Reagents fresh

Sodium tetrahydroborate(lll) reagent - freshly prepare by dissolving 50 mg sodium tetrahydroborate(lll) per ml 3 M ammonia solution (0.1 ml reagent used per sample). Note original method used 100 mg mb concentration. 

At the end of the first tube s 10-min incubation, add 100 il freshly diluted 1 N Folin-Ciocalteu reagent (freshly diluted from a 2 N stock). Immediately vortex the tube for 2 to 3 sec. Continue to maintain the 15-sec intervals from step 3 for addition of the reagent to the remaining tubes. 

Amidol reagent—Dissolve, in order, 25 g of sodium bisulfite and 1 g of 2,4-diaminophenol in 100 ml of distilled water. Make this reagent fresh on the day that the assay is performed. 

Ammonium carbonate (concentrated). Shake 20 g ammonium carbonate, (NH4)2C03, with 80 ml water. Allow to stand overnight and filter. Prepare the reagent freshly. 

Tin(IV) chloride reagent (for removal of phosphate). Dissolve 5 g tin(IV) chloride, SnCl4, in 5 ml water. Prepare the reagent freshly. 

Reagent. Freshly prepared sodium hydroxide solution. 

CAUTION Fluorine and anhydrous HF can cause severe bums. Before undertaking work of the kind reported here, the experimentalist must become familiar with these reagents. Fresh tubes of calcium gluconate gel should always be on hand for the fast treatment of skin exposed to these reagents. 

Derivatization reagent for 10 samples mix 280 xl of ethanol, 40 xl of tri-ethylamine, 40 xl of PITC and 10 xl of 1.5 mM norleucine prepare the derivatization reagent fresh for each batch of samples and use the reagent within 2 h of preparation... 

A third fact is that a near-colloidal suspension of the reagent freshly formed has little activity, whereas the large particles several weeks later are very active. Alfin reagents made with mixtures of isopropoxide and... 

Procedure [151] Prepare the derivatization reagents fresh each day by dissolving OPT and the chiral thiol (10 mg each) in high purity methanol (1ml) and store at 4 C in the dark. 

Handling, Storage, and Precaution anhydrous conditions are required it is advisable to prepare the reagent freshly prior to use. 

Sulfomercurate reagent Freshly prepared mercury(II) sulfide (1.5-2 g) is added to 50 ml of 2 Af NaOH or KOH. A stream of hydrogen sulfide is passed through the suspension for 10 min. After warming, the excess mercury(II) sulfide is removed by filtration. The clear solution will keep for several days in a closed container. 

Reagent Freshly prepared alkaline hypobromite solution (8 ml bromine water plus 2 ml 5 iV sodium or potassium hydroxide, plus 2 g potassium bromide)... 

Spray with a soln. of glucose-85% phosphoric acid-water-ethanol-n-butanol (2g 10 ml 40 ml 30 ml 30 ml). Heat 5 rain at 150°C. Prepare reagent fresh daily... 

Hydrogen peroxide reagent. Dilute 25 cm of 20% v sulphuric acid solution and 4 ml 100 vol. hydrogen peroxide (Analar) to 100 cm with distilled water and shake. Allow to stand for 2 hours before use. Prepare this reagent fresh daily. 

Reagents fresh 1% sodium nitroprusside solution 2% sodium carbonate solution acetaldehyde (an aqueous solution is also suitable). 

Check the strength of this reagent, say> once a week, and prepare the diluted reagent freshly each day. 

---