Most sensitive Agilent DAD

[Sniff]

Hey all,

Does anyone know how the sensitivity of Agilent's various DADs compare to each other? I remember that their "Max-Light Cartridge Cell" resulted in a significant improvement in sensitivity over their previous DADs but was curious if there have been any major improvements over the last decade.

I work at a small start-up and am shopping for the absolute best (most sensitive) used Agilent DAD available, but cost is definitely a factor. If I can find one that's substantially more sensitive but only costs $1000 more than the next best DAD, then I think I can make a case for buying the better one—but I would really need to show my boss some concrete numbers on just how much better it is.

I'm also open to purchasing another brand, as long as it plays well with Chemstation.

Thanks in advance for any recommendations you may have!

[Multidimensional]

It is not the specific detector that is adding increased sensitivity, it is the flow cell design. Their extra long path-length 60 mm cell has much higher sensitivity than the std cells (vs 10 mm path length). However, we have seen so many failures and fractures of these special Max-light flow cell cartridges that we do not recommend them. Instead, look for one of their DAD's that uses the conventional spring type flow cells (clothespin style). Those are bullet proof, reliable, no worries of breaking them as they are designed to open-up and release pressure when max'd out, then close back up. Great design.

If you want to add sensitivity to a DAD, then think about getting more advanced training in how to use the HPLC, optimize the flow path (e.g. flow cell selection, method improvements) and many of the advanced features in the DAD software (e.g. bandwidth) which can increase sensitivity.

"Proper Wavelength Selection for HPLC Method Development (or Purity Determination)"; https://hplctips.blogspot.com/2013/08/w ... ethod.html

"HPLC Flow Cell Volume & Path Length": https://hplctips.blogspot.com/2011/03/f ... ength.html

[S_G]

If you're on a budget and can't justify purchasing a $3000, 60 mm Max-Light cartridge, buy a G1315-series detector. The Max-Light with 10 mm cartridge gives similar sensitivity to the older style cells, but they plug too easily and aren't rebuildable in any form.

EDIT:

It is not the specific detector that is adding increased sensitivity, it is the flow cell design. Their extra long path-length 60 mm cell has much higher sensitivity than the std cells (vs 10 mm path length). However, we have seen so many failures and fractures of these special Max-light flow cell cartridges that we do not recommend them. Instead, look for one of their DAD's that uses the conventional spring type flow cells (clothespin style). Those are bullet proof, reliable, no worries of breaking them as they are designed to open-up and release pressure when max'd out, then close back up. Great design.

Glad it's not just me who's frustrated with these Max-Light cartridges!

[Sniff]

Oh wow, I had no idea those flow cells were so problematic. I loved the one I used to use and didn't have any problems with it, but that's n=1 datapoints, so not exactly a good sampling.

Thanks for the input!

[Jake]

As others have stated, yes, skip the max-light cells. They're not worth the trouble.

[Multidimensional]

We regularly provide consulting services to labs where the clients show us a draw filled with broken Max-Light cartridges (2, 3, 4...).

Also, if you also have broken ones and are looking for replacements, please be very cautious about buying used ones online at auctions sites such as ebay. That is where some of the broken ones end up being sold. The cells can not be rebuilt (designed to be disposed of) and the ones offered for sale are generally worthless at any price. Many times the broken ones are placed back in the box that the new one came in making it look like they are new. Some of the sellers even describe them as "new", because the outside of the cartridges looks nice and clean. Buyer beware. Save your money and either purchase a factory replacement cell from the manufacturer or buy a different detector which does not rely on that cell design. After you break one or two of those $3K + cells, you will be able to afford a very nice used DAD with std flow cell and not need replacement cells. That is our advice.