[en] The advances in electronics and instrumentation have made the mass spectrometers extremely user friendly and are being increasingly used for meeting the challenging applications that call for ultra high sensitivity (e.g. femtogram levels) on one hand and analysis of high molecular weight compounds like proteins and peptides on the other hand. The high precision and accuracy of data obtained by mass spectrometry is unsurpassable and the technique, therefore, occupies a unique position in the field of analytical science to provide reference values for developing/improving other methodologies for analytical work. It is an indispensable tool in a variety of areas including nuclear technology. Papers relevant to INIS are indexed separately