Glass testing

The sodium fusion and extraction, if performed strictly in accordance with the above directions, should be safe operations. In crowded laboratories, however, additional safety may be obtained by employing the follow ing modification. Suspend the hard-glass test-tube by the rim through a hole in a piece of stout copper sheet (Fig. 69). Place 1 -2 pellets of sodium in the tube, and heat gently until the sodium melts. Then drop the organic compound, in small quantities at a time, down — =. the tube, allowing the reaction to subside after each addition before the next is made. (If the compound is liquid, allow two or three small drops to fall at intervals from a fine dropping-tube directly on to the molten sodium.) Then heat the complete mixture as before until no further reaction occurs. 

Reduction. Mix together intimately in a dry hard-glass test-tube o-i g. of... 

Action of heat. Heat about 0 2 g. of uric acid in a hard-glass test-tube. Note the charring and also the formation of a white sublimate on the cooler parts of the tube. 

Closed or open test eells. Open test eells are eonneeted to a seeond eontainment vessel. Test eells of various materials ean be used ineluding stainless steel, Hastelloy C276, and glass. Glass test eells of various sizes and shape are suitable for testing fine ehemieal and pharmaeeutieal produets/reaetion eonditions when the proeess is only in glass vessels or when only small samples are available, or if the samples are very expensive. 

The small glass test cell (10 ml) is useful when only small samples are available or if the sample is expensive. 

Reagier-kelch, m. test glass, test cup. -zylin-der, m. test tube. 

The mercury trap enables the operator to adjust the flow of the carbon dioxide according to the rate of absorption, and to apply a pressure of 45 mm. during the last half-hour. The pressure itself has practically no effect. The trap consists merely of a narrow glass test-tube containing mercury, and the tube is made to extend beneath the surface. 

Fig. 4.5.4 Heat stability of Periphylla luciferases A, B, C and L in 20 mM Tris-HC1 buffer (pH 7.8) containing 1 M NaCl and 0.05% BSA (solid lines) or 0.01% LCC (dotted lines). The buffer (1 ml) containing a luciferase sample was placed in a glass test tube that had been pre-equilibrated at a temperature in a water-bath. After 2 min, the test tube was briefly cooled in cold water, and then luciferase activity in 10 jl1 of the solution was measured in 3 ml of the pH 7.8 buffer containing 0.3 i,M coelenterazine at 24° C. From Shimomura et al., 2001.

Figure 8. Wetting cycles of crude oil SS1473/brine/glass tested in an anaerobic vessel. (Reproduced with permission from ref. 21. Copyright 1988 Society of Petroleum Engineers.)...

The amount of phthalate bound to the glass test tubes appears to be a function of the aqueous solubility of the phthalate. The solubilities of the phthalates have been reported to be 3.2 mg dibutyl phthalate and 1.2 mg bis (2-ethylhexyl) phthalate per litre of artificial seawater [70]. Table 1.10 shows that the more soluble dibutyl phthalate is absorbed far less than bis (2-ethylhexyl) phthalate. 

The amount of solute also appears to be altered by the presence of other material already on the surface. Between 70% and 80% of the total polychlorinated biphenyls stayed in the aqueous phase when bis (2-ethylhexyl) phthalate was not present. When approximately 400 ng bis (2-ethylhexyl) phthalate was absorbed to each test tube, only 55% of the total polychlorinated biphenyls stayed in the aqueous phase. The increased lipophilicity due to the presence of bis (2-ethylhexyl) phthalate apparently increased the adsorption of polychlorinated biphenyl by the glass test tubes. 

FIGURE 3.16. Schematic of the RSST Showing the Glass Test Cell and the Containment Vessel. 

Ciprofloxacin (Bayer Corporation) is often loaded at a D/L ratio of 0.3mol mol. After preparation of a ciprofloxacin standard solution (4mM in water), 5 pmol of lipid and 1.5 pmol of ciprofloxacin are pipetted into a glass test tube (or plastic Ependorf tube), adding saline to give a final volume of 1 mL (5 mM lipid concentration). This solution is incubated at 65°C for 30 minutes, with aliquots (50-100 pL) withdrawn at appropriate time points (0, 5, 15, and 30 minutes) and applied to a spin column [centrifuge at 2000 rpm (x670g) for two minutes]. An aliquot (50 pL) of the initial lipid-drug mixture is saved for determination of initial D/L. 

To perform the ciprofloxacin assay, a standard curve is prepared consisting of six glass test tubes containing 0, 50, 100, 150, 200, and 250 nmol ciprofloxacin (in water). The volume is made up to 1 mL with 200 mM NaOH. For the blank, ImL of 200 mM NaOH is used. Each LUV sample to be assayed should contain less than 250 nmol ciprofloxacin in a volume of 1 mL. 

Figure 3 (A) Robot system for lipofection screening (A) Worktable with racks for microplates, buffer reservoirs, plastic, and glass vials. (B) Four tip liquid handling arm. (C) Gripper for transport of microplates and glass test tubes. (D) High power water bath sonicator. ( ) Nitrogen evaporator. (F) Microplate washer. (G) Absorbance reader. (H) Luminescence reader. (/) Transparent hood. (/) CO2 incubator with pneumatic door (from the rear, front view in B). (B) Self-constructed robotic conveyor for the transport of cell culture plates from the incubator to the worktable.

Place 50 (xl of sample or cells in a 2 ml eppendorf or 13x100mm screw-capped, borosilicate glass test tubes with Teflon caps. 

Mendoza 50 mM carbonate, pH 8 None 100 pg/mL NHS, glass TEST PBS, casein... 

---