AIDS FOR THE ANALYST

tempt has been made to devise a method of reasonableaccuracy which would require less time. Experiment I. Rectangles of 0.022-inch caliper bleached...
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Determination of Total Solids in Sulfate Pulp Mill Evaporator Feed Liquor. B. 13. Edmonds, Jr., The Chesapeake Corporation of \-irginia, \Yest Point, \-a.

approximately 1 to 1 mixture of S o . 10 motor oil and vaseline to the glass with a camel’s-hair brush. The article to be repaired is then presented to the flame in the usual Tvay and with reasonable care. By the time the grease has been burned away the glass will have reached the softening point and all danger of cracking \vi11 be past. The only failures experienced in the use of this procedure have been encountered in cases \\.here a crack started in an inner seal and extended into the inner tube where the grease could not be applied. One particularly gratifying use is found in the replacing of tips on burets where the break is within a half inch of the stopcock. “Ringing off” is prevented by the use of the grease and more rapid heating of the region to be repaired is permissible.



the determination of total solids by refluxing with xylene is less time-consuming than the overnight oven drying method, it requires upwards of 2 hours as performed in this laboratory. Kith the control laboratory primarily in mind, an attempt has been made to devise a method of reasonable accuracy which would require less time. LTHOCGH

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Experiment I. Rectangles of 0.022-inch caliper bleached blotting paper, cut to 2 X 4 inches, were dried in an oven maintained a t approximately 230” F., and cooled in a desiccator. One milliliter of sulfate pulp mill evaporator feed liquor was transferred to each of seven such blotters, which were returned to the oven. d t the end of 15 minutes the blotters were removed, cooled again in the desiccator, and rapidly weighed. The weight of the dry solids was calculated. The Baume of the liquor ]vas determined a t 80” F. and the weight of the sa,mpleread from a pipet calibration curve shown. Division of thc dry solids weight h y the weight of the sample, multiplied by 100, gave the per cent total solids Blotter

Total Solids r/ c’

1 2 3 4 5

15.4 15.9 15.2 15.4 15.6 15 6 15 2

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A Modified Atomizer for the Flame Photometer. Vincent Toscani, Russell Sage Institute of Pathology, S e w Tork, S. I-. need for rapid method for the quantitative estimatioii I of sodium and pot:issiuni has led to the development of the ’HP;

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Experiment 11. i\n analytical balance accurate to S= 1 mg. x a s placed on the o w n in such a manner that the left wtighing pan was suspended by a \\.ire which led through holes in the top of the o w n and the bottom of the balance case to the left arm of the balanrc. Thus thc steps involving cooling in the desiccator were ~ l i m i ntaed. Ten solutions of sulfate pulp mill evaporator feed liquor Jvere prepared, which ranged in specific gravity from 1.047 to 1.087. Total solids were determined on each solution by three different methods: \ 1) blotter method as described hut modified according to the p1,eceding paragraph; (2) refluxing with xylene; and (3) overnigiit oren drying. Specific> Grar-ity

1 1 1 1 1 1 1 1 1 1

04;

050 054 062 063 065 073 081 084 087

Blotter

9.5 10.3 11.2 12.1

13.0 13.5 14 8 16.2

16.9 17.1

P e r Cent T o t a l Solids Xylene

10 5 11.2 11.5 12.i

13.0 13.8 14.5 16.0 16.6 17.5

R

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flame photometer [Barnes, K . B., Richardson, D., Berry, J. IT., and Hood, R. L., ISD. ESG.CHEAI., ASAL. F;D., 17, 605 (1945)l. One of the difficulties encountered was the inability of the atomizer to produce a constant spray after several iveeks’ use. The internal surface of the metal needles became rusted and altered the characteristics of the spray. This necessitated the making of a neiv atomizer unit after a short period of time. To overcome this trouble a neiv atomizer was constructed of &a as shown in Figure 1. The unit I W ride ~ by E. II:ichl?tt R: $(in, Serr l-ork.

C

Oven

9.4 10.6 11.2 12.3 13.0 13.4 14.9 16.4 17.0 17.6

I

0.014”CAI?

Figure 1

Preventing Extension of Cracks in‘ Repairing Glass Apparatus. Ernest R. Kline, Department of Chemistry, Cniversity of Connecticut, Storrs, Conn.

MOST glass bloiver.: are aware that moistening a file scr.it:h facilitates breaking a length of glass tubing. The moistening agent may be either water or saliva and the exact nature of the action is obscure. The aut,hor has observed that unless the finger with irhich the saliva or water is applied is free from grease, the scratch d l become more resistant to fracture upon application of pressure. It seemed logical that this operation could be used in reverse to check the extension of a crack or t o prevent its starting. The procedure used in this laboratory congists of applying an

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Flask A is the medium thi,ough which the spray from the atomizer is carried to the burner, EC is a capillary tube of 0.014-inch bore through which the unknown solution is fed. D is a capillary tube of 0.10-inch bore drawn to a tip having a bore of 0.014 inch. C and D are joined together with two solid glass rods. The disinch. tance between the two capillaries is The all-glass atomizer has the folloxl-ingadvantages: The glass unit can be easily duplicated, the spray is alLvays constant,, and in case of clogging of the capillaries, another unit can be quickly substituted while the clogged unit is being cleared in cleaning solution. The atomizer operates efficiently using 10 pounds air pressure, while a pressure of 2.5 pounds is used for the burner gas. Several all-met,al atomizers manufactured by the Spraying Systems Co. of Chicago have been used by other’laboratories and appear to work satisfactorily.