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•Urinary anabolic steroids were detected with high sensitivity using LPTD-DBDI-MS.•Anabolic steroids were directly ionized using DBDI without any adduct formation.•Analytical figures ...of merit are demonstrated using suitable internal standards.
Rapid detection of trace level anabolic steroids in urine is highly desirable to monitor the consumption of performance enhancing anabolic steroids by athletes. The present article describes a novel strategy for identifying the trace anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption (LPTD) coupled to dielectric barrier discharge (DBD) ionization mass spectrometry. Using this method the steroid molecules are enriched within a liquid droplet during the thermal desorption process and desorbed all-together at the last moment of droplet evaporation in a short time domain. The desorbed molecules were ionized using a dielectric barrier discharge ion-source in front of the mass spectrometer inlet at open atmosphere. This process facilitates the sensitivity enhancement with several orders of magnitude compared to the thermal desorption at a lower temperature. The limits of detection (LODs) of various steroid molecules were found to be in the range of 0.05–0.1ngmL−1 for standard solutions and around two orders of magnitude higher for synthetic urine samples. The detection limits of urinary anabolic steroids could be lowered by using a simple and rapid dichloromethane extraction technique. The analytical figures of merit of this technique were evaluated at open atmosphere using suitable internal standards. The technique is simple and rapid for high sensitivity and high throughput screening of anabolic steroids in urine.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This work describes the development and application of a new thermal desorption technique that makes use of the Leidenfrost phenomenon in open ion sources at atmospheric pressure for direct mass ...spectrometric detection of ultratrace levels of illicit, therapeutic, and stimulant drugs, toxicants, and peptides (molecular weight above 1 kDa) in their unaltered state from complex real world samples without or with minor sample pretreatment. A low temperature dielectric barrier discharge ion source was used throughout the experiments and the analytical figures of merit of this technique were investigated. Further, this desorption technique coupled with other ionization sources such as electrospray ionization (ESI) and dc corona discharge atmospheric pressure chemical ionization (APCI) in open atmosphere was also investigated. The use of the high-resolution ‘Exactive Orbitrap’ mass spectrometer provided unambiguous identification of trace levels of the targeted compounds from complex mixtures and background noise; the limits of detection for various small organic molecules and peptides treated with this technique were at the level of parts per trillion and 10
–9
M, respectively. The high sensitivity of the present technique is attributed to the spontaneous enrichment of analyte molecules during the slow evaporation of the solvent, as well as to the sequential desorption of molecules from complex mixtures based on their volatilities. This newly developed desorption technique is simple and fast, while molecular ions are observed as the major ions.
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For the real time and direct analysis of chemical constituents from living beings and dry sample, sheath-flow probe electrospray ionization mass spectrometry (SF-PESI-MS) has been newly developed. ...The components from dry or semidry biological tissues can be extracted using the solvent and picked up by the needle for electrospray. This technique was applied to real-time pesticide analysis of living plants. The results have been validated with that of a well-known system, liquid extraction surface analysis mass spectrometry (LESA-MS). It is demonstrated that SF-PESI-MS can produce reasonable ionization efficiency, which is confirmed by LESA-MS.
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We have examined several combinations of solvents and probes with the aim of optimizing the ionization conditions for biomolecules e.g., proteins, peptides and lipids by negative mode probe ...electrospray ionization mass spectrometry (PESI-MS). With the data presented in this study, negative-mode PESI-MS can be considered as a potential tool for biomolecular analysis and cancer diagnostics because of its simplicity in instrumental configuration. A sharper sampling probe was found to be better for obtaining high quality mass spectra because it can generate stable electrospray without the occurrence of gas breakdown. Although the best conditions may depend on each sample, aqueous organic solvent solutions, especially isopropanol-H(2)O (1/1) with a pH of ≥7, are shown to be preferable for negative-mode PESI-MS, which was successfully applied to colon cancer diagnosis.
Aromatic amines are one of the sources of carcinogenicity in cigarette and tobacco smoke. Accurate quantification of these chemicals is needed to assess public health risk. A new validated rapid, ...sensitive and analyte specific liquid chromatography/electrospray ionization tandem mass spectrometric (LC/MS/MS) method has been developed for the simultaneous determination of six aromatic amines in mainstream cigarette smoke using research reference cigarette 2R4F. Three popular Indian brand cigarettes were also analyzed using the same procedure. The limit of detection of this method ranged from 0.04 to 0.59
ng/cig using an injection volume of 7
μl. The identification of each amine was established by chromatographic retention times, analyte specific fragmentation pattern and relative peak area ratios of two product/precursor ion pairs. The method showed excellent reproducibility and was also rapid, selective and robust for aromatic amine determination from cigarette smoke.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The present paper describes the development and validation of a new reversed-phase liquid chromatography–electrospray ionization tandem mass spectrometric method (RP-HPLC–ESI-MS/MS) for simultaneous ...determination of pyridine, 2-picoline, 4-picoline and quinoline from mainstream cigarette smoke. Liquid–liquid extraction followed by solid-phase extraction was applied to extract the target analytes from cigarette smoke. Baseline chromatographic separation was achieved by utilizing a Zorbax SB-Aq (4.6
×
150
mm, 5
μm) column in gradient chromatographic conditions with acetonitrile and ammonium acetate buffer as mobile phases. Popular commercially available Indian brand filtered and non-filtered cigarettes were analyzed using the same method. The identification of each chemical was established by chromatographic retention times, analyte specific fragmentation patterns and relative peak area ratios of two product/precursor ion pairs. The limit of detection of this method ranged from 1.74 to 14.32
ng/cig using an injection volume of 20
μl. The reproducibility of this method is excellent and better standard deviations were obtained compared to literature reported values for these chemicals. RSD value is less than 9% for all analytes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
To perform remote and direct sampling for mass spectrometry, solid probe assisted nanoelectrospray ionization (SPA-nanoESI) has been newly developed. After capturing the sample on the tip of the ...needle by sticking it to the biological tissue, the needle was inserted into the solvent-preloaded nanoESI capillary from the backside. NanoESI gave abundant ion signals for human kidney tissues and the liver of a living mouse. The method is easy to operate and versatile because any biological specimen could be sampled away from the mass spectrometer. Minimal invasiveness is another merit of this method.
Desorption in Mass Spectrometry Usmanov, Dilshadbek Tursunbayevich; Ninomiya, Satoshi; Chen, Lee Chuin ...
Mass Spectrometry,
01/2017, Volume:
6, Issue:
2
Journal Article
Open access
In mass spectrometry, analytes must be released in the gas phase. There are two representative methods for the gasification of the condensed samples, i.e., ablation and desorption. While ablation is ...based on the explosion induced by the energy accumulated in the condensed matrix, desorption is a single molecular process taking place on the surface. In this paper, desorption methods for mass spectrometry developed in our laboratory: flash heating/rapid cooling, Leidenfrost phenomenon-assisted thermal desorption (LPTD), solid/solid friction, liquid/solid friction, electrospray droplet impact (EDI) ionization/desorption, and probe electrospray ionization (PESI), will be described. All the methods are concerned with the surface and interface phenomena. The concept of how to desorb less-volatility compounds from the surface will be discussed.
A sensitive, reliable, and reproducible headspace gas chromatography-flame ionization detection method was developed and validated to detect and quantify low levels of tert-butyl nitrite (TBN). TBN ...is a reagent commonly used by synthetic chemists for nitrogen insertion reactions and is also a potential mutagenic impurity due to a structurally alerting nitrite group. However, there is an inherent analytical challenge in the quantification of TBN due to its chemical instability in solution (e.g., degradation of TBN to tert-butyl alcohol, TBA, in protic solvents). The proposed methodology is based on stabilizing TBN in solution by adding imidazole to a sample diluent before static headspace gas chromatographic analysis. The gas chromatography method utilizes a high-polarity poly(ethylene glycol) stationary phase that provides the resolution of TBN from an interference peak in the sample matrix and facilitates the attainment of the required sensitivity of the TBN peak. The limit of detection (LOD) and limit of quantitation (LOQ) of this method were established as 0.05 μg mL–1 (0.05 ppm) and 0.15 μg mL–1 (0.15 ppm), respectively. Method validation experiments indicated excellent analytical performance of the method with respect to specificity (resolution of ∼2.2 from a matrix interference peak), linearity (range: 16.7–1000% of the working concentration), precision (relative standard deviation, RSD, of 1.0% for n = 6 at LOQ level), and recovery (94% at LOQ level). This is the first report of a practical strategy to stabilize TBN for its trace-level quantification.
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