“…More recently, analytical techniques such as neutron activation analysis (Shukla et al 1978, Murty et al 1983, infrared absorption spectrometry (Terashima 1979(Terashima , 1988 and automatic elemental analyser (Din and Jones 1978, McGeehan and Naylor 1988, David et al 1989, Artiola 1990, Terashima 1993, Matejovic 1997, Kowalenko 2001) have been used. Coulometric titration (Atkin and Somerfield 1994), flame photometry (Marcó et al 2001), inductively coupled plasma-atomic emission spectrometry (ICP-AES, Okai et al 2001), high-resolution inductively coupled plasma-mass spectrometry (HP-ICP-MS, Makishima and Nakamura 2001), and elemental analyser-continuous flow isotope ratio mass spectrometry (EA-CFIRMS, Studley et al 2002) were reported as methods covering only S determination. Many data on the concentrations of C, H, N and S in geological reference materials have been reported, but not all international geochemical reference materials have certified values for these elements (e.g., , 1992, Govindaraju 1994, Imai et al 1996.…”