ABSTRACT
Pencil lead is shown to be an effective matrix and calibrant in matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry. Various groups of analytes, including peptides, polymers and actinide metals, can be readily ionised using MALDI when deposited onto a pencil lead matrix. The matrix is seen to have advantages in sample preparation relating to its hydrophobic properties and almost complete suppression of the matrix during analysis. Using pencil lead as a matrix is a quick and convenient method of qualitative analysis and has been shown to be quantitative for the isotope ratio analysis of actinide metals.
Subject(s)
Actinoid Series Elements/analysis , Actinoid Series Elements/standards , Graphite/analysis , Graphite/standards , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization/standards , Calibration/standards , Reference Standards , Reproducibility of Results , Sensitivity and Specificity , Uranium/analysis , Uranium/standardsABSTRACT
In the frame of the re-certification measurements of the IAEA-375 soil reference material the activity concentration of four actinoids (U, Th, Pu and Am) was determined. The method is based on microwave digestion or aqua regia leaching, separation by extraction chromatography and alpha-particle counting source preparation by co-precipitation or electro-deposition. This article describes some of the problems encountered during the validation of the sample preparation method and their solutions.
