Kaolin, light, R

Kaolin as described in the monograph for Kaolin.

Kaolin suspension TS

Procedure. Immediately before use mix equal volumes of cephalin TS and a suspension containing 4 g of kaolin R in 1000 mL of sodium chloride (9 g/L) TS.

Karl Fischer reagent TS

A freshly prepared solution contains up to 5.0 mg/mL of water. The solution should not be used if the water equivalent falls below 2.5 mg of water per mL of the reagent.

Procedure. Dissolve 63 g of iodine R in 100 mL of anhydrous pyridine R, cool in ice and pass sulfur dioxide R into the solution until a gain in weight of 32 g has occurred, taking care to avoid absorption of atmospheric moisture. Add sufficient dehydrated methanol R to produce 500 mL and allow to stand for 24 hours. Karl Fischer reagent TS may also be prepared by mixing commercially available solutions of sulfur dioxide in pyridine and of iodine in methanol, which are stable when properly stored, for example, protected from light. The resulting solution should conform to the requirements stated below.

Method of standardization. Ascertain the exact content of water in the following manner: add about 20 mL of dehydrated methanol R to the titration vessel and titrate to the end-point with Karl Fischer reagent TS without recording the volume required. Introduce in an appropriate form a suitable amount of water, accurately weighed, and titrate again to the end-point with Karl Fischer reagent TS, recording the volume. Water might be introduced, for example, as a solution in dry methanol or under the form of a hydrated compound. Calculate the water equivalent of the reagent in mg of water per mL. Karl Fischer reagent TS deteriorates continuously and should be standardized immediately before use or daily as required.

Note: Ethylene glycol monoethyl ether R may be used in the preparation of the reagent instead of dehydrated methanol R.

Kieselguhr R1

Kieselguhr G

Description. A greyish-white powder of an average particle size between 10 and 40 μm, containing per kg about 150 g of calcium sulfate, hemihydrate.

Kieselguhr R2

Kieselguhr GF254

Description. A greyish-white powder of an average particle size between 10 and 40 μm, containing per kg about 150 g of calcium sulfate, hemihydrate and an adequate amount (usually about 15 g/kg) of a fluorescent indicator having a maximum absorption at 254 nm.

Kieselguhr R3

Description. A greyish-white powder of an average particle size between 170 and 200 μm.

Kieselguhr R4

Description. A greyish-white powder of an average particle size between 70 and 150 μm.

Kieselguhr R5

Kieselguhr H

Description. A fine, greyish-white powder; the grey colour becomes more pronounced on triturating the powder with water. The average particle size is between 10 and 40 μm.