Chemistry for cooks - the alliteration

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Chemistry for cooks - the alliteration

• Leo Gros, Noreen Klein, Sascha Klein
• Europa Fachhochschule Fresenius
• Abitur an der Rheingauschule 1970, 2006, 2005

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1. Chemists are observers

Szent-Györgyi (1925) - observation
patient brown skin (adrenalopathy) appl
e apple (just
cut) (brown) apple
apple (just cut) acids (brown)
polyphenoloxidase
citrus fruit juice
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Szent-Györgyi (1925) isolated an active substance

• It had been an acid, it seemed to be descended
  from an unknown sugar, that I called Ignose ,
  the substance itself I called Ignosinacid. But
  the editor of the newspaper, to whom I send my
  publications, didnt like any jokes and rejected
  the name. Godnose hadnt been anymore
  successful, therefore we agreed, the child ought
  to be called Hexuronacid. Later on, with advanced
  knowledge about the structure, it had to be
  renamed hastily and now it is called ascorbic
  acid (sometimes Vitamin-C-acid), since it is
  identical to Vitamin C and prevents scurvy.
  That's how I became a father without intending
  it, father of the Vitamin C.
• Therefore acid is good!

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Ascorbic acid prevents polyphenoloxidase
http//www.gartendatenbank.de/photo/2004012583
http//www.fao.org/ag/Ags/agsi/ENZYMEFINAL/Enzymat
ic20Browning.htmlASCORB
5

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To observe something means, to see
something, that has already been seen by
many, and to think something that nobody has
thought about before.

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2. Chemists know how to help themselves. A
strange salt in the soup.

www.schule-bw.de/unterricht/faecher/biologie/archi
v/tiere/voegel/Huhn2.jpg/view
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The revealing indicator

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This way chemists see red light

http//www.ieap.uni-kiel.de/plasma/ag-stroth/lehre
/physik/HTML/f40_08.html
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Based on this phenomenon, Bunsen and Kirchhoff
developed an analysis principle

http//lims.uni-duisburg.de/Lehre/Material/PMAll/v
orproben.pdf
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Today Atomic emission is used in quantitative
analysis

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3. Chemists have to remove dirt from the bathtub
like anyone else but they know where it comes
from

http//www.uni-essen.de/chemiedidaktik/SWM/Nachte
ileSeife/Wasserh.htm
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That's what surfactants look like
http//de.wikipedia.org/wiki/Tenside
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This is how chemists see calcium-surfactant
precipitates
-
Ca 2
-
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4. Chemists recognise the underlying
principles Three examples of effervescence
one principle

• NaHCO3 C6H8O7 ? NaC6H7O7 H2O CO2
• H3O HCO3- ? H2CO3 H2O ? CO2 2 H2O
• Brause (sherbet)
• Schorle (spritzer)
• Baking powder

http//de.wikipedia.org/wiki/Brausepulver
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5. Chemists know the tricksHow garlic destroys
poison(A story taking place at the Auer Dult
near Munich)

http//www.gartendatenbank.de/photo/2004012583
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Alliin                                      
Allylsulfensäure    alpha-Aminoacrylsäure
                                                  
                                             
Allylsulfensäure                       
                      Allicin

Alliin (()-(S)-Allyl-L-cysteinsulfoxid)  
                            
Thats only one part of the chemistry of garlic

http//www.uni-bayreuth.de/departments/ddchemie/um
at/knoblauch/knoblauch.htm1
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An example of a chemical reaction using
permanganate
(Determination of oxalic acid)

http//www.chemie.uni-greifswald.de/analytik/Lehr
e/SchrF6der/Quanti/WassergFCte.pdf
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Water pollution in the Elbe river at the
beginning of the 20th century.
http//www.springerlink.com/content/k85400x365p3q3
7h/fulltext.pdf
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Today in the labs its practiced like this

• Procedure
• The following determination is accomplished
  simultaneously with the water sample and
  distilled water
• Prepare in a 400 mL beaker boiling water for a
  water bath
• With a 25 mL pipette add of the water sample in a
  tall test tube and add 5 mL of a 2 mol sulphuric
  acid. Likewise 25 mL distilled water are mixed
  with 5 mL sulphuric acid. The test tubes are put
  in boiling water for ten minutes to adjust the
  temperature.
• Add exactly 5 mL potassium permanganate in both
  test tubes and leave them for exactly 10 minutes
  in the water bath. After ten minutes constant
  boiling add to each test tube 5 mL oxalic acid
• Afterwards the colourless, hot fluid with
  potassium permanganate is titrated until a light
  pink colouration persists for about 30 seconds

http//www.xlab-goettingen.de/pics/medien/1_109784
8861/Wasseruntersuchungen.pdf
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A recent publication tells us more
Here we show that human RBCs convert
garlic-derived organic polysulfides into hydrogen
sulfide (H2S), an endogenous cardioprotective
vascular cell signaling molecule. The
vasoactivity of garlic compounds is synchronous
with H2S production, and their potency to mediate
relaxation increases with H2S yield, strongly
supporting our hypothesis that H2S mediates the
vasoactivity of garlic. Gloria A. Benavides et
al., http//www.pnas.org/cgi/content/abstract/07
05710104v1

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Angew. Chem. 2009, S. 121, 163-166
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http//www.physics.ubc.ca/stm/news0229.pdf
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What does that teach us?

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How chemists see the world
they see molecules dancing where other people
see nothing

and our benefit
We understand our world better we can make
substances, transfer and measure them and we
learn about dangers and benefits of our actions