Drying Pipets

Transfer the sample to an NMR sample tube using a dry pipet. 

When the top of the column runs dry, pipet carefully 300 pi liposome suspension onto the column wait until the top of the column runs dry and fill the column with HBS. 

To adhere cells to cover slips (1) Clean 22 x 30-mm U cover slips by dipping them in methanol and wiping with a Kimwipe. (2) Draw a circle off-center on each coverslip with a PAP pen (Ted Pella) and allow to dry. Pipet a 1% poly(lysine) (Sigma) solution into the PAP pen circle and leave for several minutes (the glass should wet readily if the solution beads up one solution is to first pipet a solution of 1% BSA or other protein onto the cover slip, remove this solution, rinse with water, and then add poly(lysine). Aspirate the solution wash twice with distilled water, and allow... 

Prepare a calcium stock solution (1000 mg L "1) by dissolving 2.497 g of dried calcium carbonate in a minimum volume of 1M hydrochloric acid about 50 mL will be required. When dissolution is complete, transfer the solution to a 1 L graduated flask and make up to the mark with de-ionised water. An intermediate calcium stock solution is prepared by pipetting 50 cm of the stock solution into a 1 L flask and making up to the mark with de-ionised water. 

Dry heat sterilisation is used for equipment that can withstand high temperature and dry heat but cannot withstand wet or steam autoclave. This method is often used for glassware as it dries and sterilises in one operation. The pipets must be wrapped in dustproof aluminum foil or placed in metal pipette cans. The can lids are removed during heating and replaced after sterilisation, that is before any dust can get in the can. Disposable items are not recommended for dry heat sterilisation. This method may only be good for permanent reusable glass pipettes. 

Fortifications are made by pipetting 100-500 o.L of the appropriate standards in acetonitrile on to the sample (10 g) before any extraction solution is added and then allowing the sample to air dry for 30 min. 

Jars containing the same amount of hand wash solution as used to collect the entire hand wash from the test volunteer should be fortified. The samples are fortified with the appropriate amount of active ingredient solution using a 1-mL volumetric pipet, blowing out the remaining solution in the pipet. The solutions are capped, shaken, and placed immediately in a freezer or dry-ice cooler. 

XANES to ensure the quality of the synthates. Three batches of ferrihydrite were synthesized and precipitates were washed 5-6 times to ensure a chloride-free synthate. Ferrihydrite precipitates were redispersed in 200 mL of double deionized (DDI) water at (1) room temperature (25°C), as well as preheated in water baths to temperatures of (2) 50°C and (3) 75°C. For all of these slurries, pH was kept constant at 10 using 1M KOH. 40 mL samples were pipetted from each reaction vessel after 0, 1,2, 3, and 7 days. Slurries were centrifuged, washed three times with DDI water and air dried for analyses (BET, XRD, and XANES). BET analyses were used to evaluate the decrease in surface areas with increasing crystallinity, and XRD and XANES were used to detail the structural and speciation changes in iron. 

B. l,3-Bis(methylthio)-2-methoxypropane. In a dry, 1-1., threenecked flask equipped with a mechanical stirrer, a 60-ml. pressureequalizing dropping funnel, and a thermometer is placed 13.8 g. (0.34 mole) of sodium hydride dispersed in mineral oil (Note 8). The mineral oil is removed by washing the dispersion with five 100-ml. portions of hexane (Note 9). The hexane is removed with a pipet after the sodium hydride has been allowed to settle (Note 10). 

In this method approximately 19 samples of marine sediment were oven dried at 110°C then digested with nitric acid-perchloric acid and hydrofluoric acid-hydrochloric acid. The digested solution is made up to 50ml of an equal volume mixture of 6M hydrochloric acid and 2M nitric acid. 0.1ml or less of the digest was pipetted into the hydride generator, followed by 1ml 2M acetic acid, diluted to 100ml with double distilled water and reacted with sodium borohydride. 

For each the calibration standard, unknown, control sample, and distilled water for the blank, pipet 50.00 mL into a clean, dry 125 mL Erlenmeyer flask. Add 8.0 mL of the combined reagent and mix thoroughly. After at least 10 min, but no more than 30 min, measure the absorbance of each at 880 nm. 

---