Centrifugal concentrator

The primary method for detecting methyl parathion and metabolites in biological tissues is gas chromatography (GC) coupled with electron capture (BCD), flame photometric (FPD), or flame ionization detection (FID). Sample preparation for methyl parathion analysis routinely involves extraction with an organic solvent (e g., acetone or benzene), centrifugation, concentration, and re suspension in a suitable solvent prior to GC analysis. For low concentrations of methyl parathion, further cleanup procedures, such as column chromatography on silica gel or Florisil are required. 

Blood, tissues Homogenize, if tissue mix sample with acetone centrifuge concentrate saturate with sodium chloride evaporate organic layer cleanup on silica gel eluting with hexane-benzene concentrate GC/FPD <100 ppb No data EPA1980d... 

Purify the biotin-dendrimer using size exclusion chromatography on a desalting matrix or by use of ultrafiltration (e.g., centrifugal concentrators). 

Concentrate the toxin to lOmg/ml using a centrifugal concentrator with a MW cutoff of 10,000. Retain this solution for the conjugation reaction. 

Concentrate the thiolated toxin to lOmg/ml using centrifugal concentrators. Immediately use the modified protein in the conjugation reaction to prevent inactivation of 2-iminothiolane-modified molecules by recyclization (Chapter 1, Section 4.1). 

Collect the peak containing the activated antibody (eluting first) and concentrate to 10 mg/ml using centrifugal concentrators. Use immediately for conjugating to a thiolated toxin. 

Concentrate the thiolated toxin to lOmg/ml using centrifugal concentrators. 

Immediately purify the MBS-activated toxin by gel filtration using a column of desalting resin. Apply no more sample than represents 5-8 percent of the gel volume. Isolate the protein peak by its absorbance at 280nm and concentrate to lOmg/ml using centrifugal concentrators with a MW cutoff of 10,000. 

Purify the reduced antibody using gel filtration on a column of Sephadex G-25. Concentrate the protein to lOmg/ml using centrifugal concentrators. 

Remove excess fluorophore from the labeled oligo using gel filtration on a desalting resin, dialysis, or a centrifugal concentrator. 

In general, a threefold dilution of the injected sample volume is to be expected. If necessary, the antibodies can be concentrated after this step. This can be conveniently accomplished using Centricon centrifuge concentrators (Amicon). 

All biochemical laboratory activities, whether in education, research, or industry, are replete with techniques that must be carried out almost on a daily basis. This chapter outlines the theoretical and practical aspects of some of these general and routine procedures, including use of buffers, pH and other electrodes, dialysis, membrane filtration, lyophilization, centrifugal concentration, and quantitative methods for protein and nucleic acid measurement. 

Concentrate the purified, SIAB-activated toxin to 10 mg/ml using centrifugal concentrators with a molecular weight cut-off of 10,000. Protect the activated toxin from light. 

Immediately purify the maleimide-activated avidin or streptavidin away from excess cross-linker and reaction by-products by gel filtration on a desalting column (Sephadex G-25 or the equivalent). Use 0.1 M sodium phosphate, 0.15 M NaCl, pH 7.2, as the chromatography buffer. Pool the fractions containing protein (the first peak eluting from the column). After elution, adjust the protein concentration to 10 mg/ml for the conjugation reaction (centrifugal concentrators work well for this step). At this point, the maleimide-activated avidin may be frozen and lyophilized to preserve its maleimide activity. The modified pro-... 

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