Direct water injection cycles

Volatilised tin species were trapped from the same or replicate water samples following rapid injection of aqueous, excess sodium borohydride solution directly into the P/T sparging vessel immediately prior to beginning the P/T cycle. 

An SPE cartridge can be used multiple times, especially after the samples are pretreated with protein precipitation. Bourgogne et al. (2005) quantitated talinolol, a p -adrenoceptor antagonist used to treat arterial hypertension and coronary heart disease, in human plasma. The sample was first precipitated with perchloric acid and the supernatant was injected directly. An Xterra MS analytical column (50 x 4.6 mm, 3.5 [m, Waters) with a C18 recolumn filter (4x2 mm, 3.5 /.mi, Phenomenex) and a C8 EC cartridge were chosen. The cycle time was 4.8 min and linear range was 2.5 to 200 ng/mL. Protein precipitation allowed the SPE cartridge to be used for more than 90 injections. 

As outlined in the previous section, a number of amines are used for conditioning and pH adjustment of cooling waters, which can also contain corrosive ions. Because these amines are added at the mg/L level, their purity also has to be investigated. The technique of Autoneutralization has proved to be suitable for identifying anions thus, the correlative amine is neutralized prior to its analysis. As an example. Fig. 9-66 shows the analysis of anions in 40% monoethanol-amine by direct injection of a lOO-pL sample after two neutralization cycles [114]. An lonPac AS12A anion exchanger was used as a stationary phase and a carbon-ate/bicarbonate mixture as an eluant. If a pre-concentration technique is used instead of direct injection, those anions can also be detected at a sub-pg/L level in such matrix. 

To extend reclaimer washing cycles, steam was injected directly into the shell side of the reclaimer. This diluted the amine and reduced the reclaimer temperature. To maintain the system water balance, only 100% MEA was used as make-up to the lean amine storage tank. When the reclaimer contents had noticeably thickened (usually after two weeks), it was washed out. After three such cycles, the particulate content of the lean amine had been reduced by 80%. 

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