Cocaine, is it really there? Differing sensitivities of immunoassay drug screen and mass spectrometry

2020 ◽  
pp. 493-496
Author(s):  
Hana Vakili ◽  
Khushbu Patel ◽  
Patricia M Jones
Keyword(s):  
Mass Spectrometry ◽  
Drug Screen

Are point-of-care urine drug testing devices suitable for antenatal drug screening? A study verifying the Alere® Drug Screen Test Cup for the detection of six classes of drug in a pregnant population

2021 ◽  
pp. 000456322199069
Author(s):  
Rachel C Dale ◽  
Loretta T Ford ◽  
Catherine Street
Keyword(s):  
Mass Spectrometry ◽  
Drug Use ◽  
Drug Testing ◽  
Urine Analysis ◽  
Point Of Care ◽  
Screen Test ◽  
Drug Screen ◽  
Point Of Care Testing ◽  
National Guidelines ◽  
In Pregnancy

Background Currently, there are no national guidelines for antenatal drug testing. At Colchester Hospital, we use a strategy of screen-only using point-of-care testing to detect illicit drug use in pregnancy. To determine the suitability of this approach, we have compared the results of urine analysis by point-of-care testing with another NHS specialist clinical toxicology service that uses confirmation mass spectrometry. Methods A total of 482 anonymized random urine specimens from antenatal clinics were tested for six drug classes: amphetamine, benzodiazepines, buprenorphine, cocaine, methadone and opiates using the Alere™ Drug Screen Urine Test Cup. The manufacturer’s claims for positive cut-off and result stability were verified using spiked blank urine. Confirmatory testing was performed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) for detection of 26 individual drugs. Results Of 473 urine samples with adequate volume for point-of-care screening, 4.4% tested positive: 19 opiate and 2 cocaine. Concordance between point-of-care screening and UPLC-MS/MS confirmation was 97.9% for all drugs and 78.9% for opiates. Using spiked urine, only positive results for opiates were stable when read up to the manufacturer’s recommended time of 60 min. Conclusions The key advantages of using point-of-care devices to detect drug use in pregnancy are that is convenient and cheap. However, the clinical utility of point-of-care testing is limited by its poor sensitivity. Best practice is to confirm results using a more specific and sensitive method. As a result of this study, we are now reviewing our own procedures to consider introducing routine confirmation by mass spectrometry.

How SIMS microscopy can be used in medicine

1992 ◽  
Vol 50 (2) ◽  
pp. 1602-1603
Author(s):  
Philippe Fragu
Keyword(s):  
Mass Spectrometry ◽  
Biomedical Applications ◽  
Secondary Ion Mass Spectrometry ◽  
Chemical Elements ◽  
Biological Applications ◽  
The Past ◽  
Potential Source ◽  
Secondary Ion ◽  
Chemical Integrity ◽  
Scientific Endeavour

The identification, localization and quantification of intracellular chemical elements is an area of scientific endeavour which has not ceased to develop over the past 30 years. Secondary Ion Mass Spectrometry (SIMS) microscopy is widely used for elemental localization problems in geochemistry, metallurgy and electronics. Although the first commercial instruments were available in 1968, biological applications have been gradual as investigators have systematically examined the potential source of artefacts inherent in the method and sought to develop strategies for the analysis of soft biological material with a lateral resolution equivalent to that of the light microscope. In 1992, the prospects offered by this technique are even more encouraging as prototypes of new ion probes appear capable of achieving the ultimate goal, namely the quantitative analysis of micron and submicron regions. The purpose of this review is to underline the requirements for biomedical applications of SIMS microscopy.Sample preparation methodology should preserve both the structural and the chemical integrity of the tissue.

Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe

1990 ◽  
Vol 48 (2) ◽  
pp. 314-315
Author(s):  
K.K. Soni ◽  
D.B. Williams ◽  
J.M. Chabala ◽  
R. Levi-Setti ◽  
D.E. Newbury
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Equilibrium Phase ◽  
Icosahedral Symmetry ◽  
Ion Microprobe ◽  
X Ray ◽  
Cu Alloys ◽  
Two Phases ◽  
The University ◽  
Secondary Ion

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.

Applications of Time-OF-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

1990 ◽  
Vol 48 (2) ◽  
pp. 308-309
Author(s):  
Bruno Schueler ◽  
Robert W. Odom
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Structural Information ◽  
Time Of Flight ◽  
Biological Tissues ◽  
Polymer Surfaces ◽  
Tof Sims ◽  
Secondary Ions ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) provides unique capabilities for elemental and molecular compositional analysis of a wide variety of surfaces. This relatively new technique is finding increasing applications in analyses concerned with determining the chemical composition of various polymer surfaces, identifying the composition of organic and inorganic residues on surfaces and the localization of molecular or structurally significant secondary ions signals from biological tissues. TOF-SIMS analyses are typically performed under low primary ion dose (static SIMS) conditions and hence the secondary ions formed often contain significant structural information.This paper will present an overview of current TOF-SIMS instrumentation with particular emphasis on the stigmatic imaging ion microscope developed in the authors’ laboratory. This discussion will be followed by a presentation of several useful applications of the technique for the characterization of polymer surfaces and biological tissues specimens. Particular attention in these applications will focus on how the analytical problem impacts the performance requirements of the mass spectrometer and vice-versa.

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