Talanta 65 (2005) 1270–1278 Multielemental characterisation of cobalt by glow discharge quadrupole mass spectrometry Shekhar Raparthi a,∗ , J. Arunachalam a , Niranjan Das b , A.M. Srirama Murthy b a National Centre for Compositional Characterisation of Materials, Bhabha Atomic Research Centre, ECIL Post, Hyderabad 500062, India b Defence Metallurgical Research Laboratory, Kanchanbagh Post, Hyderabad 500058, India Received 16 June 2004; received in revised form 25 August 2004; accepted 2 September 2004 Available online 6 October 2004 Abstract Multielemental determination and the assessment of purity of cobalt metal used in the preparation of Ni-based super-alloys have been carried out by glow discharge quadrupole mass spectrometry (GD-QMS). Relative sensitivity factors (RSF) generated from certified iron matrix reference samples (NIST 663 and 664 low alloy steel pin standards) could be used for the determination of different trace element constituents of the sample. Different wet chemical procedures were also carried out for the determination of the trace constituents in the sample. The GD-QMS results are in reasonably good agreement with those obtained from wet chemical procedures, validating the use of the RSF values generated on low alloy steel standards for the computation of trace element concentrations in cobalt metal. A variety of molecular ions formed through the reaction of cobalt (matrix) with the discharge gas (argon) were also detected. © 2004 Elsevier B.V. All rights reserved. Keywords: Glow discharge quadrupole mass spectrometry; Cobalt; Relative sensitivity factors; Multielemental characterisation 1. Introduction Cobalt metal has been used in the production of magnetic alloys, cobalt and nickel based superalloys and sputtering tar- gets in the field of advanced electronic devices such as ULSI [1–3]. It is a second major component in the nickel based superalloys. These superalloys have been used in the manu- facture of various components such as vanes or combustion chambers in gas turbines and aero-engines. These super al- loys are designed almost to their theoretical limits of alloying with a variety of (not less than 10) elements for optimum com- bination of various alloy characteristics. A little addition of any other element from either raw materials or melting cru- cible and other refractory linings can affect the properties and performance of engine parts [4–6]. Therefore, it is essential to develop analytical techniques for the accurate determination of impurity levels at every processing step starting from raw ∗ Corresponding author. Tel.: +91 4027121365; fax: +91 4027125463. E-mail address: shekhar raparthi@rediffmail.com (S. Raparthi). materials. As the cobalt metal is one of the major constituent in the superalloys, many impurities in these alloys can come from the cobalt metal used. Thus it is essential to assess the purity of the cobalt, through the determination of other trace element impurities. Some trace elements, even at levels of 0.5 mg kg -1 , are know to be detrimental to the performance of the superalloy materials [6,7]. Hence the impurity specifications of super- alloy demand an overall multielemental analysis and assess- ment of purity. Several analytical techniques/procedures have been de- veloped for the determination of trace constituents in met- als. The solution-based multielemental techniques, such as inductively coupled plasma optical emission spectrome- try (ICP-OES) and inductively coupled plasma mass spec- trometry (ICP-MS), usually require the separation of ma- trix/constituent elements to minimize interferences and sig- nal suppressions. Chemical separation of the matrix from all other minor or trace constituents is not possible in a sin- gle step. Many separation procedures found in literature are 0039-9140/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.talanta.2004.09.001