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- Posts: 1
- Joined: Wed Sep 14, 2005 1:54 pm
Any advice would be appreciated.
Rob
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Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.
The system was never intended to be used directly with impurity samples; it was designed for major-component type assays (potency, content uniformity, dissolution, etc.). The only way to use AMDS to effectively develop impurity methods is to work with spiked samples. This is no secret, one of the first few screens when you run the "Chromatography Manager" (the program that controls the method development process) says that it is not designed work with peaks of < 1% of the total area (in fact, it will ignore those small peaks).1) How does the AMDS auto integrate? Peaks that are baseline aberations should not be integrated. Integration by the human eye is far more accurate, especially for impurity runs!
The short answer is "no". AMDS is basically a selectivity-manipulation program. If you have tailing problems on a pilot run (usually a full-range gradient), those should be dealt with first, for the very good reason that the things we do to fix peak shape problems typically impact selectivity as well.2) Will it account for peak shape dificulties (on on-going problem for many chromatographers out there).
That's another easy answer" "yes". In fact the AMDS system uses DryLab. What it does, essentially, is to start with a set of user requirements and some basic information about sample chemistry. Based on that, it assembles a sequence of up to six proposed tG/T models (using different columns, organic solvents, and/or pH values) ordered by expected probability of success (as defined by the developers). It then runs the calibrations for each tG/T model in turn and evaluates the resolution map. If no conditions are found that meet the requirements, the program goes on to the next model. If suitable conditions are found, the program runs those conditions to confirm that they do, in fact work, and then exits.3) Does it incorporate temperature / tG time programming as per a manual DryLab approach.
Beyond making the general point that AMDS really doesn't address accuracy and precision (the focus is on selectivity and separation) I can't really comment on that since I haven't been officially involved in two years. I'd be really surprised to see papers on it, though, because it doesn't break any new chromatographic ground. What is does is automate a well-known, well-documented strategy.4) How have the chromatographic community taken to it... can't say I've seen many papers on it detailing its attributes such as precision, ease of use etc.
1) you can use AMDS in anther way: set the limits such critical that it won't find a suitable prediction (eg Resolution of 5 in less than 2 min).Rob,
As I see it though, some reservations:
1) How does the AMDS auto integrate? Peaks that are baseline aberations should not be integrated. Integration by the human eye is far more accurate, especially for impurity runs!
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4) How have the chromatographic community taken to it... can't say I've seen many papers on it detailing its attributes such as precision, ease of use etc.
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