. First, some applications require not a single analysis but continuous monitoring of the sample itself or some consecutive factors like in technological processes or disperse systems [1] or for in vivo analyses [2]. Another challenge is the determination of low amounts against a highly concentrated matrix (e.g. high purity reagents [3] and [4] or trace components in biological samples against a highly absorbing matrix like hemoglobin or albumin [5] and [6]), which should also be characterized in detail, and with minimum pretreatment. As the signal of the main component overwhelms the other, the applicability of electroanalysis or chromatography is sometimes hindered [7] and [8], and thus require sophisticated separation/isolation techniques