334 GASOMETRIC-VOLUMETRIC METHODS 



14. Remove from the water, dry by lightly wiping, taking care 

 not to handle the capillary, and read the gas vol. (V'l) in divisions. 



15. Fill the glass cup with pyrogallol soln. and absorb the oxygen 

 by pulling the gas down to the bottom of the capillary and back 

 again a few times. Finally move the gas bubble veiy slowly up to 

 the top part of the capillary. Equilibrate the temperature, and again 

 read the vol. (72) in divisions. When V2 is only a few divisions, 

 the second temperature equilibration may be omitted. 



16. Run a blank on the reagents by omitting the sample. 



17. Calculate the oxygen content from the formula: 



Oxygen = {\\ - V2 - C)f 



where C is the blank correction for oxygen in the reagents, and / is 

 the correction factor for temperature, aqueous vapor tension, and 

 barometric pressure. C amounts to 1.0 to 1.1 volume per cent at 

 room temperature as a rule ; / may be obtained from the usual tables 

 such as that given by Peters and Van Slyke (1932, page 129, Table 

 15). 



CARBON MONOXIDE 



Scholander and Roughton (1943a) described three applications 

 of the syringe analyzer to the measurement of carbon monoxide in 

 blood: a general method for saturation ranging from 0-100% car- 

 bon monoxide hemoglobin, a method for the measurement of both 

 oxygen and carbon monoxide on the same sample of blood, and a 

 method sufficiently precise for the determination of blood volume in 

 which the carbon monoxide level is held below 2 volume per cent. 

 Only the first of these three will be described. 



Scholander and Roughton Method for Carbon Monoxide 



SPECIAL REAGENTS 



Winkler Solution. Place 20 g. cuprous chloride, 25 g. ammonium 

 chloride, and 75 g. water in a bottle just large enough to contain 

 them. Stopper the bottle, shake with as little air as possible, and 

 allow the precipitate to settle. Put a coil of copper wire in the 

 soln. and cover the liquid with a layer of paraffin oil. The reagent 

 becomes almost colorless after a while. 



