"One should rather go horne and mesh a net than jump into the pond and dive far fishes" (Chinese proverb) Recognizing the precise analytical question and planning the analysis according- ly is certainly the first prerequisite for successful trace and ultratrace determina- tions. The second prerequisite is to select the method appropriate to the analyti- cal specification. The method itself consists of a set of available tools. The third prerequisite is that analysts and operators know the methods weH enough to enjoy challenging themselves as weH as the methods and are rewarded by the joy of...