Collective Volumes 1 through 4 and Volume

This index comprises the names of contributors to Volume 55 only For previous volumes see Collective Volumes 1 through 4 and Volume 54... 

Suspend the residue with 0.25 mL of n-hexane-ethyl acetate (9 1, v/v) and apply to the Bond Elut SI (100-mg) cartridge column. Wash the test-tube with 0.25 mL of n-hexane-ethyl acetate (9 1, v/v) and with 0.75 mL of n-hexane-ethyl acetate (4 1, v/v) and apply to the cartridge column. Pass the elution solvent [0.5 mL of n-hexane-ethyl acetate (3 1, v/v) and 0.5 mL of n-hexane-ethyl acetate (2 1, v/v)] through the cartridge and collect into an Eppendorf tube (total volume ca 1 mL). Concentrate the eluate under an N2 gas flow at about 40 °C and dissolve the residue in 1 mL of toluene. 

For milk, transfer the entire sample extract into a separatory funnel (250-mL), add an equivalent volume of dichloromethane plus a half equivalent volume of sodium chloride solution (5%, w/v). Shake the separatory funnel for 2 min and allow the phases to separate. Partially fill a glass filter funnel with anhydrous sodium sulfate (approximately 10 g) and filter the lower dichloromethane layer through the sodium sulfate, collecting the filtrate in a round-bottom flask (250-mL). Wash the sodium sulfate with dichloromethane (5 mL) and collect the washings in the same round-bottom flask. Rotary evaporate the sample to dryness under reduced pressure with a water-bath temperature of 40 °C. Dissolve the residue in 4 mL of ethyl acetate-toluene (3 1, v/v) and transfer the solution to a suitable vial ready for GPC cleanup. 

Methyl l-methyl-4-nitropyrrole-2-carboxylate (4 450 g, 2.44 mol) was dissolved in EtOAc (8L). A slurry of 10% Pd/C (40 g) in EtOAc (800 mL) was then added and the mixture was stirred under a slight positive pressure of H2 (ca. 1.1 atm) for 48 h. Pd/C was removed by filtration through Celite and washed with EtOAc (1 x 50 mL) and the volume of the mixture was reduced to ca. 500 mL cold Et20 (7L) was added and HC1 gas gently bubbled through the mixture. The precipitated amine hydrochloride was then collected by filtration to give a white powder yield 380 g (82%). 

Figure 18.4 The time required for buffer exchanges can be sufficient for evaporation to affect the concentration of ions. Demonstration that the collected Mg2+ concentration can systematically increase with time. Flow-through was collected at 1, 10, and 20 or 30 min (corresponding to 450, 250, and 100 or 20 /iL of solution remaining in the top chamber) during the final round of buffer equilibration. Deviations from the starting buffer concentration (1 mM Mg2+, 20 mM Na+, and 16 mM cacodylate) are plotted for equilibrium conditions that affect total evaporation. Buffer exchanges were carried out at 25 °C and retained volume of 20 jiL (O), 25 °C and retained volume of 100 [lL (A), and 4 °C and retained volume of 100 liL (0). Reprinted from Bai et al. (2007).

Step 1. Measure 1 to 4 L of a previously acidified water sample with a graduated cylinder and record the volume to the nearest 1 mL. (The laboratory instructor will specify the volume to be used for the experiment.) Filter the sample through a fluted filter paper and collect the sample in a clean beaker appropriate to the sample volume. [When analyzing a small sample volume,... 

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