Humidity buffers

Stable in water), so we need a way of controlling /g o i range of, say, 25-100 °C. A convenient way to do this is with the humidity buffer technique. Consider, for example, the calcanthite-bonattite reaction, which is... 

AMP is used as an emulsifier and a buffering agent. It controls the water solubility of the resin film in hairsprays, and makes the finished film more resistant to humidity. 

The emulsifier aminomethyl propanol serves several purposes in hairspray. It acts as a buffering agent, controlling the acidity of the mixture to make it neutral ( pH balanced ). It also helps keep the polymers mixed with the water and alcohol, and controls the water solubility of the final mist, giving it the needed humidity resistance. It also helps to form the polymers into a gel. 

McQuain M.K., Seale K., Peck J., Levy S., Haselton F.R., Effects of relative humidity and buffer additives on the contact printing of microarrays by quill pins, Anal Biochem. 2003 320 281-291. 

Surface Water. Crossland and Wolff (1985) reported that the phototransformation half-life of pentachlorophenol in surface water ranged from 1.5 to 3.0 d. In a laboratory experiment, the average volatilization half-life of pentachlorophenol in a stirred water vessel (outer dimensions 22 x 10 x 21 cm) at 23 °C and an air flow rate of 0.20 m/sec is 624 min. The half-life was independent of wind velocity <1 m/sec or air humidity but very dependent upon temperature. Given that pentachlorophenol is a moderately strong acid, the experiments were repeated using four different buffered solutions. The average half-lives were 151 h at pH 4.0, 167 h at pH 3.3, 303 h at pH 5.1, and 3,120 h at pH 6.0At pH. No volatilization was observed at pH 8.0 (Klopffer et al., 1982). 

Remove coverslip and blot excess buffer from sample, taking care not to directly touch sample. Add enough TdT labeling reaction buffer to cover sample. Cover with plastic coverslip and incubate in humid chamber for at least 60 min at 37°C. Stop labeling reaction by removing coverslip and washing sample in 2X SSC for 10 min at room temperature. 

McQuain et al. (2003) undertook a detailed study on the effects of relative humidity and a direct comparison of fhe impacts DMSO vs. betaine in print buffer on the overall performance of quill pin printing. A video microscope was employed to visualize and track the drying behaviors of the various printing inks. A Cy5-labeled 466-bp dsDNA probe was used to monitor the printing process. Drop-drying behavior, bulk evaporation from the quill reservoir, surface tension changes, and spothng characteristics (spot diameter, spread, and number deposited) were examined at different RH levels. 

Figure 4.35 Spot variation upon printing in various buffers at different relative humidities. (From McQuain, M.K. et al.. Anal. Biochem., 320, 281-291, 2003. With permission.)...

For a dual BISH assay with two AP-based detections, incubate the entire tissue section with hybridization buffer for 30 min in a humidity chamber/box at room temperature. 

Method. The organothiophosphorus insecticides are separated on silica gel with hexane-acetone (2 1 or 3 1). The plate is dried in air and sprayed with a solution of calcein-palladium chloride (0.0005 M palladium chloride in 0.1 M hydrochloric acid mixed with an equal volume of 10-3 Af calcein, adjusted to pH 7.2 with phosphate buffer and diluted with water to obtain a 2.0 10 4Af solution of palladium equilibrated overnight) which is diluted 1 1 with a 50% solution of acetone—water. When the plate is translucent it is dried in air and stored for 18—24 h in a closed chromatographic tank containing a beaker of a saturated solution of calcium nitrate tetrahydrate. This procedure permits the full fluorescence to develop under controlled humidity. The plate is then observed under a UV light at 365 nm, or scanned quantitatively at 365 nm (excitation) and 518 nm (emission). 

The sections are incubated in a primary antibody (diluted appropriately) for 72 hr at 4°C in a sealed humid chamber the incubation is carried out by applying droplets of the antibody to the sections. After being rinsed in the buffer, the sections are incubated for 90min in secondary antiserum diluted 1 50 with PBX (0.3% Triton X-100, 0.01% sodium azide and 0.1 M phosphate buffer) and then treated for 1 hr under agitation in peroxidase-antiperoxidase (PAP), diluted 1 100 with PBX, in a sealed humid chamber in both cases. 

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