POSSIBILITIES FOR INTERFERENCE REDUCTION IN ICP-MS/MS SYSTEM USING HE COLLISION CELL

Nowadays one of the most powerful multi-element analysis techniques is an inductively coupled plasma mass spectrometry (ICP-MS) method, but it suffers from some very well-documented spectral interferences which can be very problematic when some samples of different complex matrices and origins are analysed.
Polyatomic (or molecular) ions at the same m/z ratio as the analyte of interest are the reason for different interferences to a wide range of elements to be determined.
At this moment ICP-MS is a standard analytical technique for the measurement of many elements in different kinds of environmental samples (water, soil, plants, etc.) as well as pharmaceuticals and other materials and it is not imaginable without collision/reaction cell but some spectral interferences still
create problems for the determination of several elements. Use of some other isotope with lower natural occurrence or dilution can decrease these interferences, but some industries like semiconductor production or pharmacology require low detection limits and complex chemicals with high purity. Some devices like Agilent 8900 ICP-TripleQuad features a tandem MS/MS configuration, which consists of two scanning quadrupole mass analysers on either side of a collision/reaction cell. This configuration enables to use of ICP-MS in MS/MS mode in which it is possible to resolve difficult spectral interferences in a wide range of sample types using reactive cell gases like O2, H2, NH3, etc. MS/MS mode also can be used for the more difficult elements and problematic interferences that can be encountered in routine analysis, for example, food, sludge, soil, wastewater, and pharmaceuticals. This study aimed to evaluate the possibilities to decrease the impact from polyatomic interferences when using ICP-MS/MS system equipped with a He collision cell.
In this study, several SRM’s were analyzed (Lichen (IAEA 336), Algae (IAEA 392), Algae (IAEA 413), White Cabbage (BCR 679), Sewage sludge (LGC 6181), and Air filters (LGC A2-1365). Measurements were done with Agilent 8900 ICP-MS QQQ) equipped with a micro-mist nebulizer and He collision cell (He gas flow 5.0 mL min-1). Measurements were done in both using single MS and tandem MS/MS.
Results of this study showed that it is possible to significantly decrease quantification limits for 28Si measurements using ICP-MS/MS together with He collision cell while it is impossible to measure using a single MS system due to high interference from atmospheric nitrogen (N2, m/z = 28). Better results are
also obtained for measurements for 39K, where some imprecision of measurements can be due to 38Ar1H (m/z = 39). Better results are also obtained when measuring Na, W, Mo, Cl, and S. Acknowledgement. Research is supported by the Project “Strengthening the doctoral capacity of the University of Latvia within the framework of the new doctoral model” with project dentification No.8.2.2.0 / 20 / I / 006, LU registration No. ESS2021 / 434,
co-financed by the European Social Fund.