Potassium solution

Erlenmeyer et al. showed that it is possible to realize a moderated saponification of diethyl 4,5 thiazoledicarboxylate in mild conditions with an ethanolic potassium solution. The attack begins at the 5-position, and finally monoesters in the 4-position are obtained (Scheme 9) (17). 

For procedure (ii) the working standard solutions are prepared as detailed for procedure (i) except that the releasing agent solution is replaced by 10 mL of the stock potassium solution. 

Concentrated potassium solutions are for IV mixtures only and should never be used undiluted. Direct IV injection of potassium could result in sudden death. When potassium is given IV, it is always diluted in 500 to 1000 mL of an IV solution. The maximum recommended concentration of potassium is 80 mEq in 1000 mL of IV solution (although in acute emergency situations a higher concentration of potassium maybe required). 

Silk, W.K., Hsiao, T.C., Diedenhoffen, D. Matson, C. (1986). Spatial distribution of potassium, solutes, and their deposition rates in the growth zone of the primary corn root. Plant Physiology, 82, 853-8. 

Ambrus, A., Chen, D., Dai, J., Biabs, T., Jones, R.A. and Yang, D. (2006) Human telomeric sequence forms a hybrid-type intramolecular G-quadruplex structure with mixed parallel/antiparallel strands in potassium solution, Nucleic Acids Res., 34, 2723-2735. 

For example, the RI of water at 25 °C changes from 1.33262 to 1.3340 when 0.5 M K+ is present. For less concentrated metal solutions, the change in RI is less significant. Potassium solutions less than 0.1 M produced a change of less than 0.1% in the NA of the fiber.(65) This small change in the NA will produce only negligible changes in the detected fluorescence intensity. 

Typically, NIR optical fiber response times (/95%) for potassium solutions less than 5 x 10 M were less than 5.0 sec however, longer response times were observed as the concentration increased. For concentrations above a 1 x 10 3A7 K+,a typical t % was 1.25 min. The longer fluorescence response of the optical fiber detector at high metal concentrations is attributed to the thickness of the polymer matrix and the diffusion coefficient of potassium (10 10 cm2/sec). 

Concentrated Goncentrated potassium solutions are for IV admixtures only do not use undiluted. Direct injection may be instantaneously fatal. 

Ethylamine Solutions, (a) Photoregeneration of Bleached Solutions—The absorption spectra of alkali metals in ethylamine have been discussed in previous publications (24,25). Briefly, three characteristic bands are found, absorbing at about 650 (V), 850 (R) and 1300 (IR) m/z, and attributed respectively to metal monomers, dimers, and solvated electrons. In potassium solutions, the equilibria favor the V-band, while in rubidium the R-band is most prominent, except at extreme dilutions. 

Quite often Al, Fe, and Mg hydroxides partially fill the interlayer position of the derived vermiculites and decrease their exchange capacity and their ability to contract completely to 10 A when heated or when treated with a potassium solution. This material can usually be removed by treating the clay with a solution of sodium citrate (Tamura,1958). As the content of hydroxy interlayer material increases, the expandable clay tends to assume the character of a chlorite. Thus, in the weathering of a mica or illite it is not uncommon to form discrete vermiculite-like, beidellite-like, monf-morillonite-like and chlorite-like layers. These various layers can occur as discrete packets or interstratified in a wide variety of proportions. 

Much of the derived expanded clay, even that which resembles montmorillonite (holds two layers of ethylene glycol), will contract to 10 A when exposed to a potassium solution. Weaver (1958) has shown that these clays can obtain sufficient potassium from sea water and readily contract to 10 A. Vermiculite and mixed-layer biotite-vermiculites are rare in marine sedimentary rocks. Weaver (1958) was unable to find any expandable clays in marine sediments that would contract to 10 A when treated with potassium. A few continental shales contained expanded clays that would contract to 10A when saturated with potassium. Most vermiculites derived from micas and illites have high enough charge so that when deposited in sea water they extract potassium and eventually revert to micas and illites. Some layers may be weathered to such an extent that they do not have sufficient charge to afford contraction and mixed-layer illite-montmorillonites form. 

Fig. 4 Superfusion neurotransmitter release assay in synaptosomes. (a) Schematic drawing of a superfusion setup. Synaptosomes are preloaded with radioactive neurotransmitter and captured on fiberglass filters in superfusion chambers under continuous superfusion with gassed physiological salt solution (e.g., Krebs bicarbonate buffer) using a peristaltic pump. After a 10- to 15-minute wash, neurotransmitter release is triggered by rapid switching of superfusion lines to a stimulating buffer (e.g., high-potassium solution). Superfusate is collected on a fraction collector, and radioactivity is measured by liquid scintillation, (b) Typical trace recording of tritium-labeled norepinephrine fractional release in rat cortical synaptosomes stimulated by high potassium and a-latrotoxin in the presence or absence of external calcium.

All solutions were mixed by the first method and studied by means of gelation, light scattering and NMR experiments. Only potassium solutions (which seemed to be representative) were prepared by the second method of mixing and were studied by gelation and NMR experiments. 

The second method of mixing (for potassium solutions only) involved depolymerising the silicate species of the initial silicate solution, by the addition of alkali, throughout a series of experiments, and produced veiy different results, which do not lend themselves to the type of plot used in Figure 2. This is partly because, in many cases, the gel time is dramatically decreased. 

Working standard. Dilute the sodium/potassium solution fifty-fold with distilled water. 

L. van den Berg and D. Rose, The effect of freezing on the pH and composition of sodium and potassium solutions the reciprocal system KH2-P04-Na2HP04-H20, Arch. Biochem. Biophys. S7. 319-329 (1959). 

Only chemical interferences were observed sodium and potassium ionized in the air-acetylene flame, and aluminum ionized in the nitrous oxide-acetylene flame magnesium and calcium exhibited evidence of interference by both phosphorus and aluminum. All the other elements were found to be interference-free. The addition of 1000 ppm of cesium as an ionization suppressor effectively removed the ionization interference in the sodium and potassium solutions. Similarly, 1000 ppm of lanthanum removed the interference due to phosphorus and aluminum in the magnesium and calcium solutions and suppressed the ionization of aluminum. 

GIK, glucose-insulin-potassium solution AMI, acute myocardial infarction PTCA, percutaneous transluminal coronary angioplasty CABG, coronary artery bypass graft cariporide and enaporide are sodium/proton exchanger inhibitors N-acetyl-cysteine is an anti-oxidant agent. 

The replacement of potassium IV may be accomplished by way of IV piggyback or by buretrol. A pharmacist usually prepares the potassium IV piggyback, double checks the concentration and fluid, then dispenses the final product to the medical unit. However, with buretrol administration, essentially any clinician (e.g., nurse or physician) can prepare the solution on the medical unit, and infuse the potassium solution into the patient. 

In those secretory tissues where extracellular calcium is necessary for secretion, calcium enters by way of plasma membrane channels. Therefore, the nature of membrane channels is obviously very important. Are the channels uniform on a given cell Do their characteristics vary from tissue to tissue Many questions remain unanswered, but several studies suggest that a cell may have more than one type of calcium channel. Although not a secretory tissue, smooth muscle has two types of calcium channel potential sensitive channels and receptor operated channels (30). So, in this tissue [and probably in secretory tissues as well (31)], the nature of the stimulus may determine which channels are opened, the extent of calcium entry and the extent of the response. A high potassium solution, which is commonly used to activate calcium mediated responses, would open potential dependent channels whereas drugs acting on their respective receptors would open a different set of channels, but cause the same overall response. 

Ozone measurement Ozone reacts with the neutral potassium iodide solution and liberates iodine and in an excess of potassium iodide, iodine is in the complex triiodide form. The concentration of triiodide liberated was determined spectrophotometrically at a wavelength of 352 nm. By adding 5 mL of sample into a sample vial with 5 mL of 2% neutral potassium solution, a yellow colour was developed. After 30 minutes, measurement of the absorbance at 352 nm was compared with calibration curve to obtain the aqueous ozone concentration. 

---