a sample is so low that the peaks are below the 

 center of the chart, the sensitivity should be 

 increased. Also, in areas where dissolved gas 

 content of sea water is extremely low, a larger 

 sample loop can be installed in the automatic 

 sampling valve to increase the quantity of gas 

 available in a sample. The Fisher-Hamilton Gas 

 Partitioner usually can be operated with the 

 sensitivity set at 8 (121/2 percent) except where 

 dissolved O2 content of sea water is low. 



Step 6. Set the recorder switch on Standby 

 and the chart-speed gearshift on li/^ or 2. 



Step 7. Adjust the line regulator valve (K) 

 until the He flow is 50 ml. per minute ±0.5 

 of a second, by depressing the detergent filled 

 bulb on the bubble counter burette (0) and by 

 measuring, with a stopwatch, the time it takes 

 a bubble to move 25 ml. in the burette. 



Step 8. Remove seioim cap from the oxygen 

 sample bottle, and place tube (G) deep in the 

 sample bottle. Turn automatic sampling valve 

 to Syphon position. 



Step 9. Start syphoning by depressing rubber 

 bulb (P). Turn on switch (Q) for 5 seconds to 

 activate vibrator, which insures complete filling 

 of the sample loop. Turn the automatic sam- 

 pling valve to Fill position when sample loop 

 is rinsed and filled ; then after 10 seconds, turn 

 the automatic sampling valve back to Syphon 

 position, and remove tube (G) from sample 

 bottle and wipe excess water from tube with lab 

 tissue. 



Step 10. Start chart paper by turning recorder 

 On switch to "Inches per minute," and set gas 

 partitioner sensitivity to 50 percent, or 8. 



Step 11. Annotate the strip chart with ship's 

 name, sample bottle number, and sensitivity 

 setting. 



Step 12. Adjust partitioner Balance (or 

 Coarse and Fine) until (green) pen is on line 

 of the chart paper (fig. J-15), and obsei-^^e the 

 pens to determine when sample results are re- 

 corded. Analysis of a sample usually requires 

 i to 5 minutes. 



J-23 Calculating the Oxygen and Nitrogen 

 Counts. — As the sample is analyzed, three sig- 

 nal peaks will be traced on the chart paper by 

 the signal (green) pen. The first is the compos- 

 ite peak, the second is the O2-A peak, and the 

 third is the N2 peak. While the signal pen traces 

 a peak, the integrator (red) pen produces a 

 separate but mathematically related curve. It 

 moves back and forth across the chart at a speed 

 proportional to the position of the signal pen, 

 i.e., as the signal pen moves away from the 

 line, the integrator pen moves faster. Therefore, 

 the integral curve developed is the total move- 

 ment of the integrator pen across the chart dur- 

 ing the time the signal peak is being recorded. 

 To arrive at the number defining the integral 

 of the recorded signal, read the displacement 



of the integrator (red) pen directly in chart 

 units or counts as follows (fig. J-15) : 



Step 1. With the signal (green) pen on and 

 the integrator (red) pen at its steady position 

 (anywhere between and 1.0 on the chromato- 

 gram) e.g., .580, watch for the sample results 

 to be recorded. 



Step 2. When the green pen starts to trace 

 a peak, the red pen moves across the chart paper. 

 Count the number of complete spans, or tra- 

 verses, the red pen makes across the chart, 

 e.g., 3.0. 



Step 3. When the green pen returns to the 

 zero line and the red pen is steady, read the end 

 position of the red pen, and compute the total 

 distance traversed on the chart paper, e.g., 



.580 + 3.0-f( 1.0 -.641) =3.939 



Step 4. Calculate total counts, e.g., 3.939 X 

 1000 = 3939 counts, and annotate the counts on 

 the strip chart (chromatogram), indicating 

 composite peak (COMP), Oxygen and Argon 

 peak (O2 + A), or nitrogen peak (N2), e.g., 

 3939 O2 + A. Enter the Oj + A peak and N2 

 peak counts in the appropriate column of Log 

 Sheet-CC. 



Step 5. When the sample has been analyzed, 

 open the toggle valve on tube (D), and drain 

 off as liquid waste about 3 centimeters of the 

 stripped sea water to allow space for the next 

 sample. 



Step 6. Repeat the above procedures for other 

 samples, and when all samples for the cast have 

 been analyzed, set the recorder in Stand-by 

 position, drain the sample chamber, and set the 

 four-way valve to By-pass, but do not change 

 the gas pressure. 



J-24 Determining the Gas Chromatography 

 Calibration Factor.— Before the O2 and N2 

 counts obtained during O2 sample analysis can 

 be converted to milliliters per liter, the gas 

 chromatography calibration factor must be 

 detennined for"0; and Nj. Calibration usually 

 is performed at the beginning, the middle, and 

 the end of a cruise to assure quality control of 

 data analysis. Figure J-16 presents a format for 

 setting up the calibration sheet. 



Step 1. Fill a 500-ml. capacity separatory 

 funnel with distilled water. 



Step 2. Purge the water with air from the 

 tank of air until it is saturated (about 15 min- 

 utes) . Use a glass purging tube. 



Step 3. Measure the temperature of the water 

 sample (Ti of HoO) to the nearest tenth C°. 



Step 4. Record the barometric pressure in 

 mm. of mercury. 



Step 5. Analyze several samples from the 

 purged solution to obtain an average. Record 

 sensitivity and average counts, and revert counts 

 to 100 percent. 



J-19 



