The 1994 QUASIMEME Laboratory Performance Study: Nutrients in seawater and standard solutions

The 1994 QUASIMEME (nutrients) Laboratory-Performance Study (LPS) is presented. The yearʹs programme consisted of two periods, December-May and June-November. (These are referred to as Round 2 and Round 3, respectively, the previous 1993 LPS being Round 1.) In each period, participating laboratories were sent two types of sample material, that is seawater samples and a standard solution containing a mixture of nutrient salts. The standard solution required dilution (by participants) and multiple analyses over several weeks in order to assess long-term repeatability. In Round 2, a few laboratories, identified as poor performers in Round 1 (1993), undertook a ‘learning programme’ in which they received, unknowingly, samples identical to those analysed in Round 1. The other laboratories received samples different from those used in Round 1. In Round 3, all laboratories received the same package of samples, different from those used in Round 1 and Round 2. The results clearly indicate that general all-round improvements in data quality have been achieved.