EDUARDO CESARMass spectrometer analyzes banknote: fast and simpleEDUARDO CESAR
In the last six months, criminal expert Adriano Otavio Maldaner, head of the chemical forensics lab at the Federal Police Department in Brasília, recalls that he resorted at least a dozen times to a sophisticated mass spectrometry technique created at the State University of Campinas (Unicamp). Maldaner resorted to this technique to clarify crucial doubts about the authenticity of the contents of manuscripts written in ballpoint pen; these documents were part of a lawsuit. In this kind of situation, the words written on a work permit or in a testament can be questioned if there is scientific proof that the handwriting on the documents underwent some kind of adulteration. Years after an original document was produced, a dishonest hand could have rounded out a number three to make it look like a number eight or added some lines that change the document’s meaning. Crude forgeries are easy to identify, but forgeries by professionals are a challenge even to the highly trained eyes of the experts. In the more complex cases, Maldaner resorted to Easi-MS (Easy Ambient Sonic-Spray Ionization Mass Spectrometry), a technique that does not destroy the sample being analyzed and can reveal, almost instantly, if more than one pen was used to write a document, if all the handwriting on the document is from the same period in time or if words were added later. “I’ve worked on cases for which I prepared an expert report based on the data I had obtained through this technique, and the judge asked me to explain how mass spectrometry works”, says Maldaner.
Easi, developed in 2006 by professor Marcos N. Eberlin, founder and coordinator of the ThoMSon Mass Spectrometry Laboratory at Unicamp’s Chemistry Institute, allows one to see the aging pattern of the chemical signature made by the ink from a pen. As time goes by, the dyes used in commercial ballpoint pens lose their CH3 methyl groups, with a constancy similar to that of a chemical clock. As a result, they reveal the approximate date on which the lines of a document were traced. “You can’t establish the exact date of the line, but we can make a clear distinction between young ink and old ink”, says Eberlin, whose projects are largely financed by a theme-related program run by FAPESP. This might not seem important, but an expert report that can demonstrate that the writing on a document dates back to the 1980s and not to the year 2000 can become a decisive factor in a lawsuit.
Easi provides other data on inks. Each commercial ballpoint pen brand produces a slightly different chemical signature. The method identifies these differences. “With Easi, we can examine overlapping layers of ink without damaging the paper and identify whether the layers came from different pens”, says Priscilla Lalli, a student enrolled in the doctoral program, who participated in the study. The analyses with the mass spectrometry technique were made on real documents of different ages, provided by the Federal Police, and on papers submitted to processes that simulate aging.
Basically, mass spectrometry, whose beginnings go back to more than one century of research, can be compared to a scale that can weigh molecules, provided they are in the form of ions, which are electrically charged particles. As the ions of two molecules with different compositions never have the same molecular weight or isotope profile, mass spectrometry can distinguish them. Easi is part of a new generation of techniques that have expanded the enormous scope of action of mass spectrometry, which nowadays can efficiently identify and quantify each molecule found in gases, liquids, and solids, and distinguish which atoms form these molecules and how they are organized.
The singularity of the mass spectrometry technique lies in how the electrically charged ions are generated from neutral molecules. This stage, called ionization, is crucial. In most cases, the molecules of the compounds have a neutral charge. To obtain ions, the traditional techniques apply electric fields, raise the temperature, or radiate a laser beam, for example, on the given material. The electrically charged particles release themselves from the sample and are then captured by the spectrometer. “Easi is much simpler and easier to use than the conventional techniques and only uses air under high pressure to obtain ions”, says Eberlin, as of last year the President of the International Mass Spectrometry Society (IMSS). “All we need is a mini compressor to generate them”.
THOMSON LABORATORYMark created with invisible ink and detail of counterfeit R$ (real) billTHOMSON LABORATORY
Sample of the real world
The researchers from Unicamp state that the Brazilian technique has two major advantages: it can be used under atmospheric pressure (no need for a vacuum) and under different environmental conditions (inside a laboratory or on site). Furthermore, the analyzed samples do not require any kind of prior treatment or preparation. All that needs to be done is to take the material to be analyzed, in its original state, and place it within reach of the spectrometer’s ionizing sonic spray . “The best treatment of the sample is no treatment, says Eberlin. The acronym Easi was intentionally chosen to name the method because it is similar to “easy”, so as to suggest that using this Brazilian technique is really very simple.
Scientific studies conducted with Easi have achieved major recognition in the scientific community. This year alone, Eberlin’s team wrote 11 articles on the different applications of this technique. Four of these were on the cover of international scientific journals: two were published as cover stories in Analyst, published by Great Britain’s Royal Society of Chemistry; one was the cover story in Analytical Chemistry, published by the American Chemical Society; and one was the cover story in Analytical and Bioanalytical Chemistry (a reviewed article published in the September issue). The first article in Analyst, published in April, was a study on inks and adulterations to documents. The second article in the same journal, published in October, was also a study on fraud, this time in partnership with the Federal Police: Easi efficiently distinguished counterfeit and genuine euro, dollar and real bills. In the case of the counterfeit bills, it was even possible to establish which kind of printer – ink or laser – had been used to print the counterfeit bills. To hinder criminal action, scientists suggest that marks in invisible ink – perceived only through mass spectrometers – be included on genuine bills.
Although the detection of fraud and of illegal acts raises a lot of interest (other studies focus on adulterations of medication, food products and illegal drugs such as cocaine and ecstasy), the researchers from Unicamp have also shown that the technique is equally useful to control the quality of chemical products. Using the method to analyze the elements found in different kinds of oil – a theme which was the topic of the cover story published in the May 15 issue of Analytical Chemistry – is one example. “We can also monitor the degradation of mineral and vegetable oils with Easi”, says chemist Rosana Alberici, a researcher at the ThoMSon lab. Scientists believe that the use of Easi can be a quick and inexpensive way to study the composition of biodiesel obtained from different sources and of ethanol as well. To this end, partnerships with Petrobras and with the National Metrology, Standardization, and Industrial Quality Institute (Inmetro) were established.
The technique was also tested to chemically characterize products from the Amazon Region. The research study, still in its initial stages, is now focusing on describing the oil from nuts. “The idea is to see how the compounds in the oil vary, depending on which area of the Amazon Region the nuts come from”, says biochemical engineer Mariko Funasaki, from the National Institute for Research on the Amazon Region (Inpa), who started working on a research project this year in partnership with colleagues from Unicamp. Preventing fraud in the sale of the oil – very often low quality components are mixed with the oil – is another objective of the partnership.
The Scotch that is not whisky
In addition to providing data for scientific studies and partnerships, the mass spectrometers of the ThoMSon lab provide services to monitoring and supervising entities. Some stories are interesting, and even amusing. In 2007, a collaborator of Inmetro in Rio de Janeiro got suspicious about a supposedly genuine Scotch being served at a party at the time of the Pan American Games. Without any qualms, he found a bottle of the Scotch and sent it to Campinas. The whisky was fake. “Very often, whisky is nothing but fermented sugar cane liquor with caramel”, says Eberlin. Nowadays, the color of the fake whisky – which stands like a trophy on a shelf in the lab – is so faded that the color itself advertises the fraud. However, three years ago, it was necessary to conduct a more complex and long analysis using the mass spectrometer to prove the fraud.
Six months ago, another curious case obliged the researchers to act as detectives. The civil police force from Americana, a city in São Paulo State some 40 kilometers away from the city of Campinas, came to Unicamp with samples of perfume made by a big, well-known Brazilian company. The police were suspicious that the perfumes were stolen goods. A truck loaded with the suspicious goods had been apprehended. However, everything seemed genuine: the packaging, the bottles, even the scent of the perfume. With Easi, the lab researchers compared the chemical signatures with the ingredients of the original fragrance. The final verdict was that everything was legitimate, except for the most important element: the perfume, which was fake.
When mass spectrometers become portable and less expensive, these analytical tools will become more widely accessible. “This is about to happen”, says Eberlin. “And when this day comes, simple, inexpensive techniques such as Easi will provide results in real time anywhere and will become efficient anti-fraud techniques”.
The project
Development and study of functional and structural materials within the perspective of complexity (nº 2003/09931-5); Type Thematic Project; Coordinator Marcos N. Eberlin – IQ-Unicamp; Investment R$ 450,974.73 and US$130,176.40 (FAPESP)
Scientific articles
EBERLIN, L. S. et al. Instantaneous chemical profiles of banknotes by ambient mass spectrometry. Analyst. v. 135 (10), p. 2.533-39. Oct. 2010.
LALLI, P. M. et al. Fingerprinting and aging of ink by easy ambient sonic-spray ionization mass spectrometry. Analyst. v. 135 (4), p. 745-50. Apr. 2010.
