting smaller amounts) depending on the type.

If you need it for multiple components or (if you do not have access to LC-MS/MS) for tox screening or similar, than I would prefer a diode array.

Please check a simiular question and its answers some years ago at https://www.researchgate.net/post/DAD-vs_UV-detector

Both are in fact UV/VIS detectors. Perhaps you are asking which is more sensitive, a single wavelength UV/VIS detector or a full scanning diode array detector (aka: DAD or PDA)?? A purpose built single-wavelength detector may be more sensitive (*depends on many variables and parameters which we have not discussed by in some cases a single wavelength detector could be several times more sensitive), but it often does not matter. What matters for HPLC method development is the ability to monitor many different UV/VIS wavelengths at once (a range) so you do not miss anything and can obtain accurate data. That is why a DAD is the choice for any type of HPLC method development work where the sample(s) have adequate chromophores. A single wavelength detector is always handicapped by a lack of selectivity. Selectivity is critical and far more important than sensitivity for most applications.

Regarding reliability, most any well maintained modern research grade detector could be considered reliable.

Dear Sir,

Di-iodo array detector is more sensitive one

Ahmed, what do you base that on? With similar flow cell path lengths, DAD by design is usually less sensitive.

Thanks Mr William and Mr Jos for the comprehensive answers