This chapter describes some of the more advanced instrumental methods which may be used for the determination of nutrients, major ions and trace elements, together with the analytical techniques for total, inorganic and organic carbon. Some of these techniques are particularly useful for the detailed analysis of sediments, particularly suspended sediments (see Chapter 13) and for the chemical analysis of biota (see Chapter 11). Although these techniques have been classified here as "dvanced instrumental analysis" some, such as flame photometry, do not require expensive equipment and are often reliable and appropriate methods for water quality monitoring.