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Na contents measure using Atomic absorption spectrometry
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Marvin
science forum Guru Wannabe


Joined: 24 Mar 2005
Posts: 224

PostPosted: Thu Mar 24, 2005 8:30 pm    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

bg wrote:
Quote:
I am using atomic absorption spectrometry to measure Na contents in
arabidopsis. I am using spectra AA 220FS of varian. and I am using K/Na
lamp. strange thing is K contents measure is oK no problem but when I
try the Na contents measure, standard value and standard curve is made
nicely but measure the sample the absolute value is not exact. when I
check the Na contents using standard the absolute value is usually
higher than real value. I feel relative value is O.K but absolute value
is different.

Can Someone help me.

Do a background correction. A flame containg sodium generates a strong continuum background that

can mess up youra analyses if a correction is not made.
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Farooq W
science forum Guru Wannabe


Joined: 25 Mar 2005
Posts: 240

PostPosted: Thu Mar 24, 2005 8:30 pm    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

bg wrote:
Quote:
I am using atomic absorption spectrometry to measure Na contents in
arabidopsis. I am using spectra AA 220FS of varian. and I am using
K/Na
lamp. strange thing is K contents measure is oK no problem but when I
try the Na contents measure, standard value and standard curve is
made
nicely but measure the sample the absolute value is not exact. when I
check the Na contents using standard the absolute value is usually
higher than real value. I feel relative value is O.K but absolute
value
is different.

Can Someone help me.

Most likely this is ionization interference since your results are
higher than the real value. The following might be a possible
explanation of your observation if your sodium standards do not contain
potassium at all. As you know AA technique is based on absorption of
light by the population of ground state neutral atoms, note the
equilibria involved when you run the samples, since K is easily ionized
than sodium, you have (i) K <----> K(+) + e, therefore the flame
being an electron rich environment reduces most of sodium ions, if
created in the flame at high temperature, to neutral sodium atoms by
(ii) Na(+) + e <------> Na, the equilibrium remains shifted to the
right from the ionization of potassium. This artificially increases the
population of ground state neutral sodium atoms resulting in higher
absorbance and thus concentration.
Please note that this is merely a speculation.
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Farooq W
science forum Guru Wannabe


Joined: 25 Mar 2005
Posts: 240

PostPosted: Thu Mar 24, 2005 8:30 pm    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

bg wrote:
Quote:
Farooq W wrote:
bg wrote:
I am using atomic absorption spectrometry to measure Na contents
in
arabidopsis. I am using spectra AA 220FS of varian. and I am
using
K/Na
lamp. strange thing is K contents measure is oK no problem but
when
I
try the Na contents measure, standard value and standard curve is
made
nicely but measure the sample the absolute value is not exact.
when
I
check the Na contents using standard the absolute value is
usually
higher than real value. I feel relative value is O.K but absolute
value
is different.

Can Someone help me.

Most likely this is ionization interference since your results are
higher than the real value. The following might be a possible
explanation of your observation if your sodium standards do not
contain
potassium at all. As you know AA technique is based on absorption
of
light by the population of ground state neutral atoms, note the
equilibria involved when you run the samples, since K is easily
ionized
than sodium, you have (i) K <----> K(+) + e, therefore the flame
being an electron rich environment reduces most of sodium ions, if
created in the flame at high temperature, to neutral sodium atoms
by
(ii) Na(+) + e <------> Na, the equilibrium remains shifted to the
right from the ionization of potassium. This artificially increases
the
population of ground state neutral sodium atoms resulting in higher
absorbance and thus concentration.
Please note that this is merely a speculation.

Thank you very much for your kind reply.

Both of My standard and sample have highly concentrated K+.
Have you experience measure Na contents in plant or other sample.
Can you show me your protocol?

Never had an experience of determining sodium by AAS (my experience is
too short). Do you have the cookbook of AAS provided by your instrument
manufacturer? What do they suggest for analyzing sodium? Could glass be
contributing to sodium contamination?

> thank you very much
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bg
science forum beginner


Joined: 24 Mar 2005
Posts: 10

PostPosted: Thu Mar 24, 2005 8:30 pm    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

Farooq W wrote:
Quote:
bg wrote:
I am using atomic absorption spectrometry to measure Na contents in
arabidopsis. I am using spectra AA 220FS of varian. and I am using
K/Na
lamp. strange thing is K contents measure is oK no problem but when
I
try the Na contents measure, standard value and standard curve is
made
nicely but measure the sample the absolute value is not exact. when
I
check the Na contents using standard the absolute value is usually
higher than real value. I feel relative value is O.K but absolute
value
is different.

Can Someone help me.

Most likely this is ionization interference since your results are
higher than the real value. The following might be a possible
explanation of your observation if your sodium standards do not
contain
potassium at all. As you know AA technique is based on absorption of
light by the population of ground state neutral atoms, note the
equilibria involved when you run the samples, since K is easily
ionized
than sodium, you have (i) K <----> K(+) + e, therefore the flame
being an electron rich environment reduces most of sodium ions, if
created in the flame at high temperature, to neutral sodium atoms by
(ii) Na(+) + e <------> Na, the equilibrium remains shifted to the
right from the ionization of potassium. This artificially increases
the
population of ground state neutral sodium atoms resulting in higher
absorbance and thus concentration.
Please note that this is merely a speculation.

Thank you very much for your kind reply.

Both of My standard and sample have highly concentrated K+.
Have you experience measure Na contents in plant or other sample.
Can you show me your protocol?
thank you very much
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Farooq W
science forum Guru Wannabe


Joined: 25 Mar 2005
Posts: 240

PostPosted: Fri Mar 25, 2005 4:01 am    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

Marvin wrote:
Quote:
Farooq W wrote:
Marvin wrote:
Do a background correction. A flame containg sodium generates a

strong continuum background that

can mess up your analyses if a correction is not made.


Is there something special with flames containing sodium? Don't
these
modern instruments auto-correct the background?


Do they do it automatically, or do they just have the capability to
do it when implemented?


Take Perkin Elmer's 2380 AAS for example, its about 10-15 year old
model, everything is manual. There is a knob for BG correction in
different modes eg AA mode (etc) by deuterium lamp, but no option for
"No BG correction" or turning off background correction, so I guess
absorbance measurements are autocorrected.

Quote:

Alkali metal atoms are easily ionized, so the electron number density
in the flame gets large.
Electron-ion recombination causes a continuum background emission.
How that affects an AA
measurement depends on the details of the instrument design and
setup.

Another person suggested that it is better to measure alkali elements
by flame emission than by AA.
Winefordner showed that years ago, but the makers of AA gear seem
to have convinced many that AA
is always better.

Is this same Winefordner who wrote "Spectrochemical methods of
analysis". Never had a chance to see this book but it is mentioned
everywhere, its not available in the library.

Quote:
Flame emission with background correction is definitely the way to go
for Na and K.


Also, it gives a pleasure to read your name in different references for
your chapter M. Marghoses et.al "Emission Spectroscopy", in Kolthoff's
treatise. Can this be had from somewhere?
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Marvin
science forum Guru Wannabe


Joined: 24 Mar 2005
Posts: 224

PostPosted: Fri Mar 25, 2005 5:55 pm    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

Farooq W wrote:
Quote:
Marvin wrote:

Farooq W wrote:

Marvin wrote:

Do a background correction. A flame containg sodium generates a

strong continuum background that


can mess up your analyses if a correction is not made.


Is there something special with flames containing sodium? Don't

these

modern instruments auto-correct the background?



Do they do it automatically, or do they just have the capability to

do it when implemented?

Take Perkin Elmer's 2380 AAS for example, its about 10-15 year old
model, everything is manual. There is a knob for BG correction in
different modes eg AA mode (etc) by deuterium lamp, but no option for
"No BG correction" or turning off background correction, so I guess
absorbance measurements are autocorrected.


Alkali metal atoms are easily ionized, so the electron number density

in the flame gets large.

Electron-ion recombination causes a continuum background emission.

How that affects an AA

measurement depends on the details of the instrument design and

setup.

Another person suggested that it is better to measure alkali elements

by flame emission than by AA.

Winefordner showed that years ago, but the makers of AA gear seem

to have convinced many that AA

is always better.


Is this same Winefordner who wrote "Spectrochemical methods of
analysis". Never had a chance to see this book but it is mentioned
everywhere, its not available in the library.

It Is Jim Winefordner from the Chemistry Department of the University of Florida. I don't know
about the book.

Quote:


Flame emission with background correction is definitely the way to go

for Na and K.

Also, it gives a pleasure to read your name in different references for
your chapter M. Marghoses et.al "Emission Spectroscopy", in Kolthoff's
treatise. Can this be had from somewhere?

It is long out of print, though you might be able to find a used copy somewhere. It was published
40 years ago, so it doesn't have anything about all of the advances since then.
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Dr_Dickie
science forum beginner


Joined: 03 May 2005
Posts: 16

PostPosted: Wed Mar 30, 2005 1:57 pm    Post subject: Re: Na contents measure using Atomic absorption spectrometry Reply with quote

"Marvin" <physchem@cloud9.net> wrote in message
news:1148nliiga88mb0@corp.supernews.com...
Quote:
Farooq W wrote:
Marvin wrote:

Snip

Winefordner showed that years ago, but the makers of AA gear seem

to have convinced many that AA

is always better.


Is this same Winefordner who wrote "Spectrochemical methods of
analysis". Never had a chance to see this book but it is mentioned
everywhere, its not available in the library.

It Is Jim Winefordner from the Chemistry Department of the University of
Florida. I don't know
about the book.



Good old Doc. The saying at UF is that God created light, and Jim started
looking into it the next day.
They say he will retire, but no one really believes that.

Sorry to say I never took his spec class (just didn't roll around at the
right time).
Go Gators
--
Dr. Dickie
Skepticult member in good standing #394-00596-438
Poking kooks with a pointy stick.
"The most exciting phrase to hear in science, the one that heralds new
discoveries,
is not 'Eureka!' ('I found it!'), but rather 'hmm....that's funny...'"
- Isaac Asimov
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Marc Brutschy
science forum beginner


Joined: 31 Mar 2005
Posts: 3

PostPosted: Thu Mar 31, 2005 12:05 am    Post subject: Re: calcium titration Reply with quote

bigtwinhog@hotmail.com (jhp45auto) wrote:

Quote:
Does anyone have any tips for conducting the EDTA calcium trtimetric
method, specifically on ground meat? This seems a simple process, but
we have encountered several problems, primarially with the reagents
themselves.

I would also worry about interference from any Fe in the meat. EDTA
chelates Fe as well as Ca.

Marc Brutschy
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Marc Brutschy
science forum beginner


Joined: 31 Mar 2005
Posts: 3

PostPosted: Thu Mar 31, 2005 12:36 am    Post subject: Re: Is it possible to regen Ferric Chloride at home? Reply with quote

On 4 Feb 2004 10:26:31 -0800, kasterborus@yahoo.com (Steve H) wrote:

Quote:
I'm currently etching brass using Ferric Chloride solution purchased
from Radio Shack. Obviously after a while the reaction slows down and
I have to replenish the etchant.

Currently I am disposing the spent ferric chloride by first
neutralizing the acidity with baking soda and then flushing down the
toilet.

(Can anyone confirm if this is a good/bad/ugly disposal method?)

Neutralizing the waste is a good idea, but as the other poster pointed
out, you are also flushing salts of copper and zinc. I doubt this is
much of a problem, though, given the small amounts and the likelihood
that these metals will be readily pulled out by your local wastewater
treatment facility.

Quote:
I have read many web pages that describe ways to regenerate the Ferric
Chloride using an oxidant - Hydrogen Peroxide has been mentioned more
than once. (Someone also suggested bubbling air through the solution
to slowly regenerate it)

Can anyone describe (quantatively) an "at home" way of regenerating
Ferric Chloride? I don't quite understand what happens to the
dissolved Copper salts - surely if they get converted back to Copper,
then the etching reaction will kick in again...?

I have about a 50% chemistry knowledge, so talk of anions, cations, et
al is OK, anything more and you might lose me...

Here is what is going on. Ferric chloride, FeCl3, is able to
"hydrolyze" water, which means that it can split it into H+ and OH-
ions. The OH- ions react with the ferric ions, Fe+3, over a period
of an hour or so to form insoluble ferric hydroxide, FeO(OH). That
leaves H+ and Cl- which, when you think about it, is a solution of
hydrochloric acid. That's what is doing the etching of the brass.

(You could actually just etch your brass with dilute hydrochloric
acid, but Radio Shack doesn't sell it. It's available in other
places, though.)

Brass is an alloy of copper and zinc. The HCl attacks the two metals,
dissolving them. Now, in solution, you have copper chloride and zinc
chloride salts.

Adding hydrogen peroxide or bubbling air through a dispersion of
ferric hydroxide won't do much of anything to ferric hydroxide.

The only way to "regenerate" your ferric chloride would be to collect
the insoluble ferric hydroxide (washing away the copper and zinc
salts) and then adding hydrochloric acid to dissolve it. You could
then evaporate the water and be left with ferric chloride again, but
this might be more expensive and time consuming than just buying more
ferric chloride.

Hope this helps.

Marc Brutschy
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Marc Brutschy
science forum beginner


Joined: 31 Mar 2005
Posts: 3

PostPosted: Thu Mar 31, 2005 1:01 am    Post subject: Re: Ammonia+Bleach ---> What? Reply with quote

"donald j haarmann" <donald-haarmann@worldnet.att.net> wrote:

Quote:
"the vast amount of chlorine given off by reaction of Clorox (about a 51% solution of
sodium hypochlorite)

I suspect you dropped a decimal point here. The original regular
strength Clorox bleach was about 5.2% NaOCl. The current Ultra bleach
is made at about 7.2% NaOCl.

Marc Brutschy
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Poster1
science forum beginner


Joined: 31 Mar 2005
Posts: 4

PostPosted: Thu Mar 31, 2005 3:19 am    Post subject: Re: Prove Us Wrong About $HIT-madzu.... Reply with quote

Take this to a political channel!


Chris Gaylor wrote:

Quote:
Prove Us Wrong About s**t-madzu.... Get 20,000 Japanese Yen!

We pledge that all of our facts about Shimadzu are in order
....and we'll back that claim up with real $money$

Since the inception of this homepage back in January of 1997, we have
stated unequivocally that "the factual information on our homepage has
been researched and found to be authentic.... it speaks volumes!"
Simply put, we have never knowingly concocted any untruths/falsehoods
about Shimadzu, their deceptive business practices or their inferior
product offerings! Then in September 1998, a group of independent
medical reviewers representing a prestigious online search engine
concluded that the factual information on our "professionally oriented
website was 100% accurate." Hence, the Shimadzu Consumer Alerts
homepage at http://www.bigfoot.com/~shimadzu-sux now sports a "4 star
rating" award.

In spite of these declaration(s) and award(s), there are a few
belly-aching malcontents (eg. George Orwell, Bruce Sinclar, Jim) who
are still non-believers. (We can't make you see the light if you're
wearing blinders!) And let's not forget the brainwashed misfits who
labor at Shimadzu on a daily basis. In an effort to quell these
malcontents, dispel those misfits and open the eyes of the
non-believers, we initially agreed in January 1999 to put our money
where our mouth is by offering 10,000 Japanese yen to back up our
claims regarding the other side of Shimadzu! Now we've upped the ante
yet again.

If anyone supplies/forwards us any indisputable/incontrovertible
evidence by email which contradicts any of the factual information on
our website (opinions exempted), then we will pay the first
contributor reporting any such untruth/falsehood the equivalent of
20,000 Japanese yen in the form of a money order forwarded by snail
mail to your attention. (Unfortunately, Shimadzu has been unable to
make a similar offer by rebutting the facts on our homepage!) This
good-will offer is open to everyone (including all Shimadzu employees
worldwide). Please note that we will have final say whether any
presented evidence is indeed indisputable/incontrovertible.

n.b. Since January 2004 (1 U.S. dollar = ~110 Japanese yen), no one
has taken us up on our most generous offer.... the truth is very
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n.b. We have absolutely nothing to gain by fabricating or publishing
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(starting with your money) to gain by resorting to the flagrant,
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n.b. Let it be known that no Shimadzu official, figurehead or troll
has ever questioned and successfully challenged the veracity of the
information on this website at any time. The truth hurts.... just ask
the habitual prevaricators at Shimadzu!

Question: Will Shimadzu admit to the facts found on this homepage and
come clean or will they simply persist with their propaganda depicting
full-blown lies and denials?

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For more information about Shimadzu, call 1-800-LIARS

Do YOU want $HIT in YOUR laboratory?

http://shimadzu.wxs.org
http://shimadzu.home-page.org
http://shimadzu-sux.iscool.net
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Poster1
science forum beginner


Joined: 31 Mar 2005
Posts: 4

PostPosted: Thu Mar 31, 2005 3:20 am    Post subject: Re: Shimadzu to Renounce Pacifism Reply with quote

why are you posting this here. no relevance whatever.


Chris Gaylor wrote:

Quote:
Rising sun

Originally published October 21, 2004 (Baltimore Sun Editorial)

IN THE HEART of Tokyo, the 135-year-old Shinto shrine originally was
built to honor a "peaceful country." But in the 20th century, the
Yakusuni Shrine served as a focal point for the aggressive nationalism
that led to World War II in the Pacific and then as a memorial to the
2.4 million Japanese who died in that and other conflicts, including
14 war criminals. And nowadays, with Prime Minister Junichiro Koizumi
making annual pilgrimages to Yakusuni -- the first Japanese prime
minister to do so -- the shrine is a political flash point as
militarism resurges in long officially pacifist Japan.

There has been much more than toothless symbolism to Mr. Koizumi's
visits. Japan, with the world's second-largest economy and campaigning
for a permanent seat on the U.N. Security Council, is evolving rapidly
away from the U.S.-written pacifist pledge embedded in Article 9 of
its postwar constitution: "The Japanese people forever renounce war as
a sovereign right of the nation."

The first break in Japanese pacifism came more than a decade ago with
its participation in U.N. peacekeeping and relief missions, but the
big steps were when Japan lent naval logistical support to the U.S.
war in Afghanistan and sent noncombat troops to Iraq, deployments
inconceivable just a few years ago.

And this month, a national defense panel recommended that Japan loosen
its long-standing ban on arms exports and its restrictions on its
forces abroad, including allowing them to attack foreign missile bases
-- recommendations likely to be approved. For the first time, a
rewriting of Article 9's self-defense-only posture is under debate.
There's resistance, but some Japanese opinion polls suggest that a
majority of Japanese, particularly younger generations, favor that
revision.

The United States, looking to more Japanese assistance in the war on
terror and in providing regional security in Northeast Asia, is among
the leading pressures pushing Japan to forsake its pacifism. Greater
willingness to commit troops to battle is seen as a necessary
commitment to gain that coveted Security Council seat. More
immediately, the ending of Japan's 60-year-old reluctance to take up
arms is being fueled by rising Japanese fears of North Korean nuclear
missiles and of growing Chinese might infused with anti-Japanese
sentiments.

A remilitarized Japan may serve U.S. interests -- particularly in
countering North Korean and Chinese ambitions -- but it also could
dangerously accelerate an arms race in Northeast Asia that would not
be in the world's interest and that could easily turn into a nuclear
arms race. A forceful Japan would be a double-edged sword.

http://shimadzu.wxs.org
http://shimadzu.home-page.org
http://shimadzu-sux.iscool.net
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Bruce Sinclair
science forum Guru Wannabe


Joined: 08 May 2005
Posts: 174

PostPosted: Thu Mar 31, 2005 3:32 am    Post subject: Re: Prove Us Wrong About $HIT-madzu.... Reply with quote

In article <424B885B.533769CA@ai5.net>, Poster <poster@ai5.net> wrote:
Quote:
Take this to a political channel!

It's religion with this guy :)

Bruce


-------------------------------------
The power of accurate observation is commonly called cynicism by those who have not got it.
- George Bernard Shaw
Cynic, n: a blackguard whose faulty vision sees things as they are, not as they ought to be.
- Ambrose Bierce

Caution ===== followups may have been changed to relevant groups
(if there were any)
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Poster1
science forum beginner


Joined: 31 Mar 2005
Posts: 4

PostPosted: Thu Mar 31, 2005 3:38 am    Post subject: Re: Poop Reply with quote

abuse complaint filed -


Chris Gaylor wrote:

Quote:
kellyclarksontv@cs.com (KellyClarksonTV) wrote in message news:<20041111052832.08198.00000470@mb-m04.news.cs.com>...
An hour ago I filled the toilet up to the top. Judging from my weight before
and after pooping, there was about 12 pounds of poop. Has anyone had this kind
of amount of poop before? I like the feeling of a massive amount comming out at
once that I have to stuff myself every couple of days ... lol ...

Did you see any s**t-madzu equipment in your toilet... I HAVE!

And I'm sure you'll find some of it in YOUR toilet (if you look)!

http://shimadzu.wxs.org
http://shimadzu.home-page.org
http://shimadzu-sux.iscool.net
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Poster1
science forum beginner


Joined: 31 Mar 2005
Posts: 4

PostPosted: Thu Mar 31, 2005 3:43 am    Post subject: Re: Did Shimadzu Japs aid attack on Pearl Harbor??? Reply with quote

another Shiavo case....

Repeating Rifle wrote:

Quote:
Can an independent party tell me what all this posting is about in less than
1000 bytes? I am curious.

Bill
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