Analytical Instrument Documents

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Documentation in support of your JEOL product.

Instantaneous Detection of Opiates in Single Poppy Seeds

Poppy seed is a common flavoring ingredient that is known to contain small amounts of opiates. Maximum morphine and codeine concentrations are estimated to be about 33 and 14 micrograms respectively per gram of seed. Consumption of typical amounts of baked goods containing poppy seeds has not been shown to cause any ill effects. However, ingestion of poppy seeds may result in false positives from drug tests. Single poppy seeds from different sources were analyzed independently in two different laboratories by using the DART™/AccuTOF™ combination. The resulting mass spectra were nearly identical.

Instantaneous Detection of Illicit Drugs on Currency

The widespread presence of illicit drugs on currency is an indication of the extent of the worldwide substance abuse problem. Remarkably, cocaine can be found on virtually all one-dollar bills in the United States — the upper limit for the general background level of cocaine is estimated to be 13 ng per bill. The Direct Analysis in Real Time (DART™) ion source, combined with the AccuTOF™ mass spectrometer can be used to sample drugs on currency within seconds. No sample preparation (extraction, wipes, etc.) or chromatography is required. The bill is placed in front of the DART and the presence of drugs can be detected immediately. Only a small portion of the bill is sampled at any given time. This allows the analyst to view the distribution of drugs on the surface of a bill, and allows the bill to be retained for reexamination at a later time.

Instantaneous Detection of Explosives on Clothing

The detection of explosives is of vital importance in forensic applications and in preventing criminal or terrorist activity. The analytical detection of explosives on surfaces is normally done by using solvent extractions or wipes and chromatography or chromatography combined with mass spectrometry. This is inefficient because solvent extractions and wipes only result in a partial transfer of material from the surface into the sampling material. Furthermore, the chromatographic analysis can be time-consuming and requires the use of disposable solvents (an environmental concern). The JEOL AccuTOF™ with Direct Analysis in Real Time (DART™) has demonstrated the capability to detect both volatile and involatile explosives on surfaces such as plastic, cloth, concrete, glass, cardboard, metal, and more. No wipes or solvent extractions are required. The method is instantaneous, environmentally friendly, and does not require solvents. An example is shown in this application note.

Identifying “Buried” Information in LC/MS Data

It is not always easy to identify minor unknown components in complex LC/MS datasets. The new DART™ ion source screened for components that were not immediately recognized in LC/MS analysis of tea samples. LC/TOFMS datasets can contain high-resolution, exact-mass data for all ionized components of a complex mixture. Even with concurrent UV detection and chromatographic enhancement software, it is not always easy to identify all of the components that are present in the dataset. Furthermore, suppression effects may mask important information. Here, a new technique known as Direct Analysis in Real Time (DART™) was used to screen tea samples and provide elemental compositions for minor components that were “buried” in LC/MS data collected for tea analysis. DART is a powerful new ionization method that permits direct analysis of solid, liquid, or gas samples at atmospheric pressure and ground potential. DART has been applied to rapid in-situ analysis of a very wide range of materials ranging from drugs to explosives, foods, and beverages.

Identification of Polymers

DART can be used to analyze polymers, cements, resins, and glues by increasing the gas temperature to 450-550° C to induce pyrolysis. This has been applied to a variety of polymers including Nylons, polypropylene and polyethylene, polyethylene terephthalate (PET), polyesters, poly(methyl methacrylate) (PMMA), polycarbonate, phenoxy resin, polystyrene, and cellulose. Examples are shown here for standard samples of Nylon, polystyrene, and cellulose.

Identification of Contamination on Welding Wires Using Cross-Platform Techniques in SEM and Mass Spec

A batch of contaminated welding wire received from a vendor by a customer was causing problems in a manufacturing process. Visual comparison of the clean and contaminated wire did not show any obvious differences, but the contamination was readily observed on backscatter electron images obtained with the JEOL IT300 scanning electron microscope.

GC–TOF-MS and DART–TOF-MS: Challenges in the Analysis of Soft Drinks

The potential of the time-of-flight mass spectrometry (TOF-MS) to innovate the analysis of soft drinks is described using gas chromatography (GC) hyphenated to TOF-MS and a new type of ion source, direct analysis in real time (DART), coupled to high-resolution TOF-MS. Head-space solid-phase microextraction (SPME) was used to isolate/extract volatile compounds followed by GC–TOF-MS to identify tainted compound in contaminated soft drinks. Direct analysis in real time–time-of-flight mass spectrometry (DART–TOF-MS) was also used to obtain negative and positive ion profiles of different soft drinks to determine the presence of various compounds, including antimicrobial preservatives, artificial sweeteners, acidulants and saccharides, without any sample preparation and chromatographic separation.

GC/MS with a DART® Ion Source

GC/MS analysis can be carried out by connecting the GC output to the DART® ion source with a simple interface. Because the GC column is not introduced into vacuum, there are no restrictions on gas flow rates. No fragile electron filament is used. Conditions can be adjusted to produce chemical ionization (CI) mass spectra or mass spectra resembling electron ionization (EI) mass spectra.

Fiber analysis by thermal desorption/pyrolysis DART®

Analyzing fiber samples has always been difficult by DART®. The problem has been that there is no easy way to hold the fiber in the gas stream without losing it into the vacuum system. A fiber can be secured in the DART gas stream with forceps or other means, but if the DART gas is too hot, the fiber can break off and be lost into the mass spectrometer vacuum system through the atmospheric pressure interface. A thermal desorption/pyrolysis stage (The Biochromato, Inc. “ionRocket™”) designed for use with DART produces highly reproducible thermal desorption profiles that show outgassing, additives, and high-quality pyrolysis DART mass spectra for materials. Because fiber samples placed in the disposable copper sample “pots” are not positioned directly in the DART gas stream, a single fiber can be analyzed without risk of loss into the vacuum system.

Elemental Compositions from Exact Mass Measurements and Accurate Isotopic Abundances

Exact masses have been used for decades to calculate elemental compositions for known and unknown molecules. The traditional approach calculates all possible combinations of user-specified atoms that fall within a given error tolerance of a measured mass. The number of possible combinations increases dramatically with increasing mass and as more atoms are included in the search set. In many cases, it is not possible to determine a unique composition based on mass alone. A common source of error in measuring isotopic abundances with scanning mass spectrometers is related to fluctuations in ion current during measurement. The AccuTOF family of mass spectrometers overcomes this problem by analyzing all of the isotopes formed at the same instant. Combined with a high-dynamic-range detector, this provides highly accurate isotopic abundances. It has been shown that accurately measured isotopic abundances can be combined with measured exact masses to dramatically reduce the number of possible elemental compositions for an unknown. It is often possible to deduce a unique elemental composition, facilitating the identification of unknown substances.

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Corona - Glow Discharge (DART Ion Source)

January 28, 2022
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