Information Exchange

For those analytical chemists that are new to the field, you can use this area to ask questions on anything concerning HTCO techniques for analyses of DOM in natural waters.  Likewise, analysts that are more experienced can contribute to help answer these questions. 

Please post queries and replies via email to gsp@wpo.nerc.ac.uk or see Posting Your Comments for fax and "snail mail". It is important that the whole community can read and comment on the queries AND your answers!

MORE QUESTIONS AND ANSWERS

(09/10/01)

Recent... 

1.  Giovanni Daneri, CEA, Univ. del Mar, Chile asks: "How long do I have to condition a new oxidation column?"

I have a Shimadzu TOC-5000 which gives us non-stop headaches (read more below about the problem-prone Shimadzu ASI-5000). Still we keep at it... What is your experience with new oxidation columns ???. Usually we run MilliQ water for a couple of weeks before we get acceptable low blank values.

All the best,
Giovanni Daneri, gdaneri@udelmar.cl

ANSWER

2.  Prof. Dr. Arne Koertzinger, IFM, Kiel, Germany: MQ Scientific DOC Analyzer MQ-2000 (30/09/01)

Dear DOC experts:

Is there anyone out there who has experience with the new MQ Scientific DOC Analyzer MQ-2000? The descripton (poster at the American Geophysical Union/ASLO 2000 Ocean Sciences Meeting in San Antonio, TX) sounds good.
According to that, the system is well suited for field applications and also eliminates some of the problems reported for other HTCO machines.

It would be very interesting to hear about first lab (and perhaps field) experience with this new system and I would be grateful to get some feedback.

Arne Koertzinger, akoertzinger@ifm.uni-kiel.de

3.  Kathy Krogslund, Univ. of WA, USA : Potassium sulfate extract samples (23/08/01)

Hi folks!  Just got a request from a potential customer asking me to do DOC analysis on samples that are 0.5M potassium sulfate extracts.  Has anyone done samples like these using a Shimadzu TOC 5000 instrument?  I've had great success with samples lately and sure don't want to gum up the works, but there is a fair amount of business involved...and a graduate student who sounds almost desperate (but then that is the norm in my experience).

Any comments would be useful.  Thanks!  

Kathy, kkrog@u.washington.edu

4.  Sophie Le Roux, Antarctic CRC, Hobart, Tasmania: Spare autosampler!!! (23/08/01)

The Shimadzu ASI-5000 autosampler that runs with our DOC analyser has not been working properly for years. The 'Arm Horiz Arm Pulse Count' error keeps coming up and it's impossible to analyse more than four samples ! A lot of people have wasted time trying to fix it; it was even sent back to Shimadzu without any success (Surprised?  You shouldn' t be). With the CLIVAR cruise coming up in October I urgently need to find another solution or I'll have to do all the analyses manually, which is a pain as you know.

I'm now looking for a spare second hand ASI-5000 that we could buy or borrow for the cruise.
I'm also interested in any similar problem anyone has encountered with the ASI-5000, and  if they managed to fix it.

Many thanks for that.