The best prep column is one that performs the desired separation consistently, lasts a long time ( at least the duration of the research programme ), and matches the available budget.
In my limited experience, cyano columns fail the second criteria ( one Phenomenex, and one Varian prep column have died on me ). The column type I find most robust is a C18, and I would use a version of that phase, provided it achieves the first and third objectives.
Column brands. I've just counted my 119 active analytical columns. 44 are Phenomenex, and 41 are Waters. However, the age distribution is interesting, as I switched from rather expensive Waters and Agilent columns to Phenomenex columns ( often 30 - 50% of the cost ), about 5 years ago.
However, the C18 column I'm actually using for a sample today, is one of my original Phenomenex Luna columns, purchased in 1999. I'd hate to have to pull the logs for what has gone through that column over the past decade.
I've had columns fail prematurely from almost every major brand, was it the column, or was it me?. Who knows, but the reason Phenomenex has such a huge share ( 80+% ) of the NZ HPLC column market is that they have excellent technical support and will swap faulty column ( or offer discounts on replacements ).
Clearly NZ is an aberration in column markets, but the strong support and long lifetime of my Phenomenex columns is one reason why I have no hesitation in offering an alternative perception to Danko's.
Most people are aware that the original Phenomenex Gemini column was not as robust as it could have been, but my later NX version seems more durable ( ask me in a decade or so
. I'm sure most brands have lemons at some stage of their history.
This forum is lucky that it is graced by column specialists from several companies, and they all survive because they fill differing niches. People should look at their need and cost/benefit of the column, and purchase the product that matches it.
It's very likely that high cost columns will be more durable, and capable of working in more aggressive environments, but sometimes there are cheaper columns that will match your need and budget.
If your company, or client, is willing to pay for long-term durability, then you have greater choice, and can purchase columns that will give long service. But if budgets are tight, then don't be afraid to try cheaper brands, provided they offer the support ( including exchange / credit ) policy, and will match your analytical need.
If I, or my clients, could afford to purchase Waters/Agilent/? columns, I'm sure they would - but at NZ$20,000 for a prep column ( versus $6,500 for the alternative Phenomenex column ), I routinely trade cost versus immediate need.
I have six prep columns ( using 20 - 50mm diameter criterion ), and killed two cyano columns, and one Synergi Max-RP ( C12 ) before switching to more robust C18 columns. For prepaartive work, the amount of sample crud probably determines durability...
My experience is clearly different to Danko's, and when I have the choice ( column is not specified ), the local branch of Phenomenex are always my first port of call.
Mention of various brands is purely indicative, and doesn't indicate that they have given me a discount to promote their product - but they should, and all other brands should give me free samples of columns for long term real-life evaluation purposes
.
Please keep having fun,
Bruce Hamilton
PS. Before others point out the obvious, owning 120+ working columns, dating back to 1986, doesn't indicate greed ( he says hopefully
), or that additional columns would be unwelcome or unloved, because exploring new column technology is always fun.