Inorganic phosphate 



4/ 



Procedure: 



Reagents: 



1. Molybdic Acid - dissolve 12.5 gm. of 

 ammonium molybdate /(NH.) ,Mo-, 



°24 ' 4H 2 °_7 in 125 ml • di stilled water, 

 add 375 ml. 50% sulfuric acid, and 

 store in dark bottle . 



2. Stannous Chloride (SnCl .2H O) - dis- 

 solve 1 .2 gm. stannous cnlorrde in 5 ml. 

 cone . hydrochloric acid, and dilute to 

 50 ml. with distilled water (solution 

 made up daily) . 



Pipet 1 ml. samples into 10 ml. test tubes, 

 add 2 ml . distilled water and 3 ml . of reagent, 

 using automatic pipets. The reagent is care- 

 fully added by placing rack of test tubes on 

 approximately a 45° angle and allowing re- 

 agent to run down side of test tube to avoid 

 boiling. Mix contents by pouring gently from 

 the 10 ml. test tube to a 15 ml test tube and 

 back again. Store samples in darkness for 

 3-5 hours, transfer to 3 ml. micro cells, and 

 read densities using a green filter (525 mu) . 



Carbohydrates _' 



3 . Standard Stock Solution (2000 ,ug at PO 

 -P/L)- dissolve 0.2722 gm. of potas 

 sium di -hydrogen phosphate in distilled 

 water, and dilute to one liter . 



Procedure: 



Pipet 25 ml samples into 60 ml. flasks, 

 add 1 ml . of molybdic acid, and mix well by 

 swirling. Add 1 drop of stannous chloride _' 

 and swirl. Let stand from 20-30 minutes for 

 maximum color development, transfer to 23 

 ml. absorption cells, and read densities using 

 a red filter (650 m,u) . 



6/ 



Nitrate -nitrite _■ 



Reagents: 



1. 0.3 millimole Strychnidine/L - dissolve 

 0.0960 gm. strychnidine in one liter of 

 cone, sulfuric acid. 



2 . Standard Stock Solution (2000 ug at 

 N0 3 -N0 2 /L) - dissolve 0.1702 gm. 

 of sodium nitrate in distilled water, 

 and dilute to one liter. 



4/ Robinson, R.J. andT.S .Thompson, 1948. 



5/ Allow a lapse of 30-60 seconds between 

 additions of stannous chloride to samples 

 to ensure equal development time. 



6/ Marvin, K. T., 1955. 



Reagents : 



1. N-ethylcarbazole - dissolve 1 gm . of 

 recrystallized _' N-ethylcarbazole in 

 one liter of cone . sulfuric acid _' 

 (keep out of sunlight and store in re- 

 frigerator) . 



2 . Standard Stock Solution - dissolve 1 gm . 

 of L-arabinose in distilled water, and 

 dilute to one liter . 



7/ Collier, Albert, S.M. Ray, A.W.Magnitzky, 

 and Joe O. Bell, 1953. 



8/ Recrystallize N-ethylcarbazole as follows: 

 (1) dissolve about 50 gm. of N.E.C. in 500 

 ml. of warm alcohol, (2) add distilled water 

 slowly while swirling until precipitation is 

 complete, (3) collect precipitate on filter 

 paper, then add water to the filtrate and re- 

 filter, (4) redissolve precipitate collected 

 on filter paper in warm alcohol, (5) cool 

 alcohol solution in freezer to crystallize 

 N.E.C, (6) collect crystals on filter paper, 

 then salt out dissolved N.E.C. in filtrate 

 with water, (7) repeat steps 2-6 until fil- 

 trate is clear. Dry crystals at 50° C or 

 lower . 



9/ Use acid only from bottles that have a 

 plastic insert in screw cap. 



