Methanol-waste solution

Example of a protected amine. The protected amino acid V -ferf-butoxy carbonyl (Boc)-l-lysine, when used as the amine to synthesize the triazine-based ligands, is deprotected prior to screening with protein. Protected immobilized ligands, after washing with the appropriate solvent in a sintered funnel, are immersed in 99% v/v trifluoroacetic acid (TFA) and stirred for 1 h in the fume hood. Methanol is added to dilute the TFA, and the waste solution is carefully disposed of. The matrixes are washed sequentially with methanol and distilled water (3 10 gel... 

Laboratory wastes Add ascorbic acid to waste solution adjust pH to 8 with NaOH centrifuge add methanol to supernatant and centrifuge elute from HPLC column with ammonium acetate/methanol HPLC/UV/ED 5 ng (UV) 4.6 ng (ED) NR Barek et al. 1985... 

Formaldehyde—Alcohol Solutions. These solutions are blends of concentrated aqueous formaldehyde, the alcohol, and the hemiacetal. Methanol decreases the average molecular weight of formaldehyde oligomers by formation of lower molecular weight hemiacetals. These solutions are used to produce urea and melamine resins the alcohol can act as the resin solvent and as a reactant. The low water content can improve reactivity and reduce waste disposal and losses. Typical specifications for commercially available products are shown in Table 7 (117). 

The mobile phase is interesting in that the water is buffered appropriately to complement the dissociation constants of the solutes. A mixture of methanol and acetonitrile is employed, the acetonitrile being used to increase the dispersive interactions in the mobile phase. The reason for the particular solvent mixture is not clear and it would appear that the separation might be achieved equally well by using a stronger solution of methanol alone or a more dilute solution acetonitrile alone. There is no particular advantage to one solvent mixture over another except for the fact that waste acetonitrile produces greater solvent disposal problems than methanol. 

Pankey et al.21 described a rapid, reliable, and specific enzyme multiplied immunoassay technique (EMIT ) for amitriptyline, nortriptyline, imipramine, and desipramine in sera. To overcome crossreactivity, solid phase extraction was included in sample pretreatment. Disposable 1 mL columns packed with covalently labeled silica gel were conditioned with HPLC-grade methanol (1 mL) and then with de-ionized or distilled water (1 mL). Serum (calibrator, control, or patient sample, 500 L) was applied onto the column, eluted to waste, washed with 900 /uL of wash solution containing acetonitrile (236.1 g/L) and ion-pairing reagent in acetate buffer, pH 4.2, washed with 500 fiL of mobile phase solution containing acetonitrile (393.5 g/L) in methanolic phosphate buffer, pH 7.0,... 

The supernatant organic solution might contain active borane. The solution that was removed was treated with methanol to destroy any active borane. The waste containing dimethyl sulfide must be treated appropriately before being discarded. 

HPLC methods can be ntilized for the pre-concentration of aromatic amines from polluted waters on silica gel or octadecyl silica (ODS) colnmns [55], The determination is then performed by RP HPLC using ODS packings as the stationary phases and a mixture of methanol, isopropanol, and water as the mobile phase [55], RP HPLC with diode array detector (DAD) methods coupled on-line with a continnons seqnential anaerobic/aerobic reactor system have been employed in wastewaters treatments [56], A continnons monitoring of the possible presence of aromatic amines in azo dyes wastes is based on indncing in the waste, the reaction of a reduction of the dye, followed by HPLC/ UV or HPLC/MS analysis [57-59], The redncing agent solutions are sodium dithionite or tin(II) chloride in an aqneons acidic medinm at 70°C, followed by SPE [58,59], LLE [60,61], or SEE [60-62],... 

A two- or three-dimensional graph drawn with axes at right angles implies that each factor can take completely independent values and that a response exists for every point on the graph. This may be the case for many factors. If the effects of initial pH and time of an experiment are being studied, for example, it is probably acceptable to set the pH of the solution then allow the experiment to go for as long as required. However, if a simple water/ methanol mobile phase for liquid chromatography is used, it would be a waste of an axis to try to optimize both water and methanol concentration, because what is not water is methanol and vice versa. This is only a one-factor problem—the fraction of water (or methanol). 

Aqueous cyanide effluent containing a little methanol in a 2 m3 open tank was being treated to destroy cyanide by oxidation to cyanate with hydrogen peroxide in the presence of copper sulfate as catalyst. The tank was located in a booth with doors. Addition of copper sulfate (1 g/1) was followed by the peroxide solution (27 1 of 35 wt%), and after the addition was complete an explosion blew off the doors of the booth. This was attributed to formation of a methanol vapour—oxygen mixture above the liquid surface, followed by spontaneous ignition. It seems remotely possible that unstable methyl hydroperoxide may have been involved in the ignition process. See Waste treatment, below. 

Soils, solid wastes, or sludges mixed with water or methanol the aqueous extract or a solution of methanol extract spiked into water, subjected to purge and trap concentration and analyzed as above. 

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