crystals are obtained. Dissolve 1 gm. 

 of the crystals in 1 liter of Du Pont 

 c. p. H2SO4, and transfer to amber- 

 glass automatic acid burettes to pro- 

 tect it from the light. 



"Protein" 

 (Tyrosine equivalent) 



We used the Z. P. Zein-Eldin and B. Z. 

 May (unpublished manuscript) modification 

 of the P. J. Wangersky method (Collier e_t al . 

 1958) for the determination of protein 

 (tyrosine equivalent). 



The determination is carried out as 

 follows : 



1. Thaw frozen samples. When sample 

 has attained room temperature, clean cap- 

 glass junction with a jet of distilled water. 



2. Pipette duplicate 200-mill iliter 

 samples into 50-milliliter glass reagent 

 bottles that have ground-glass stoppers. 



3. Add 20 ml. of 0.75N NaOH from an 

 automatic burette. 



4. Autoclave at 80 lbs. for 2-3 hours. 



5. Centrifuge until clear. 



6. Read on the Beckman DU spectro- 

 photometer, using the optical density scale. 

 Set wave length at 330 m)x and use the ultra- 

 violet light source. Using the 5-centimeter 

 silica cells, read against distilled water. 



7. Treat blanks and samples of tyro- 

 sine (1, 3, 5, mg. per liter) similarly. 

 Prepare blanks from Brujewicz' artificial 

 sea water (Sverdrup, Johnson, and Fleming 

 1942): 



Triple-distilled 

 water - to 1,000 gm. 



WASHING PROCEDURES FOR ALL 

 ANALYTICAL GLASSWARE 



We recommend the following procedure 

 for use in routine analyses: 



Glassware for all determinations ex- 

 cept nitrite, copper, carbohydrate, protein, 

 and salinity should be treated as follows: 



Immediately following use, rinse all 

 glassware and fill with distilled water 

 until it is to be washed. Wash with 

 10-minute immersion in dichromate-sulf uric 

 acid cleaning solution. Then rinse succes- 

 sively with tap and single-distilled water, 

 followed by three rinses with triple- 

 distilled water. If not used immediately, 

 rerinse with triple-distilled water just 

 prior to use. 



Nitrate-nitrite tubes — rinse these in 

 distilled water and then place in technical 

 grade H2SO4. Prior to use, rinse the tubes 

 with triple-distilled water as mentioned in 

 the general procedure. 



Salinity bottles — pour out any remain- 

 ing sample. Rinse bottles with distilled 

 water, and then fill with about 50 ml. of 

 distilled water. 



Copper bottles — rinse these in dis- 

 tilled water and dip in a 5-percent hydro- 

 fluoric acid solution for cleaning. The 

 rinsing procedure is the same as that given 

 above . 



Carbohydrate flasks — do not use tap 

 water. After use, rinse the flasks with 

 distilled water and immerse overnight in 

 Du Pont c. p. H2SO4. Before reusing, rinse 

 once in single-distilled and three times in 

 triple-distilled water and allow to dry. 

 If clean flasks are not used within a week, 

 reimmerse them in acid before use. 



Protein bottles — place these directly 

 into a hot detergent solution (Alconox) for 

 at least 24 hours. Rinse these bottles, 

 dip in a 5-percent hydrofluoric acid solu- 

 tion and rerinse as above. 



Before use, leach all new glassware 

 at least 12 hours with 10-percent H2SO4 in 

 an autoclave at 30-40 pounds steam pres- 

 sure. 



12 



