Water solid phase preparation

Diethylene glycol method. Place 0-5 g. of potassium hydroxide pellets, 3 ml. of diethylene glycol and 0 5 ml. of water in a 10 or 25 ml. distilling flask heat the mixture gently until the alkali has dissolved and cool. Add 1-2 g. of the ester and mix well. Fit the flask with a thermometer and a small water-cooled condenser in the usual way. Heat the flask over a small flame whilst shaking gently to mix the contents. When only one liquid phase, or one hquid phase and one solid phase, remains in the flask, heat the mixture more strongly so that the alcohol distils. Identify the alcohol in the distillate by the preparation of the 3 5 dinitrobenzoate (Section 111,27,2). 

Agulyansky et al. [492, 493] investigated the complex structure and composition of solid phases precipitated by ammonia solution from experimental and industrial niobium and tantalum strip solutions. Fig. 136 shows isotherms (20°C) of Nb205 content versus pH for solutions prepared by the dissolution of (NH4)3NbOF6 and (NH4)2NbOF5 in water and of Nb metal in... 

Prepare the solid-phase extraction (SPE) tube (1 ml LC-18 SPE tube) by conditioning with 1 ml of methanol followed by 1 ml of water. 

It is also possible to perform preparative TLC, developing the sample with AMD technique [36a]. After a solid-phase extraction of the waste water with C18-Empore discs, alkanesulfonate is isolated by using a specially dimensioned TLC plate and by scraping out the surfactant-containing zone. 

PEG polymers are widely used as water soluble supports [99]. Although these polymers suffer from easy loss of PEG oligomers, they are frequently used for the preparation of small organic molecules [100-105] and biopolymers [106,107]. The main benefit of PEG supports is their solubility in water as well as most organic solvents. Also, as opposed to most solid-phase techniques, PEG polymers allow for easy on-bead NMR monitoring. Soluble PEG supports have been used frequently in synthetic microwave chemistry protocols [108-122]. 

In these systems, solid enzyme preparations (e.g. lyophilized or immobilized on a support) are suspended in an organic solvent in the presence of enough aqueous buffers to ensure catalytic activity. Although the amount of water added to the solvent (as a rule of thumb <5% v/v) may exceed its solubility in that solvent, a visible discrete aqueous phase is not apparent because part of it is adsorbed by the enzyme. Therefore, the two phases involved in an organic solvent system are a liquid (bulk organic solvent and reagents dissolved in it) and a solid (hydrated enzyme particles). 

Table 3 Summary of solid-phase extraction techniques applied to the preparation of water samples for the determination of triazine pesticides...

Beef kidney samples were analyzed for atrazine by dispersing 0.5-g portions of kidney with 2-g portions of XAD-7 HP resin for matrix solid-phase dispersion. " By using a mortar and pestle, a powder-like mixture was prepared that was subjected to subcritical extraction using ethanol-modified water at 100 °C and 50 atm. The ethanol-water extract was sampled using a CW-DVB SPME fiber for direct analysis using ion-trap GC/MS, and the recoveries were quantitative for atrazine at the 0.2 mg kg fortification level. 

P.D. McDonald and E.S.P. Bouvier, Solid Phase Extraction Applications Guide and Bibliography, A Resource for Sample Preparation Methods Development, Waters, Milford, MA... 

Many of the analytes of interest for solid phase chemical reference materials are the same as those in seawater, but the need for and the preparation of reference materials for suspended particulate matter and sediments is quite different. The low concentrations of many seawater species and the presence of the salt matrix create particular difficulties for seawater analyses. However while sediments frequently have higher component concentrations than seawater, they also have more complicated matrices that may require unique analytical methods. A number of particulate inorganic and organic materials are employed as paleoceano-graphic proxies, tracers of terrestrial and marine input to the sea, measures of carbon export from the surface waters to the deep sea, and tracers of food-web processes. Some of the most important analytes are discussed below as they relate to important oceanographic research questions. 

A sorption isotherm is completed for each solid particle type and SWMs/ COMs. A range of solid to solution concentrations (i.e., solid solution) was chosen for each solid phase and waste material leachate (e.g., 50-250 mg/l),with about five data points per range. All control and test samples were performed in duplicate. The solution used in the isotherms was prepared by a 24-h batch leaching experiment with the solid test material and distilled water. The material controls consisted of the test material leachate without the solid phase particles. Chemical analyses, expressed either as TOC or as individual organic compound (e.g., aliphatic and aromatic compounds) concentrations relative to the organic carbon content of the SWM/COM, revealed the actual concentrations of various organic constituents in the leachates. Solid phase controls were also prepared for each of the test soils/sediments in order to determine the concentrations of the constituents leached from the solid phase alone. 

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