Precision clinical analysis

The accuracy and precision decrease for ill-shaped waves. If, moreover, the composition of the sample with respect to electro-inactive materials that affect the shape of polarographic curves varies from sample to sample (e.g., in samples of biological materials), the error may increase to 5% or even to 20%. However, even this level is often sufficient for clinical analysis, studies of natural products, or other biochemical applications. 

In clinical analysis, precision, accuracy, speed, and low cost are important considerations. These goals have sometimes been achieved by unusual devices, e.g., disposable potentiometric cells made by planar multilayer film technology, similar to photographic films. Reduction of sensor costs has been attempted by mass production of sensors using technologies of the semiconductor industry (ISFETs). There still appears to be some instability problems with ISFET devices and they do not appear to be in routine use in the clinical field. 

C102+), and Zn ( °Ge+, 0 +, Ar N 0+, Ar N N+ 02+ Fe 0+). Although they cannot be fidly eliminated by matrix separation, their effects on analytical accuracy and precision can be reduced in this way. Although chelation/ extraction techniques have been explored for clinical samples [184, 186], ion-exchange chromatography is now considered preferable for high-precision isotopic analysis [187, 188]. 

This protocol is the most rapid and yields information on the ion activity, which is relevant to ecotoxicology and reactivity. Excellent precision is achieved by one point calibration after each measurement point and by careful temperature control, and is routinely used in cmitroUed environments such as clinical analysis. 

Ion-selective electrodes are available for the electro analysis of most small anions, eg, haUdes, sulfide, carbonate, nitrate, etc, and cations, eg, lithium, sodium, potassium, hydrogen, magnesium, calcium, etc, but having varying degrees of selectivity. The most successful uses of these electrodes involve process monitoring, eg, for pH, where precision beyond the unstable reference electrode s abiUty to deUver is not generally required, and for clinical apphcations, eg, sodium, potassium, chloride, and carbonate in blood, urine, and semm. 

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