Ambient Pressure Laser Desorption—Chemical Ionization Mass Spectrometry for Fast and Reliable Detection of Explosives, Drugs, and Their Precursors

Rapid Separation and Detection of Drugs in Complex Biological Matrix Using TD-CDI Mass Spectrometer

The drug detection technology plays a pivotal role in the domains of pharmaceutical regulation and law enforcement. In this study, we introduce a method that combines thermal desorption corona discharge ionization (TD-CDI) with mass spectrometry for efficient drug detection. The TD-CDI module, characterized by its compact and simple design, enables the separation of analytes within seconds and real-time presentation of one or two analyte peaks on the mass spectrum most of the time, which reduces matrix interference and improves detection performance. Through experimental investigation, we studied the characteristics of TD-CDI for analyte separation and detection, even with the same mass number, and optimized the TD-CDI approach. TD-CDI-MS was employed for the rapid detection of drugs in various traditional medicine, food products, and human samples. Additionally, by utilizing TD-CDI for segmented hair direct analysis, it becomes possible to trace the drug usage cycle of individuals. This underscores the feasibility of the proposed analytical method within the realm of drug detection.

Non-Contact, Continuous Sampling of Porous Surfaces for the Detection of Particulate and Adsorbed Organic Contaminations by Low-Temperature Plasma Coupled to Ion Mobility Spectrometer

Chemical analysis of hazardous surface contaminations, such as hazardous substances, explosives or illicit drugs, is an essential task in security, environmental and safety applications. This task is mostly based on the collection of particles with swabs, followed by thermal desorption into a vapor analyzer, usually a detector based on ion mobility spectrometry (IMS). While this methodology is well established for several civil applications, such as border control, it is still not efficient enough for various conditions, as in sampling rough and porous surfaces. Additionally, the process of thermal desorption is energetically inefficient, requires bulky hardware and introduces device contamination memory effects. Low-temperature plasma (LTP) has been demonstrated as an ionization and desorption source for sample preparation-free analysis, mostly at the inlet of a mass spectrometer analyzer, and in rare cases in conjunction with an ion mobility spectrometer. Herein, we demonstrate, for the first time, the operation of a simple, low cost, home-built LTP apparatus for desorbing non-volatile analytes from various porous surfaces into the inlet of a handheld IMS vapor analyzer. We show ion mobility spectra that originate from operating the LTP jet on porous surfaces such as asphalt and shoes, contaminated with model amine-containing organic compounds. The spectra are in good correlation with spectra measured for thermally desorbed species. We verify through LC-MS analysis of the collected vapors that the sampled species are not fragmented, and can thus be identified by commercial IMS detectors.

Integrating the MasSpec Pen with Sub-Atmospheric Pressure Chemical Ionization for Rapid Chemical Analysis and Forensic Applications

Analytical methods that allow rapid, sensitive, and specific chemical measurements are central to forensic analysis and essential to accelerating compound screening and confirmation. We have previously reported the development of the MasSpec Pen technology as an easy-to-use and disposable hand-held device integrated to a mass spectrometer for direct analysis and molecular profiling of biological samples. In this Technical Note, we describe a new apparatus that integrates the MasSpec Pen device with a subatmospheric pressure chemical ionization (sub-APCI) source and an ion trap mass spectrometer for detection and semiquantitative analysis of forensic-related compounds. Coupling the MasSpec Pen device to a sub-APCI source allowed semiquantitative analysis of the drugs cocaine and oxycodone, the agrochemicals atrazine and azoxystrobin, and the explosives trinitrotoluene and dinitroglycerin in under 20 s. Using chemical ionization, improved reproducibility and sensitivity for targeted chemical detection and compound identification was achieved while maintaining the user-friendly features of the hand-held MasSpec Pen device. Limits of detection in the high picogram to low nanogram range were obtained for the compounds analyzed, which are within the range of federal screening cutoffs and those reported for other ambient ionization MS techniques. Altogether, the MasSpec Pen sub-APCI system described enabled rapid and semiquantitative chemical analysis for forensic applications and could be further adapted and applied to other areas of chemical testing.

Trace Detection and Chemical Analysis of Homemade Fuel-Oxidizer Mixture Explosives: Emerging Challenges and Perspectives

The chemical analysis of homemade explosives (HMEs) and improvised explosive devices (IEDs) remains challenging for fieldable analytical instrumentation and sensors. Complex explosive fuel-oxidizer mixtures, black and smokeless powders, flash powders, and pyrotechnics often include an array of potential organic and inorganic components that present unique interference and matrix effect difficulties. The widely varying physicochemical properties of these components as well as external environmental interferents and background challenge many sampling and sensing modalities. This review provides perspective on these emerging challenges, critically discusses developments in sampling, sensors, and instrumentation, and showcases advancements for the trace detection of inorganic-based explosives.

Interpol review of detection and characterization of explosives and explosives residues 2016-2019

This review paper covers the forensic-relevant literature for the analysis and detection of explosives and explosives residues from 2016-2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/Resources/Documents#Publications.

Highly selective and sensitive online measurement of trace exhaled HCN by acetone-assisted negative photoionization time-of-flight mass spectrometry with in-source CID

Exhaled hydrogen cyanide (HCN) has been extensively investigated as a promising biomarker of the presence of Pseudomonas aeruginosa in the airways of patients with cystic fibrosis (CF) disease. Its concentration profile for exhalation can provide useful information for medical disease diagnosis and therapeutic procedures. However, the complexity of breath gas, like high humidity, carbon dioxide (CO₂) and trace organic compounds, usually leads to quantitative error, poor selectivity and sensitivity for HCN with some of existing analytical techniques. In this work, acetone-assisted negative photoionization (AANP) based on a vacuum ultraviolet (VUV) lamp with a time-of- flight mass spectrometer (AANP-TOFMS) was firstly proposed for online measurement of trace HCN in human breath. In-source collision-induced dissociation (CID) was adopted for sensitivity improvement and the signal response of the characteristic ion CN^- (m/z 26) was improved by about 24-fold. For accurate and reliable analysis of the exhaled HCN, matrix influences in the human breath including humidity and CO₂ were investigated, respectively. A Nafion tube was used for online dehumidification of breath samples. Matrix-adapted calibration in the concentration range of 0.5-50 ppbv with satisfactory dynamic linearity and repeatability was obtained. The limit of quantitation (LOQ) for HCN at 0.5 ppbv was achieved in the presence of 100% relative humidity and 4% CO₂. Finally, the method was successfully applied for online determination of human mouth- and nose-exhaled HCN, and the nose-exhaled HCN were proved to be reliable for assessing systemic HCN levels for individuals. The results are encouraging and highlight the potential of AANP-TOFMS with in-source CID as a selective, accurate, sensitive and noninvasive technique for determination of the exhaled HCN for CF clinical diagnosis and HCN poisoning assessment.

Utilizing Surface Acoustic Wave Nebulization (SAWN) for the Rapid and Sensitive Ambient Ionization Mass Spectrometric Analysis of Organic Explosives

When considering incident investigations and security checks focused on energetic materials, there is an ongoing need for rapid, on-scene chemical identification. Currently applied methods are not capable of meeting all requirements, and hence, portable mass spectrometry is an interesting alternative although many instrumental challenges still exist. To be able to analyze explosives with mass spectrometry outside the traditional laboratory, suitable ambient ionization methods need to be developed. Ideally such methods are also easily implemented in the field requiring limited to no power sources, gas supplies, flow controllers, and heating devices. For this reason, the potential of SAWN (surface acoustic wave nebulization) for the ambient ionization and subsequent mass spectrometric (MS) analysis of organic explosives was investigated in this study. Excellent sensitivity was observed for nitrate-based organic explosives when operating the MS in negative mode. No dominant adduct peaks were observed for the peroxides TATP and HMTD with SAWN-MS in positive mode. The MS spectra indicate extensive fragmentation of the peroxide explosives even under the mild ionization conditions provided by SAWN. The potential of SAWN-MS was demonstrated with the correct identification of nitrate-based organic explosives in pre- and post-explosion case samples in only a fraction of the time and effort required for the regular laboratory analysis. Results show that SAWN-MS can convincingly identify intact organic energetic compounds and mixtures but that sensitivity is not always sufficient to detect traces of explosives in post-explosion residues.