Some Rare Earth Elements Analysis by Microwave Plasma Torch Coupled with the Linear Ion Trap Mass Spectrometry

Abstract

A sensitive mass spectrometric analysis method based on the microwave plasma technique is developed for the fast detection of trace rare earth elements (REEs) in aqueous solution. The plasma was produced from a microwave plasma torch (MPT) under atmospheric pressure and was used as ambient ion source of a linear ion trap mass spectrometer (LTQ). Water samples were directly pneumatically nebulized to flow into the plasma through the central tube of MPT. For some REEs, the generated composite ions were detected in both positive and negative ion modes and further characterized in tandem mass spectrometry. Under the optimized conditions, the limit of detection (LOD) was at the level 0.1 ng/mL using MS2 procedure in negative mode. A single REE analysis can be completed within 2~3 minutes with the relative standard deviation ranging between 2.4% and 21.2% (six repeated measurements) for the 5 experimental runs. Moreover, the recovery rates of these REEs are between the range of 97.6%–122.1%. Two real samples have also been analyzed, including well and orange juice. These experimental data demonstrated that this method is a useful tool for the field analysis of REEs in water and can be used as an alternative supplement of ICP-MS.

Spray-inlet microwave plasma torch ionization tandem mass spectrometry for the direct detection of drug samples in liquid solutions

“…As a novel high‐frequency plasma generator at atmosphere pressure, the MPT ionization source was developed in 1985 at Jilin University of China, and substantial improvements were subsequently made at Indiana University . The traditional applications of the MPT were mainly focused on optical spectroscopy in the excitation source to analyze metallic and nonmetallic elements . Recently, the MPT has begun to be used as an ion source for ambient mass spectrometry.…”

“…Duan and coworkers systematically characterized microwave‐induced plasma desorption/ionization (MIPDI) mass spectrometry and suggested that MIPDI is a "hard‐soft" ion source . Zhu and coworkers used MPT‐MS for direct analysis of various metallic elements with a limit of detection (LOD) as low as 10 −8 g/L . Although ambient ionization methods have been developed for dozens of years, only several studies have been involved in drug abuse detection.…”

Direct Mass Spectrometric Analysis of Zinc and Cadmium in Water by Microwave Plasma Torch Coupled with a Linear Ion Trap Mass Spectrometer

“…is electrophilic while metal ions are general electron donor. Usually, the nitrate radical comes from the air surroundings, but not the sample solutions [25,31].…”

“…More early, MPT had been used as a powerful light source and applied widely in spectrometric instruments [23,24]. Our previous studies [25] have showed that the MPT ion source coupled with a mass spectrometer can is a promising analytical tool in various fields. Adopting the desolvation unit, and injecting aqueous samples through the central-tube of MPT, the MPT mass spectrometry can be used to detect directly sensitively many kinds of metal elements in water, without tedious sample pretreatment.…”

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

“…These make MPT a suitable ionization source for desorption ionization of solid samples. Recently, protonated analytes in liquid samples were also produced by MPT [ 25 ]. Theoretically, the high temperature of MPT allows the observation of ambient thermal dissociation of the analyte ions produced by MPT sources.…”