Sequential multiple analyser

The sequential multiple analysers (SMAs) were later developments and they were much more complex in design and included a computer. They could analyse each sample for several constituents simultaneously, the number of channels determining this capacity, i.e. 6, 12 or 20. These instruments were developed primarily for hospital clinical chemistry laboratories to allow an overall assessment of the chemical composition of blood samples. They have now been superseded by other types of analysers. 

K. Toda, Y. Hato, K. Mori, S.I. Ohira, T. Namihira, Sequential multiple analyses of atmospheric nitrous acid and nitrogen oxides, Talanta 71 (2007) 1652-1660. 

The second option is typically represented by the Technicon SMAC (Sequential Multiple Analyzer plus Computer) I and II, which are expensive and complex analytical systems capable of determining up to 20 parameters per sample at a rate of 150 samples per hour [27]. These analysers consist of the following components, all of which are governed by a central computer ... 

A group sequential approach was planned to discharge the 1.3 threshold. The significance levels for the multiple analyses were based on the Lan-DeMets spending function with an O Brien-Fleming boundary. The first analysis to discharge it would be conducted at the time when the meta-analysis to discharge the 1.8 threshold was performed. The next planned interim meta-analysis would be conducted when approximately 500 MACE-plus events had accrued, and a final interim analysis was planned to occur after approximately 700 events had accumulated, if the E3... 

By its nature, therefore, the group sequential design involves the possibility of multiple testing. In this example it is possible that five analyses could be conducted on data collected in this clinical trial. As discussed in Section 7.10, there is an inherent problem with multiple testing. As more tests are performed, it becomes increasingly likely that a Type I error will occur, i.e., that a result will erroneously be declared as statistically significant. As also noted at that point, however, the problem can be addressed completely satisfactorily by taking appropriate statistical care. 

Gel electrophoresis is such an important technique for protein and nucleic add analysis, that it was natural to try and develop capillary-based electrophoretic methods. Although this has been achieved in prindple, CGE has not yet supplanted the classical vertical or horizontal electrophoresis techniques. This is probably due to the fact that with classical techniques it is possible to analyse multiple samples simultaneously, and also that the equipment and techniques are relatively simple. In contrast, CE analyses are usually carried out sequentially, the equipment is much more expensive, and the experimental approach more involved. However, CGE has several important advantages, notably high throughput rate, direct quantitation, and ease of automation these advantages are... 

The modern TIMS instrument consists of an ion-source chamber, flight-tube, sector magnet, and ion-collector chamber. Depending upon the manufacturer and age of the instrument as many as 20 samples can be mounted together in the ion-source chamber and analysed sequentially. The ion-collector chamber may include an array of up to 9 multiple Faraday collectors as well as secondary electron amplification devices allowing ion currents from 1 x 10 A to less than 1 X 10 A to be measured. Since these instruments are designed to measure isotope abundance ratios with high accuracy and precision, the mass spectrum is well-resolved and the spectral peaks are broad with flat tops. 

Other important issues are to do with the basic structure of trials. For example, what are the appropriate comparator treatments How many should be studied simultaneously Will the object of the trial be to find differences or to demonstrate equivalence Should a parallel group study or a cross-over trial be used How many centres should be used What should the block size be If a cross-over trial is employed will it be necessary to use incomplete blocks (These are designs in which each patient receives only a subset of the treatments being studied.) How long should the treatments be applied When should values be measured How should they be combined Should the results be analysed sequentially If the trial is to be blinded, how should this be achieved Is stratification desired What factors should be included in the analysis What is the general approach to be adopted What is the strategy for dealing with multiplicity of outcomes ... 

Commercial on-stream XRF analysers for Hquid process streams are produced by a number of manufacturers (see Appendix). These can either be configured for monitoring single or multiple streams. In most cases, the X-ray monitoring head (source and detector) moves sequentially from one flow cell to another for sequential monitoring. Solid reference samples are normally also incorporated in one or more of the positions monitored by the measurement head and used to calibrate and correct for instmmental drift In many instances, however, plumbing multiple... 

---