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Tech News in Forensic Science and Identification Services

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For Forensic Scientist, I found the following news interesting. You are welcome to add reviews or news on the Forensic Science and related worlds.

Gel turns clear for cocaine detection by Lewis Brindley in Chemistry World 22 January 2010:

Chinese researchers have developed an aptamer cross-linked hydrogel that changes from bright red or blue to colourless when exposed to tiny amounts of cocaine. No sophisticated analysis is required, and it is hoped the gel will provide quick visual tests for small molecules such as drugs, explosives or water contaminants.
The gel is made from polymer chains that are weakly held together by aptamers: short peptide chains that are engineered to bind to specific molecules. In this case, the researchers, led by Weihong Tan at Hunan University and Chaoyong Yang at Xiamen University, used an aptamer that binds strongly to cocaine.

More at : www.rsc.org/chemistryworld/News/2010/January/22011002.asp
 

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The following is a bit technical but might be of interest for people in forensic science:

To catch a cheating athlete by Rajendrani Mukhopadhyay/Washington DC, US in Chemistry World, 08 February 2010

rsc.org/chemistryworld/News/2010/February/08021001.asp

As the athletes take centre stage at the Vancouver 2010 Winter Olympics and Paralympic Winter Games this month, chemists will be hard at work behind the scenes to catch athletes looking to win by taking drugs or blood products to artificially boost their performance during the competition.
Doping is as old as the games - the ancient Greeks ate special diets and potions to enhance their athletic prowess - but over time, the practice has become considerably more sophisticated. Sports authorities began introducing drug testing in the 1970s and today, a variety of techniques exist in specialised anti-doping laboratories to catch a myriad of performance-enhancing products.
The range of drugs that can potentially be abused is mind-boggling. Christiane Ayotte, a sports-doping expert at the National Institute of Scientific Research in Canada, is heading the doping control laboratory during the Vancouver games. She says that even if a drug is revealed by the authorities as being abused, it doesn't disappear from the roster of performance-enhancing substances. For example, Canadian sprinter Ben Johnson's spectacular downfall from sports glory in 1988 was triggered when stanozolol, an anabolic steroid, was found in his urine sample. But stanozolol continues to be detected today in some cheating athletes. 'There is a basic arsenal to which more and more substances are being added but no drug is disappearing, except perhaps the narcotics,' says Ayotte.
Along with the anabolic steroids, testosterone and erythropoietin (EPO) continue to be abused. They are 'the two mainstay drugs and have been for 30 years,' says Don Catlin, a pioneer in the world of anti-doping testing and a founder of the non-profit organisation, Anti-Doping Research. 'With EPO, you can deliver more oxygen to the cells and get better performance. That cuts across all fields of sports. Testosterone, being the main androgen for men and women, is a powerful drug, and if you can figure out a way to get it into [your] system and not trip the alarms, you can be a winner.'

Beating the cheats
Mass spectrometry (MS), in several forms, is the main workhorse in anti-doping laboratories. Samples are generally first screened to look for the tell-tale peaks in the spectra of most of the abused drugs.
'We still have some substances which are very well detected by traditional gas chromatography-mass spectrometry [GC-MS] but we're going more and more into liquid chromatography-tandem mass spectrometry [LC-MS/MS] which allows us to reach some very low levels of detection,' explains Olivier Rabin, science director of the World Anti-Doping Agency (Wada). 'Now you have a whole range of mass spectrometry devices that allow you to reach levels of sensitivity that were not even dreamed of five years ago.'
However, with the greater sensitivity of new instruments, comes some unexpected consequences. 'We now detect very minute traces of substances that we believe can be related to pure contamination and not active abuse,' says Rabin. 'Take cocaine, for example. We can reach levels of detection of cocaine that are so low that they could be related to unintentional exposure by someone just by touching a few notes of contaminated paper money and putting their fingers in their mouth.'
For EPO, the standard detection method is an isoelectric focusing test developed in 2000 by a team at the French National Anti-Doping Laboratory headed by Françoise Lasne.1 Synthetic and natural EPO differ in their glycosylation and carry different types of sugars in their chains. The differences in the sugar chains make synthetic and natural EPO migrate to different positions on a gel and produce different sets of bands.
But the method can only detect synthetic EPO if the athlete is tested within a few days of taking the drug and is 'extraordinarily difficult' says Catlin. 'It takes three days to do. You have to be exceedingly careful and meticulous. If everything goes well, the test works. But compare that to the ease of shooting a mixture into a mass spectrometer and seeing a spectrum. That's where the problems really lie with EPO.'
Because the detection of EPO by isoelectric focusing is so cumbersome and expensive, not all samples are tested for EPO, explains Ayotte. The cheaters hope not to get found out - 'it's always a cat-and-mouse game,' she says.

The battle
The cat-and-mouse description is indeed accurate. Because the stakes are so high in winning a high-profile competition, the sports authorities and the cheating athletes are locked in an ever-evolving battle: as investigators in the anti-doping laboratories develop better techniques to catch drugs, cheating athletes figure out ways to dodge detection. For this reason, Ayotte says 2000 athletes will be tested at the Vancouver Games, that's 30 per cent more testing than in the previous Winter Games.
The increased pressure on testing is occurring because authorities know that cheating athletes are taking more extreme measures, even during the off-season when they are not competing. 'We know from anecdotal evidence and reports that athletes dope around Christmas time in order to get the benefits during the competing season,' notes Ayotte.
An example is blood doping, where cheaters increase their haemoglobin count by taking drugs during the off-season. They withdraw the blood that's richer in haemoglobin and store it. Then, just before a competition, once the anti-doping inspector leaves with blood samples from the athletes for testing, the cheaters transfuse the stored blood back into their bodies and head out to compete.
Doping approaches like blood transfusions and ingesting human growth and peptide hormones are vexing for the anti-doping investigators. Distinguishing the naturally occurring substance in the body from that taken from a bottle is difficult. Testosterone is an exception because there is a carbon isotope ratio mass spectrometric analysis that catches the presence of the artificial version based on a skewed carbon-12:carbon-13 ratio. But with most other drugs based on molecules found naturally in the human body, the experts say developing accurate detection methods remains one of their biggest challenges.

Challenges on the horizon
Drugs in the pipeline always have the anti-doping experts on alert. For example, Hematide is an anaemia treatment being developed by Affymax currently in clinical trials in the US. 'The drug circulates in the bloodstream and finds the EPO receptors,' explains Catlin. 'It sits on them, turns them on, and acts almost like exogenous EPO.' Investigators are working on a detection method for the drug, but Catlin suspects some cheating athletes are already abusing it.
It's not just drugs. There are concerns about gene therapy, although experts say they don't have any evidence yet that athletes are toying around their own genetic material. Rabin explains that one of Wada's mandates is to anticipate the future of doping in sports and to be more efficient in the fight against it - gene doping is an element of this, he says.
Some research groups are exploring ways to spot genetic manipulations. For instance, Maria Minunni and her team at the Universityof Florence in Italy have developed an affinity-based biosensor to identify genes that are artificially inserted into a genome.2 The test is based on the hybridisation of DNA strands taken from a genetically-manipulated sample to single-stranded probes immobilised on a special surface of a quartz crystal microbalance. 'You can see the hybridisation in real time,' says Minunni. 'There is a shift in the signal, meaning the analyte is binding the surface. [The systems] don't require any labelling so they are user-friendly and have fast analysis time.'
With support from Wada, Minunni's team is now trying to convert the sensor from a quartz crystal microbalance system into one that is based on optical detection. 'An optical sensor allows us to detect many different targets so you can move into an array format,' she explains.
'The problem with this kind of analysis is you don't know what to look for,' says Minunni. 'In principle, you have to test for different markers because you really don't know which kind of promoter or gene has been inserted. You could get negative results because some genetically-modified athletes could use promoters that are not in the list of the ones being tested.' With an array format with multiple probes, the team could cast their net wide and catch as many possible foreign gene inserts as possible.

Far from over
The experts are proud of how far they have come in tackling doping in sports. 'If I look today at where we stand, I think a lot has been achieved,' says Rabin.
But in the same breath, he adds, 'a lot remains to be achieved. I think today one of our biggest challenges is to make sure we can create strong links with the drug agencies and the pharmaceutical and biotechnology companies so we have access to the drugs with doping potential sufficiently ahead of time to establish the detection methods.'
Rabin and the other anti-doping experts, well aware that some athletes are always looking to get ahead of them, are not ones to rest on their laurels. As Rabin says, 'the race is still on.'

References:
  1. F Lasne and J de Ceaurriz, Nature, 2000, 405, 635
  2. S Scarano et al, Anal Chem, 2009, 81
 

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Anthrax Case Closed by William G. Schulz, Chemical & Engineering News, February 23, 2010

Investigation: FBI concludes that government biodefense researcher Bruce Ivins was the culprit in the attacks

The FBI has closed its case on the infamous 2001 anthrax mailings, known as the Amerithrax investigation. Government biodefense researcher Bruce Ivins, who killed himself after being identified as a suspect, "was responsible for the death, sickness, and fear brought to our country by the 2001 anthrax mailings," said an FBI official in a statement released on Feb. 19.
The FBI's extensive, more than eight-year investigation included the development of pathbreaking technology to "fingerprint" the DNA of the anthrax spores used in the attacks. According to the FBI statement, that work "allowed investigators to pinpoint the origins of the anthrax. The FBI Laboratory, in conjunction with the best experts in the scientific community, developed four highly sensitive and specific tests to detect the unique qualities of the anthrax used in the 2001 attacks. This took several years to accomplish, but in early 2005, the groundbreaking research successfully identified where the anthrax used in the mailings had come from."
A National Academies panel is reviewing the science the FBI used to reach its conclusion in the case (C&EN, Aug. 17, 2009, page 34). The panel has said it will not produce an opinion on the guilt or innocence of anyone identified as a suspect by the FBI, but will restrict its work to an evaluation of the science.
A frequent critic of the FBI's investigation, Rep. Rush Holt (D-N.J.), blasted the FBI's conclusion. He called the investigation "close minded" and said the bureau's evidence would not stand up in court.
Because Ivins is dead and a court case is thus impossible, the FBI seems "satisfied with barely a circumstantial case," Holt said. "The National Academy of Sciences review of the FBI's scientific methods in this case won't be released until summer," he added, "but the FBI doesn't seem to care."

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2010 American Chemical Society
 

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CSI's Latest Clue—Bacteria, by Constance Holden, ScienceNow, on March 15, 2010: 

news.sciencemag.org/sciencenow/2010/03/csis-latest-clue--bacteria.html

Criminals already have to be careful not to leave fingerprints or DNA that could incriminate them. But they might want to carry hand sanitizer, too, according to a new study that suggests a new way to finger perpetrators from their skin bacteria.
The human body hosts hundreds of bacterial species that perform various salubrious housekeeping chores, from aiding digestion to helping the immune system identify foreign invaders. Every person—even an identical twin—has a unique distribution of bacteria on various body areas. Now some researchers are suggesting that these individual differences could lead to the development of new crime-solving tools.
Biologist Noah Fierer of the University of Colorado, Boulder, and colleagues have been mapping the composition of bacteria that inhabit various body sites. They and others have discovered that the human body actually comprises a couple dozen mini-ecosystems. Not only are there separate colonies inside and out, but skin harbors a multitude of bacterial colonies. Bacteria found on the smooth, dry forearm, for example, are as dissimilar from those in the moist, warm armpit as deserts are from rainforests, according to researchers at the National Institutes of Health.
What's more, these colonies vary from person to person, and they are stable over time. Because only 13% of bacterial colonies on the palm are shared between any two individuals, Fierer and colleagues wondered if bacteria from palms and fingertips could be put to forensic use.
To determine how similar a person's fingertip bacteria are to bacteria left on computer keys, the team took swabs from three computer keyboards and compared bacterial gene sequences with those from the fingertips of the keyboard owners. Today in the Proceedings of the National Academy of Sciences, they conclude that enough bacteria can be collected from even small surfaces such as computer keys to link them with the hand that laid them down.
The researchers then tested how well such a technique could distinguish the person who left the bacteria from the general population. They sampled bacteria from nine computer mice and from the nine mouse owners. They also collected information on bacterial communities from 270 hands that had never touched any of the mice. In all nine cases, the bacteria on the mice were far more similar to the mouse-owners' hands than to any of the 270 strange hands. The researchers also found that bacteria will persist on a computer key or mouse for up to 2 weeks after it has been handled.
Fierer says the characteristics of a person's bacterial colonies are so persistent that "if you wash your hands, it only takes a few hours for a community to reestablish itself." That's probably because the bacteria are living in deeper skin layers, he says. Fierer adds that it may be possible to retrieve useful amounts of bacterial gene sequences from textured surfaces that won't yield fingerprints.
Geneticist Elizabeth Grice of the National Human Genome Research Institute in Bethesda, Maryland, cautions that "it is difficult to determine at this point how unique a person's skin microbiota is because so few people's skin microbiomes have been fully characterized."
The team agrees that their research is preliminary and that the method needs to be tested on other surfaces. But Fierer points out that it took 50 years to figure out the nuances of standard fingerprinting. "The idea is that we leave this trail of bacteria behind us, and that trail may be informative."
 

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For CSI fans:

Specials: Science in court, Naturenews, 18 March 2010

www.nature.com/news/specials/scienceincourt/index.html

Forensic science evolved less as a conventional academic discipline and more as a service driven by the needs of law enforcement. As a result, the vast majority of its day-to-day tools — from fingerprint analysis to hair- and fibre-matching — have developed without the influence and scrutiny of conventional academic research. In this special, Nature examines the gap between academia and the forensic lab, and explores ways in which the two areas can come together to put science in court on a stronger footing.

Table of content:
    * Editorial
    * Features
    * Opinion
    * Audio & Video
    * Elsewhere in Nature
 

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Sophie Rovner, A Shield Against Ricin, Chemical & Engineering News April 16, 2010

Drug Development: Small molecule defeats potential bioterrorism agent

A whole-cell, high-throughput screen of thousands of small molecules has turned up a compound that protects mice from what would normally be a lethal dose of inhaled ricin, according to molecular biologist Daniel Gillet of the Alternative Energies & Atomic Energy Commission, in Gif sur Yvette, France, and cell biologist Ludger Johannes of the Curie Institute, in Paris (Cell  2010, 141, 231).
A large amount of ricin—one of the most toxic chemicals around—is produced as waste during the extraction of oil from castor beans. Already notorious for its use in the assassination of a Bulgarian defector in London during the Cold War, ricin could be dispersed as an aerosol in a bioterrorist attack, notes Vern L. Schramm, a biochemist at Albert Einstein College of Medicine of Yeshiva University, in New York City. Schramm’s own ricin work includes the development of a rapid assay that detects the toxin (Anal. Chem. 2009, 81, 2847).
No proven antidote is available at present. But the compound identified by the French researchers, a tricyclic imine called Retro-2, could be a promising lead for an anti-ricin drug, Schramm says.
Retro-2 works only if injected prior to ricin exposure. Gillet and Johannes are now trying to adapt the compound so it can be administered after exposure to the toxin.
The researchers are also trying to identify Retro-2’s molecular target. They have already determined that the compound blocks transport of ricin within a cell into the cytosol, preventing ricin from disrupting ribosomes that produce proteins needed for the cell to function.
Retro-2 might also offer protection against other toxins that operate via this same route, including Shiga-like toxins produced during infections by enterohemorrhagic Escherichia coli strains, which can cause kidney dysfunction and death. However, testing this hypothesis in mice is proving difficult as a result of regulations on the distribution of toxins. “We have been trying to purchase Shiga toxin 2 to perform our studies for over six months,” Gillet and Johannes note in an e-mail. They hope to obtain the material this year.

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2010 American Chemical Society
 

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More on Ricin, they claim that the drug design needs to be improved, so you know what to do on your free time !

Lewis Brindley, Ricin antidote on the horizon, Chemistry World, 23 April 2010

www.rsc.org/chemistryworld/News/2010/April/23041001.asp

For the first time, compounds that protect against ricin poisoning have been identified by French researchers. It's hoped the research could lead to an antidote for the poison, which is a thousand times more toxic than cyanide.

Banned under chemical weapons conventions, ricin became infamous when a modified umbrella-gun containing a poisoned pellet was used to kill Bulgarian dissident Georgi Markov in 1978. Although not as potent as synthetic nerve agents, ricin is obtained from a natural source - the castor bean - so could potentially be more easily obtained by terrorist groups.

Research has been undertaken into an antibody-based vaccine and antidote at the Defence Science and Technology Laboratory in Porton Down, Wiltshire, UK, but they are not yet widely available.

There is currently no antidote for ricin intoxication,' says Daniel Gillet, who led the project at the biological research division of the French Atomic Energy and Alternative Energies Commission (CEA). In collaboration with Ludger Johannes at the Curie Institute in Paris, the team screened 16,480 different compounds to search for any that offered protection. Of these, two were found to protect mice from being killed by a lethal dose of ricin - and were surprisingly low in toxicity themselves.

Ricin causes harm by cleaving important bonds in RNA ribosomes - cellular factories that produce proteins from amino acids. Without proteins being produced, the cells die. The two new compounds - named Retro-1 and Retro-2 - are thought to offer protection by blocking the route through the cell that ricin uses to reach the ribosome. 

However, the activity and potency of these two compounds needs to optimised, Gillet told Chemistry World. 'At the moment, if we were to treat a human we would need a very big pill,' he says.

'This work opens a route for developing pharmaceuticals that could be used in a prophylactic way to prevent ricin poisoning, but also develop antidotes to treat after poisoning,' says Alastair Hay, a toxicologist at the University of Leeds, UK.

Retro-1 and Retro-2 may also find roles in fighting virulent bacterial toxins (called Shiga toxins) that attack cells with a similar mechanism, Hay adds. 'Significantly, the effectiveness of these two compounds might treat other toxin-related illnesses such as that caused by cholera or E.coli  because their toxins follow a similar route to the ribosome,' he says.
 

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Learned something today about "legal" herbal blends that gets you High. The following news  is a bit specialize but Analytical Chemist working in Forensic Lab might find it of interest.

www.rsc.org/Publishing/ChemScience/Volume/2010/06/spicing_up_drug.asp

Amaya Camara-Campos, Spicing up drug screening , Highlights in Chemical Science, 13 May 2010:

A method for quick identification of potential illegal components in commercial herbal products has been developed by UK scientists.
Some commercial herbal blends containing non-traditional cannabinoids attract attention as legal products with similar effects to cannabis. One such product, Spice, has been found to contain the synthetic compound JWH-018, a cannabinoid receptor agonist from the aminoalkylindole family. Until they were banned recently, the popularity of these herbal products had dramatically increased and they came to be known as 'legal highs'.
At the Manchester Metropolitan University, Craig Banks and his colleagues analysed the Spice product Gold Spirit using standard gas chromatography-mass spectrometry (GC-MS) techniques confirming the presence of JWH-018 in its composition. But given that the manufacturers can readily change the components of Spice, an easier method to identify the presence of prohibited compounds in these complex mixtures would be highly welcome, explains Banks.
GC-MS requires liquid extraction of the sample before analysis so Banks went on to develop a screening process using solid probe MS, which does not require sample extraction. Taking a solid probe mass spectrum of the spice product and subtracting the GC mass spectra of alpha-tocopherol, the main component in Spice products, allows the minor fragmentation patterns to be clearly visible and quantifiable.
'We demonstrate that the sample can be used as received or found on a person and put into a solid probe MS which proves, without any doubt, the presence or absence of banned components,' says Banks. 'I see this method being taken up in labs worldwide as a screening tool and can likely be extended to other herbal highs,' he says.
Cristina Davis, an expert in analytical sensors from the University of California, Davis, US, agrees that 'this is a very valuable new screening tool for law enforcement and forensic investigations.' For Davis, one of the critical points of the research is the possibility of easily adapting the method to emerging prohibited compounds. 'Their test provides a new surveillance route for rapidly changing combinations of synthetic narcotics that may be manufactured and doped into commercial products,' she concludes.
'We have only seen the tip of the iceberg in terms of legal highs, for example methadrone has recently been banned but already there are alternatives out there to quickly replace it,' Banks adds.
 

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Hilary Burch, Fighting forgery from inside, Highlights in Chemical Technology, 19 May 2010:

rsc.org/Publishing/ChemTech/Volume/2010/07/fighting_forgery.asp

US scientists are using a reaction between two sheets of chemically treated paper to create patterns that could deter counterfeiters.
In traditional anti-forgery methods, the surfaces of official documents and currency are patterned using deterrents such as holograms and microprinting. But these methods are often easy to mimic or forge. Now George Whitesides and colleagues at Harvard University, US have devised a way to pattern paper from within its pores using a simple precipitation reaction.
One sheet of paper is printed with a barrier of wax or toner in a predetermined two-dimensional design and acts as a stamp, explains Whitesides. The stamp is then 'inked' with a salt solution of copper nitrate and pressed into a second sheet which has been soaked in a solution of sodium hydroxide. As the sheets come together the reagents mix, forming a cyan-coloured solid (copper hydroxide) which is trapped within the pores of the second sheet in the same two-dimensional pattern. The paramagnetic nature of the solid means it can also be manipulated with a magnet.
The combination of patterned paper and local chemistry is very easy to implement, and can make structures that would be difficult to make otherwise,' comments Whitesides. The technique can also be used to store enzymes and other catalysts within the pores of paper for simple detection and diagnostics applications.
Emanuel Carrilho an expert in forensic analysis from the University of Sao Paulo, Brazil, is interested in this unusual and creative method saying it is 'simple and uniquely selective' and a 'nice tool that opens up opportunities to add new function to paper and other porous substrates.'
Whitesides and colleagues are now looking into other ways in which chemistry might be used to generate unique signatures in materials.
 

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Emma Shiells , Explosive sensing, Highlights in Chemical Technology, 09 June 2010:

rsc.org/Publishing/ChemTech/Volume/2010/07/sensing_terrorism.asp

A fast, on-site sensor detecting peroxide-based explosives could help avert future acts of terrorism.
Peroxide-based explosives are popular amongst terrorists as the ingredients used to make them are readily available. The world has witnessed many tragedies as a result of terrorists using peroxide-based explosives, including the July 2005 London bombings that involve triacetone triperoxide (TATP).
Now Resat Apak and colleagues from Istanbul University, Turkey have designed a colorimetric sensor that can selectively detect the peroxide-based explosives TATP and hexamethylenetetramine (HMTD) and can be used on-site. Other spectroscopic methods for explosive detection employ acid or enzyme digestion of the peroxide explosives before fluorimetric detection of the by-product hydrogen peroxide is carried out. However, these methods are often time consuming and vulnerable to interference from other strong oxidising agents and need to be carried out in a laboratory.
In Apak's sensor, the sample is acid hydrolysed and passed over a Nafion membrane containing a copper-neocuproine complex that turns yellow in the presence of trace amounts of TATP or HMTD. The sensor would be ideal for post-blast analysis and identifying unknown materials or suspect packages confiscated by the police, says Apak. It is cheap to make, easy to use and suffers no interference from other contaminants, such as nitro-explosives (TNT) or washing detergents.
'The present technique can provide fast on-site inspection of TATP and HMTD explosives, which can be beneficial for giving quick-response against terrorist actions,' comments Nadir Serin, chief research engineer at the Scientific and Technical Research Council of Turkey.
In future, a hand-held version of this device could see this sensor being used to check surfaces or airborne samples in airports, government buildings and other places at risk of being targeted by terrorists, says Apak. 'Since TATP is essentially a kind of explosive used in terrorist attacks it is expected to be used by police criminological laboratories for on-site screening purposes where fast decision-making is of critical importance,' he adds.
 

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I use routinely MS(ESI) and we do have access to a wide range of MS machines. I am aware on the MS analytical power but I was surprised when I read "The real banknotes show similar data (m/z ions), distributed evenly over the entire surface, despite age, denomination and colour pattern." in the Quote below.

http://rsc.org/Publishing/ChemScience/Volume/2010/07/revealing_fake_money.asp

Highlights in Chemical Science, Volume 2010, 07

Revealing fake money

02 July 2010

A simple and fast technique to examine the surface of banknotes and identify counterfeits has been developed by scientists in Brazil and the US.

The counterfeiting of banknotes is a global problem that is increasing in scale and sophistication. Counterfeiters now use computerised reproduction methods like scanners and laser printers to copy real notes, and gone are the days when a fake could be spotted by simply testing the look and feel of the paper.

The new technologies used by counterfeiters have thrown out a challenge to law enforcement. 'Forensic laboratories are therefore confronted with an increasing demand to analyse larger numbers of samples with faster responses and reliable verdicts for samples fabricated with greater sophistication than ever,' says Marcos Eberlin, one of the researchers at the University of Campinas, Brazil.

With Graham Cooks at Purdue University in West Lafayette, US, Eberlin and colleagues have devised a mass spectrometric technique that can give a chemical profile of banknotes in seconds. There is almost no sample preparation required, it is non-destructive, and the test can also reveal which counterfeit method was used to create the 'funny money'.

This new technique relies on using desorption ionisation mass spectrometry to test different spots on the banknote. The real banknotes show similar data (m/z ions), distributed evenly over the entire surface, despite age, denomination and colour pattern. This provides a fingerprint for the real banknotes. When the laserjet and inkjet notes are tested, a distinct set of ion markers can be seen and their fingerprint is quite different from the real money.

'The work convincingly demonstrates a relevant application of these techniques in combating currency forgery,' comments Niamh Nic Daeid, a forensic chemist at the University of Strathclyde in the UK. 'The next challenge will be to make this technology widely available to the forensic community as a robust and affordable technique.'

As well as discovering fake money, Eberlin can see this method being used in a preventative way. 'We are already working together with the Brazilian Federal Police and the manufactures in Brazil to find the most effective way to add these chemical signatures, either in ink formulations or as invisible stamps or bar codes, as a new and hard to imitate security measure for Brazilian banknotes,' he says.

Rebecca Brodie
 

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Highlights in Chemical Technology, Volume 2010, 12

http://rsc.org/Publishing/ChemTech/Volume/2010/12/detecting_explosives.asp

Detecting explosives hidden within clothing

12 November 2010

Near infrared (NIR) spectroscopy could be used to detect hazardous chemicals hidden behind clothing, and could improve security screening technology in places such as airports, say UK scientists.

Celine Canal, David Hutchins and colleagues from the University of Warwick detected the explosive ammonium nitrate hidden behind a layer of various clothing materials, from light acrylic to thick denim. 'Light in the NIR wavelength range is invisible to the naked eye, allowing unnoticeable remote detection,' explains Hutchins. The optical components of a spectrometer in the NIR wavelength range are less expensive than for alternative remote detection systems, which use X-rays or terahertz signals, he adds. Unlike X-rays, NIR radiation is not ionising so it is also a safer option for human screening.

The group showed how a person could be screened for hidden chemicals from a remote distance. They set up a light source to illuminate a sample, which consisted of the chemical in a glass container hidden behind a layer of clothing material. The light was transmitted through the clothing and signals were reflected by the chemical and back through the clothing to the detector. The signal was then passed into a spectrometer, which analysed the intensity of the light at each wavelength. By comparing the intensities of light diffused by the clothing material and the hidden chemicals, the group were able to work out a 'fingerprint' for the chemical. They hope that by using statistical methods, this fingerprint can then be recognised automatically in screening applications.

'Identifying materials hidden under clothing is an unsolved challenge for existing security technologies. NIR spectroscopy combined with powerful analysis tools might be a promising answer,' says Jürgen Popp who develops innovative spectroscopic techniques at Friedrich Schiller University in Jena, Germany. However, he points out that that dealing with influences such as perspiration, scent and pollution will be a challenge.

Hutchins' group are working on how to process the data to remove influences from the environment, the packaging around the chemical and multiple clothing layers. They hope that in the future, the system could be added to CCTV cameras, providing a warning from the spectroscopic analysis of a hidden suspicious chemical and an image of the suspect.

Fay Nolan-Neylan
 
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