(^14) Upfront
The fight against fake pharma
continues: researchers
at Colorado State have
developed a straightforward
way to detect counterfeit
antibiotics – using a simple
color-changing paper test.
Researcher Charles Henry
tells us more
What was the inspiration behind the test?
For the last decade, I’ve been working
with other scientists in the developing
world, and have learned much about how
healthcare works – or doesn’t work – in
those countries. This piqued my interest
in developing low-cost tests that could
improve healthcare for people living
in those areas. At the same time, Kat
Boehle (1) and I were working on a test
for anti-microbial resistance. The test
detects bacteria by measuring an enzyme
(betalactamase) involved in antibiotic
resistance – using the bacteria’s own
resistance machinery against it. Kat
Don’t Have Your
Fake or Eat It
Marine Cotte works in the European
Synchrotron Radiation Facility,
Grenoble, France, where her job is to
support researchers in their scientific
endeavours. A colleague asked for
Cotte’s help to analyze some fragments
of a photograph produced by pioneer
of color photography, Louis Ducos
du Hauron.
“I first used infrared microscopy,
which allows you to scan two-
dimensional regions, define the pixel
size and then move from one pixel to
another, acquiring an infrared spectrum
at each pixel. In this way you can
ascertain the molecular composition,
as well as see where the molecules are
distributed,” Cotte says. “Synchrotron
infrared microscopy turned out to be
very efficient for the identification of
organic components, such as gelatine,
celluloid, resin, oil, and so on.”
Cotte also used X-ray microscopy to
work out the elements of composition,
and in particular, to identify the
pigments. “Ducos du Hauron’s books
showed he didn’t use the same pigment
at the beginning of his career as he did
later on,” she explains. “By identifying
the pigments, we could work out a kind
of ‘chronological marker’; for example,
we could identify Prussian Blue pigment
by the presence of iron.” The next step
was to identify the technique used for
printing, and for this they used X-ray
fluorescence spectroscopy to distinguish
different oxidation states. The presence
of chromium suggested carbon printing.
Despite his contribution to the
photography field, Ducos du Hauron
never enjoyed commercial success. “I
had not heard of him – barely anyone
had – until recently, but his work has
become important to me,” says Cotte.
“He was really passionate, spending
40 years constantly trying to improve,
not to make a profit, but simply to
develop a technique that anyone could
use.” Some museums are exploring the
idea of exhibitions to coincide with the
anniversary of his death, which, Cotte
hopes, will give Ducos du Hauron some
visibility. “Hopefully the museums –
and our scientific research – will finally
give him some of the recognition he
deserves,” she says.
Reference
- M Cotte et al., “Rediscovering Ducos du
Hauron’s color photography through a review
of his three-colour printing processes and
synchrotron microanalysis of his prints”,
Angew Chem Int Ed, 57, 1-6 (2018). DOI:
10.10 02 /anie.201712617.
Photos in Focus
Using synchrotron
spectroscopy to work out the
chemistry behind 200-year-
old photographs – and raise
the profile of a long-neglected
artist
Pioneering photographer Ducos du Hauron developed the general principle of three-color carbon printing (1).