Fast Determination of Ingredients in Solid Pharmaceuticals by Microwave-Enhanced In-Source Decay of Microwave Plasma Torch Mass Spectrometry

Abstract

Rapid qualitative and quantitative analysis of solid samples (e.g., pharmaceutical preparations) by using a small and low-resolution mass spectrometer without MS/MS function is still a challenge in ambient pressure ionization mass spectrometric analysis. Herein, a practically efficient method termed microwave-enhanced in-source decay (MEISD) using microwave plasma torch desorption ionization coupled with time-of-flight mass spectrometry (MPTDI-TOF MS) was developed for fast analysis of pharmaceutical tablets using a miniature TOF mass spectrometer without tandem mass function. The intensity of ISD fragmentation was evaluated under different microwave power values. Several factors, including desorption distance and time that might affect the signal intensity and fragmentation, were systematically investigated. It was observed that both the protonated molecular ions and major fragment ions from the active ingredients in tablets could be found in the full-scan mass spectra in positive ion mode, which were comparable to those obtained by a commercial LTQ-XL ion trap mass spectrometer. The structures of the ingredients could be elucidated in detail using the MEISD method, which promotes our understanding of the desorption/ionization processes in microwave plasma torch (MPT). Quantitative analysis of 10 tablets was achieved by full-scan MPTDI-TOF MS with low limit of detection (LOD, 0.763 mg/g), acceptable relative standard deviation (RSD < 7.33%, n =10), and 10 s for each tablet, showing promising applications in high throughput screening of counterfeit drugs. Graphical Abstractᅟ Electronic supplementary materialThe online version of this article (doi:10.1007/s13361-017-1708-x) contains supplementary material, which is available to authorized users.

Comparative study on ambient ionization methods for direct analysis of navel orange tissues by mass spectrometry

“…Advanced instruments increase the cost of ambient mass spectrometry and limit the spread of its application. Recently, full scan mass spectrum of pharmaceutical preparations was recorded under soft ionization conditions while only characteristic fragments were obtained under highly energetic ionization conditions using a simple time‐of‐flight mass spectrometer . Such studies indicated that the requirements of ambient mass spectrometry analysis for advanced instruments could be satisfied at a reasonable degree by tuning the energy deliverable for the ionization purpose.…”

Sensitive online speciation analysis of arsenic in biological samples by ambient mass spectrometry

“…We further studied the molecular and fragmentation information of arsine under the action of the MPT which, as an efficient ambient ionization source, was applied to As analysis for the first time. 32 It can be seen from Fig. 3A that arsine exhibited a characteristic mass spectrum signal at m / z 204 in negative ion mode.…”

“…Therefore, total inorganic As (iAs(III) + iAs(V)) could be determined aer reduction under the same pH conditions as those of As(III) analysis. Consequently, iAs(V) could be calculated by the subtraction of total inorganic As and iAs(III).We further studied the molecular and fragmentation information of arsine under the action of the MPT which, as an efficient ambient ionization source, was applied to As analysis for the rst time 32. It can be seen from Fig.3Athat arsine exhibited a characteristic mass spectrum signal at m/z 204 in negative ion mode.…”

Interpretation of Ionization Mechanism Responsible for Reagent Ion and Analyte Formation in Microwave-Induced Plasma Desorption Ionization Mass Spectrometry

“…Three samples (nicotinic acid, caffeine, acetaminophen) were discussed primarily. Nicotinic acid, caffeine, and acetaminophen have high proton affinity and contains high PA of nitrogen atoms (PA of nicotinic acid and caffeine are 907, 916 kJ/mol, respectively, higher than that of H 2 O, (H 2 O) 2 ; PA of acetaminophen is unknown but mainly formed protonated molecular ions). Proton-transfer reactions would occur between these samples with PWCs ions.…”

“…Before sample testing, it is expected the chemical compounds intrinsically have high ionization efficiency and low fragmentation degree to accurately and intensively represent the signal intensity changes as a function of distance L. Three samples (nicotinic acid, caffeine, acetaminophen) were discussed primarily. Nicotinic acid, caffeine, and acetaminophen have high proton affinity and contains high PA of nitrogen atoms 57 (PA of nicotinic acid and caffeine are 907, 58 916 kJ/mol, 59 respectively, higher than that of H 2 O, (H 2 O) 2 ; PA of acetaminophen is unknown but mainly formed protonated molecular ions 60 ). Proton-transfer reactions would occur between these samples with PWCs ions.…”