Dr Catia Costa
I was awarded my postgradute degree on the "Detection of cocaine and respective metabolites using fingerprints" from the University of Surrey in April 2017. Currently working at the University of Surrey's Ion Beam Centre (http://www.ionbeamcentre.co.uk/) as a Liaison Fellow. Here are the Ion Beam Centre we are world leading in the field of ion beam modification and ion beam analysis.
Areas of specialism
Ion Beam Analysis;
University roles and responsibilities
- Surrey's Ion Beam Centre Liaison Fellow
Affiliations and memberships
Recent publications have explored the
possibility of using fingerprints to confirm drug use, but
none has yet dealt with environmental contamination
from fingertips. Here we explored the possibility of establishing
an environmental cutoff for drug testing from
a single fingerprint.
Fingerprint samples (n=100) were collected
from the hands of 50 nondrug users before and after
handwashing to establish separate environmental cutoff
values and testing protocols for cocaine, benzoylecgonine,
heroin, and 6-monoacetylmorphine. The cutoff was challenged
by testing the fingerprints of drug-free volunteers
after shaking hands with drug users. Fingerprints from patients
who testified to taking cocaine (n = 32) and heroin
(n = 24) were also collected and analyzed.
A different cutoff value needed to be applied,
depending on whether the fingerprints were collected as
presented or after handwashing. Applying these cutoffs gave
a 0%false-positive rate from the drug-free volunteers. After
application of the cutoff, the detection rate (compared to
patient testimony) for washed hands of patients was 87.5%
for cocaine use and 100% for heroin use.
Fingerprints show enhanced levels of cocaine,
heroin, and their respective metabolites in patients
who testified to taking the substances, compared with the
population of na1¨ve drug users surveyed, and a cutoff
(decision level) can be established. The cutoff is robust
enough to account for small increases in analyte observed
after secondary transfer.
BACKGROUND: Paper spray mass spectrometry6 is a technique
that has recently emerged and has shown excellent
analytical sensitivity to a number of drugs in blood. As an
alternative to blood, fingerprints have been shown to
provide a noninvasive and traceable sampling matrix.
Our goal was to validate the use of fingerprint samples to
detect cocaine use.
METHODS: Samples were collected on triangular pieces
(168 mm2) of washed Whatman Grade I chromatography
paper. Following application of internal standard,
spray solvent and a voltage were applied to the paper
before mass spectrometry detection. A fingerprint visualization
step was incorporated into the analysis procedure
by addition of silver nitrate solution and exposing the
sample to ultraviolet light.
RESULTS: Limits of detection for cocaine, benzoylecgonine,
and methylecgonine were 1, 2, and 31 ng/mL respectively,
with relative standard deviations of less than 33%. No
matrix effects were observed. Analysis of 239 fingerprint
samples yielded a 99% true-positive rate and a 2.5%
false-positive rate, based on the detection of cocaine,
benzoylecgonine, or methylecgonine with use of a single
CONCLUSIONS: The method offers a qualitative and noninvasive
screening test for cocaine use. The analysis
method developed is rapid (4 min/sample) and requires
no sample preparation.
in swabbing for explosive material; (b) developed a method for determining a successful extraction of analyte from the substrate to reduce false negative events; and (c) expanded the range of analytes that can be detected using paper spray to include the peroxide explosive HMTD, as well as nitroglycerine (NG), picric acid (PA) and tetryl. We report the development of a 30 s method for the simultaneous
detection of 7 different explosive materials using PSMS with detection limits below 25 pg, as well as detection of HMTD at 2500 pg, showing an improvement on previously published work.
RATIONALE: Paper spray offers a rapid screening test without the need for sample preparation. The incomplete extraction of paper spray allows for further testing using more robust, selective and sensitive techniques such as liquid chromatography mass spectrometry (LC-MS). Here we develop a two-step process of paper spray followed by LC-MS to (1) rapidly screen a large number of samples and (2) confirm any disputed results. This demonstrates the applicability for testing medication adherence from a fingerprint.
METHODS: Following paper spray analysis, drugs of abuse samples were analysed using LC-MS. All analyses were completed using a Q Exactive" Plus Orbitrap" mass spectrometer. This two-step procedure was applied to fingerprints collected from patients on a maintained dose of the antipsychotic drug quetiapine.
RESULTS: The extraction efficiency of paper spray for two drugs of abuse and metabolites was found to be between 15-35% (analyte dependent). For short acquisition times, the extraction efficiency was found to vary between replicates by less than 30%, enabling subsequent analysis by LC-MS. This two-step process was then applied to fingerprints collected from two patients taking the antipsychotic drug quetiapine, which demonstrates how a negative screening result from paper spray can be resolved using LC-MS.
CONCLUSIONS: We have shown for the first time the sequential analysis of the same sample using paper spray and LC-MS, as well as the detection of an antipsychotic drug from a fingerprint. We propose that this workflow may also be applied to any type of sample compatible with paper spray, and will be especially convenient where only one sample is available for analysis.
Fingerprints have been proposed as a promising new matrix for drug testing. In previous work it has been shown that a fingerprint can be used to distinguish between drug users and non-users. Herein, we look at the possibility of using a fingerprint to distinguish between dermal contact and administration of heroin.
Fingerprint samples were collected from (a) 10 patients attending a drug rehabilitation clinic (b) 50 non-drug users (c) participants who touched 2 mg street heroin, before and after various hand cleaning procedures. Oral fluid was also taken from the patients. All samples were analysed using a liquid chromatography ? high resolution mass spectrometry (LC-HRMS) method validated in previous work for heroin and 6-AM. The HRMS data was analysed retrospectively for morphine, codeine, 6-acetylcodeine and noscapine.
Heroin and 6-AM were detected in all fingerprint samples produced from contact with heroin, even after handwashing. In contrast, morphine, acetylcodeine and noscapine were successfully removed after handwashing.
In patient samples, the detection of morphine, noscapine and acetylcodeine (alongside heroin and 6-AM) gave a closer agreement to patient testimony on whether they had recently used heroin use than the detection of heroin and 6-AM alone.
This research highlights the importance of washing hands prior to donating a fingerprint sample to distinguish recent contact with heroin from heroin use.