V O L U M E 21, NO. 12, D E C E M B E R 1 9 4 9 Table 111. Results Obtained by Present and A.S.T.M. Distillation Methods Sample Calcium grease Sodium greaee Sodium grease Lithium grease
% Ha0. A.S.T.M. 0.8 1.0 None
Less than 0.1 Less than 0.1
% IIZO, Karl Fischer 0.91 0.92 0.038 0.040 0.098
1555 tent. Table I11 shows a comparison of results obtained on different greases by the present method and by the A.S.T.M. distillation method. ACCURACY
The method is accurate to 0.3 mg. of water, as shown by the data in Table 11, which are t,ypical results obtained from a large number of determinations.
0.100
0,099 0.103
stopcocks should not, be used in the direct path of the dist.illing vapors, as they will hold, by capillary action, part of t,he first water-rich distillate, and complete recovery of water will not, be accomplished. Although benzene was found to be a suitable solvent, for most subst,anres analyzed, it was difficult to disperse some greases in it, even on prolonged boiling. Greases were much easier t,o disperse in pyridine and formed a clear solution xith the boiling solvent. The pyridine-water azeotrope boils at. 96.7” C., and contains 43% water, and because water is miscible with pyridine, even large amount,s will remain dissolved in the distillate. In the analysis of greases difficulty with foaming was overcome by the addition of a few milligrams of an antifoam agent t o the pyridine prior to the initial dehydration. The commercially available DC Antifoam A was found to be excellent for this purpose. Table I1 shows the results of a series of samples of known water content. These samples were prepared by first dehydrating the solvent and sample as described in the procedure, cooling the mixture, and adding a weighed amount of water, either from a weighing pipet, or by adding more solvent of known water con-
LITERATURE CITED
(1) Aepli, 0. T., and McCarter, W. S.W., IND. ENG.CHEM., ANAL. ED.,17, 316 (1945). (2) Almy, E. G., Griffin, W. C., and Vilcox, C. S.,Ibid., 12, 392 (1940). (3) Am. SOC.T d n g Materials, Philadelphia, “A.S.T.M. Standards on Petroleum Products and Lubricants,” v . 60, 1947. (4) Benning, A. I?., Ebert, A. A . , and Irwin, C. F., ANALCHEM., 19, 867 (1947). (5) Evans, R. N., and Davenport, J. E., IND.ENG.CHEM.,ANAL. ED.,14, 732 (1942). (6) Foulk. C. W.. and Bawden, A . T., J . A m . Chem. Soc., 48, 2045 (1926). (7) Horsley, L. H., ANAL.CHEM., 19, 508 (1947). (8) International Critical Tables, Vol. 111, p. 389, New York, MrGraw-Hill ~ . - . - Book Co.. 1928. (9) Smith, D. My, Bryant, W. SI.D., and Mitchell, J . ,J.A m . Chem. Soc., 61, 2407 (1939). (10) Snyder, R. E., and Clark, 12. O., paper presented before Division of Analytical and Micro Chemistry, 112th Meeting of AM. CHEM.Soc., New York, N. Y., 1947. (11) Suter, H. R., r l s a ~CHEM., . 19, 326 (1947). (12) , , Weaver. E. R.. and Rilev. R.. Ibid.. 20. 216 (1948) (13) Wernimont, G’.,and Hopkinson, F’. J.; IND.‘ENG: CHEM., AN~L. ED., 15, 272 (1943). RECEIVEDApril 1, 1949. Presented before the Divisions of Petroleum Chemistry and Analytical and Micro Chemistry, Symposium on M i c r o chemistry and the Petroleum Industry, at the 115th Meeting of the AMERICAN CHEMICAL SOCIETY, San Francisco, Calif.
Report on Recommended Specifications for Microchemical Apparatus Carbon-Hydrogen, Dumas Nitrogen, Sulfur, and Halogen Committee for the Standardization of 3licrochemical Apparatus, Division of _AnalyticalChemistry, h l E R I C - i N CIIEYIIICAL SOCIETY i L STEYERMARK, Chairman, Hoffmann-LaRoche Znc., .l’utley, iV. J . 11. K. ALBER, Arthur H . Thomas Company, Philadelphia, Pa. V. i. ALUISE, Experiment Station, Hercules Powder C o m p a n y , Wilniington, Del. E. W. D. HUFFRIAR’, Huffman Microanalytical Laboratories, Denver, Cola .I. A . KUCK, College of t h e C i t y of .Yew Y o r k , New Y o r k , \. I-., and 4mericcin Cyanamid C o m p a n y , Stamford, Conn. .I. .J. MORAN, Iiimble Glass, Division Owens-Zllinois Glass Company, I inplnnil, V. J . C:. 0. WILLITS, Eastern Regional Research Luboratory, Philadelphia, Pa.
R
ECOhfMESDED specifications for microchemical apparatus t o be used in connection with the carbon-hydrogen, Dumas nitrogen, halogen, and sulfur determinations have been published by the Committee for the Standardization of Microchemical Apparatus, which was f i s t appointed in 1937 (5-7). At the 112th Meeting of the AMERICAS CHEMICAL SOCIETYheld in I $ - York ~ ~ ~in~September 1947, a by P. J. Elving, then chairman of the Division of Bnalytical and hiicro Chemistry, t o continue this work. This committee has declared its intentions to be as follows ( 1 ) :
1. Where needed, to revise apparatus rerommended by the
former Coninlit tee for t h e 8t:irict:irtlixiition of 1Iicrochsnlical .‘pparatus. 2. T o recommend specifications for other items of quant,itaive micro-, semimicro-, and ultr:tmicroRpparatus. .&iter this, field, attention will be given t,(, thr All recommendations will be made with t,he understanding that the specificat’ionsrepresent the best thought at the present time. Additional revisions will be made when necessary. Primary consideration be given to glass apparatus. The committee has held twelve meetings and has revieweti all of the previously recommended specifications. Changes are being presented for many items to increase efficiency, add
ANALYTICAL CHEMISTRY
1556 strength, and simplify the manufacture. Much experimental work waa done in the members’ laboratories before some of these ohanges were adopted. This report includes both the unchanged and the revised recommended specifications, so that all may be together for easy reference. Participation of chemists interested in microanalysis is invited by the committee. For this purpose questionnaires have been and will be circulated.
n
i
COMBUSTI
TUBE RECOMMENDATION 9
Carbon-Hydrogen (7). (OllOwiRg:
No changes have been made in the
Preheater (Figure 1) Constant-Temperature Chamber (Figure 2) Glass Parts for Pressure Regulator (Figure 5) Mariotte Bottle (Figure 6) Guard Tube (Figure 8) Platinum Boat (Figure 9)
GLAZE0
The following changes are recommended in the specifications for the absorption tubes (Figure 3), combustion tube with side arm (Figure 4), and bubble counter-U-tube (Figure 7).
ABSORFTIONTUBES(FIGURE3). The opening in the bottom of the stopper and that in the baffle have been increased from 0.25 * 0.05 mm. to 0.4 * 0.1 mm. to minimize the condensation of water a t these points. An additional tube of greater length is also recommended: a. Length of absorption chamber 80 mm. (over-all length 170 mm.) b (new). Length of absorption chamber 100 mm. (over-aIJ length 190 mm.) No markings or etching should appear on the tube. COMBUSTION TUBEWITH SIDE ARM (FIOURE4). The speciBcations remain unchanged except that all three ends are to be smooth and both the angle between the main part of the combustion tube a n i the .$de arm and the angle of bend of the side arm are now 90 * 5 BUBBLE COUNTER-U-TUBE(FIQURE 7). The diameter of the inner tube of the bubble counter has been increased from
.
-
GLAZE0
WALL I MM APPROX.
Figure 1. Preheater
Y to 10 mm. to 12 to 14 mm. in order to diminish backing upof the liquid in the bubble counter due to changes of prewure in the system and to minimize the effect of foaming of the liquid.
Dumas Nitrogen (6, 7). N o changes have been made in the recommended specifications of the following: Gasometer (Figure 10) Leveling Bulb for Use with Gasometer (Figure 11) Mercury Valve for Carbon Dioxide Generator for Use with Dry Ice (Figure 13) Combustion Tube with Tip (Figure 16)
-
380 400 MM.
16-18MM. OD. WALL 1.25- 1.50MM.
8-12 MM.
tcl
Figure 2.
Constant-Temperature Chamber
Although there are no changes in the recommended specifications for the mercury valve for the carbon dioxide generator for use with dry ice, the wording in parentheses describing the thread to take the 18-mm. cap has been changed from “Glass Container Association specifications” to “Glass Container Manufacturers’ Institute specifications.” PRECISION KITROMETER AND LEVELINQ BULB@ (FIGURE12). The top above the stopcock has been changed from a funnel shape to that of a cylinder of approximately 9.5-ml. capacity to prevent spillage. A minimum inside diameter of 2 mm. is specified for: ( a ) the capillar between the cylindrical top and the stopcock; ( b y the holes of the barrel of the stopcock; and (c) the top of the graduated tube The markings on the graduated portion are recommended to be placed on the left-hand side as shown in Figure 12 to make it possible to read the nitrometer when the combustion train isset upeither left to right (nitrometer on the right), or right to left (nitrometer on the left). Another modification is the addition of the socket of a spherical joint to the capillary side arm for connection to the stop. cock (or needle valve), This joint has been added to eliminate the use of rubber tubing. thuF
V O L U M E 21, NO. 12, D E C E M B E R 1 9 4 9
155P 0.25t 0 . 0 5 MM. I.D. 4 - 5 MM. LENGTH
-
0
-
1
Figure 3. Size
n
40-45 MM.
Absorption Tube
No markings or etchings on outaide Approx. Length Over-all Length for Absorbent, Rlm. with Stopper, M m . i B EO 170 * 5 100 190 + 5
5 t 0 . 5 MM. 0.0.
-1.5-2
Length of Body, M m .
C 135
155
5
*5
3.25f 0.25 MM. O.D.
11.25t 0.5 MM. O.D. 8f 0.25 MM. I.D. 1.5 MM. MIN. WALL
1.5-2 MM. 1.0.
MM. I.D.
MM.
END SQUARED AND GLAZED
Figure 4.
Combustion Tube with Side Arm 40-45
5f0.5MM, O.D.
1
15-2OMM.
GLAZED I
5f0.5 MM. O D o
I
i
1-2 MM. I.D.
GLAZED
210-220 MM.
I iI
c0.5 MM.0.D. WALL I MM. APPROX.
I I
3 WAY STOPCOCK 1,5 MM. BORE DIMENSIONS SAME AS FOR 5 1-1/2 STOPCOCK (EXCEPT BORES) APPROX.5 MM.
I REQUIRED
!I
I
I
-26-25 MMI QD. WALL 1.25 MM. APPROX.
I I
i
r
QGLAZED 2 REQUIRED
Figure 5.
1
210.220 M
I
I
1
Glass Parts for Pressure Regulator
i
15-50 -MM.O.D. JAU
!-3 MM.
3
3 REQUIRED
ANALYTICAL CHEMISTRY
1558 reducing the danger of breaking the side arm of the nitrometer. A corresponding change has been made in the Dumas stopcock (Figure 15). (The two parts of the spherical joint should be greased and securely held together by one of the mechanical clamps available for this purpose.) By virtue of the universal action of the spherical joint, alignment of these parts is unnecessary. Other niinor changes have been made: Length of calibrated portion Total length Dimensions of short side a m Note regarding lower part of reservoir Note regarding inside diameter of capillary at joint with reservoii A leveling bulb of the conventional type has been added The committee has no specifications for calibrating these micronitrometers, but suggests the following procedure in use by the National Bureau of Standards (2): The azotometer [nitrometer] is calibrated without the chamber, a t the 0.1, 0.3, 0.5, 0.8, 1.1, and 1.5 marks. After cleaning and drying, the cock is lubricated with a minimum of vaseline and the instrument is tared and then niounted in the inverted position with the cock closed. The theromometer is suspended beside it and a transparent screen is Dlaced around the asseniblv. , IS0 M M , f 10 MY. T6c mercury is put in a smdl glass reservoir provided with a stopcock and having a long slender delivery tube which is inserted into the tube of the azotometer [nitrometer] down to the cock. for the initial fillinr at the 0.1 'mark. MM. TIP OPENING Carefully run in the mercury, raihing the delivery stein as the
3-WAY STOPCOCK
2 MM. BORE OF PLU
7 MM.tO.5 MM. OB. WALL I MH. APPRO
5 MM: 0.0. APPROX. WALL I MM. APPROX.
2000 ML.
1
%SOLID
J
Figure 6.
Mariotte Bottle
STOPPERS
0 3.25 MM.t 0.25 MM. O.D. (FORM I ) 5 HM.tO.5 MY 0.0.
(FORM 2 )
3-4MM.0.D. GROUND AND BEVELED END TO BE 2-3MM. FROM BOTTOM OF BULB
Figure 7.
Rubble CounterU-'l'ubr
110-120 MM.
I 10-12 MM. OD. I MM. WALL (APPROX. )
filling progresses until the orifice is just above the surface. Fill nearly to the test mark, remove the stem, and by means of u long slender steel rod, probe around the filled portion of the azotometer [nitrometer] to work out air pockets. Insert the delivery stem nearly to the surface of the mercury and fill to slightly below the mark, agitate the tube to round the meniscus, and, if necessary, add or remove mercury to complete the setting on the line; or if preferred, simply observe the point a t which the meniscus stands, and correct accordingly. Round the meniscus for every reading. After observing the temperature, the azotomet,er [nitrometer] is allowed to stand for about 3 minutes, when the setting and temperature are checked, and, if satisfactory, the azotometer [nitrometer] is weighed. The azotometer [nitrometer] is again clamped in position arid after standing for 5 min-
1-1.5 MM. /OPENING
MM.
Figure 8.
Guard Tube
V O L U M E 21, NO. 12, D E C E M B E R 1 9 4 9 4MM.~
1559 Utes, the delivery stem is inserted, the filling is made to the next test mark, and the instrument is weighed as before. The same procedure is followed for the other points. Air pockets a t the cock seem to be the main source of trouble. In general practice, the actual volume above 50% KOH solution in contact with glass walls is accepted as being 0.001 ml. less than that found by the mercury calibration, based on a determination by the Physikalisch-Technischen Reichsanstalt. STANDARD KIPP GENERATOR, 2000 ML.(FIGURE14). The specifications for this apparatus have undergone several changes upon the recommendation of the sole American manufacturer.
Figure 9.
Platinum Boat
Weight 0.7 to 1.0 gram 3 . 5 % rhodium alloy
F i g u r e 11. Leveling Bulb 250 ml., for use with gasometer
The inside collar has a 50/12 joint, making possible the deletion of the descriptive phrase "ground to fit" in the old specifications and elimination of the diameter dimensions a t the lower end of the collar. The radius of curvature a t the intersection of the bottom and side wall of the body is now specified to be about 20 mm. to prevent sharp angles. There is a slight change in the over-all height of the body from 341 * 10 mm. to 356 * 10 mm. and also in the height of the constriction from 109 * 5 mm. to 124 * 5 mm. The outside surface of the side tubulature of the body is now glazed instead of ground. The diameters of the lower end of the stem of the funnel have been changed: the outside diameter from 14 * 2 to 18 * 3, the inside diameter from 11 * 1 to 7.5 mm. minimum. The distance from the lower end of the stem to the top of the ground zone has been changed from 310 * 5 mm. to 335 * 5 mm. D ~ N ASTOPCOCK S (FIGI.RE 15). After the publiration of the first specifications of the article (T), an error was detected in the drawing for the stoprock bore. Correction of this was made in a subsequent publication (6). Further modifications have been made to obtain greater strength as well as to include the ball member of a spherical joint for connection to the precision nitrometer (Figure 12).
IMPORT~NT: THE OD, OF LOWER 15 MM. LENGTH MUST
NOT EXCEED 19.5 MM.
Figure 12. Rlicronitrometer (Pregl Type) with Leveling Bulbs
ANALYTICAL CHEMISTRY
T~~~~ r 1 7 ? 2 MM.0.D.
.-t
SEE DUMAS STOPCOCK ( FIG. 15) EXCEPT OMIT LONG HANDLE
n
l o t 2 MM. O.D.
I
d 0 . 5 MM. O.D. WALL I MM. APPROX. OWED
1. MANUFACTURERS INSTITUTE SPECIFICATIONS )
Figure 13. hlercury Valve for Carbon Dioxide Generator for Use with Dry Ice
ALLMETAL NEEDLE VALVE (FIQURE 17). The committee has included the all-metal needle valve of the Hershberg-Southworth type ( 8 ) ,a new item, because of its general acceptance. Specifications are given in Figure 17. The side arm, although specified a t 140 mm., can be shortened, as desired, to fit a particular assembly. Connection of the side a r m th both the
combustion tube and the nitrorrieter may be made by nieaiiY of either heavy-walled rubber tubing or the proper ground joints. The ground joints may be cemented to the metal tube or connected by heavy-walled rubber tubing.
Sulfur and Halogen ( 5 ) . S o changps havr been made in the following:
ro TAKE NO. II RUBBER STOPPER t-51 M M . b MM. I.D.
,5 MM.
225 MM. O.D. ? I O MM. ID. NOT LESS THAN 45 MM. *PREFERABLY NOT LESS THAN 48 MM. TO ADMIT MARBLE CUBES 1-1/4" ON EDGE.
MM.22 MM. I.D. TO TAKE RUBBER STOPPER
.I1
18 MM.&
3 MM.
'
-
7
7- 112 MM. MIN. I.D.
263 MH.0.D. +,5 MM.
.
1
Porcelain Crucible (Figure 19) Glass Crucible Holder for Water Bath (Figure 20) Porcelain Filter Crucible and Ignition Dish (Figure "1)
Crucible Filter Assembly (Figure 22) Siohon. Receiver. and Inner Container for Barium 'Sulfate Filtration (Figure 23) Air Filter (Figure 27) Snipe Feather (Figure 30) Large-Size Glass Test Tube for Metal Microbomb (Figure 36) Changes have been made in the tollowing:
PORCELAIN FILTERSTICK(FIGURE18). This piece has been slightly changed with respect to the attachment of the filter plate. The length has been increased to about 55 mm. and the thickness of the filter plate has been specified as 2 mm. Tolerances have been established. GLASSDOME,METALCRUCIBLEDESICCATOR, AND UETALBLOCK(FIGURE24). Specifications are given for a new metal block to be used in connection with the glass dome and metal crucible desiccator. The block has the advantage of providing usable top and bottom surfaces, n-ith and without rim. It has been designed so that there will be a minimum of play Rhen transporting it in the metal crucible desiccator. With it, supported i t e m may be carried with greater safety.
-
Figure 14. Standard Kipp Generator (2000 Ml.)
V O L U M E 21, NO. 1 2 , D E C E M B E R 1 9 4 9
1561
7.5- 8.5 MM 0. THE DIRECTION OF
1.5 - 2 . 0 MM. I.D.
Figure 15. Dumas Stopcork
MICRO EVAPORATING DISHESFOR SULFURDETERMINATIOS WEIGHINGTUBE(FIGURE 28). For the sake of sturdiness the (FIGURE 25). These items have been made more sturdy by diameter of the rod has been increased to 2.5 t o 3 111111. and the specifying a wall thickness of 1.5 to 2.5 mm.
inside diameter of the sample receptacle has been increased to
PLATINUM MICROWARE FOR HALOGEN AND SULFUR DETERMI- 5 to 5.5 mm. (FIGURE 26). Tolerances are now included in the WEIGHING TUBEWITH CAP(FIGURE 29). The rod is specified
NATIONS
specifications of the crucible, Munroe crucible, and filter stick. The contact star has been revised completely ( 4 ) . The item made according to the old specifications was fragile and needed oonstant reshaping. The new item consists of a perforated outside cylinder into which has been spot-welded a heavier star to form a sturdy and serviceable platinum contact.
-r END SQU
to have a uniform diameter of 2.5 to 3 mm. for added strength. COMBUSTION TUBEWITH INXER SPIRAL(FIGURE 31). The tip is now specified to be flat with a slight bevel, ground, and polished. The solid spiral rod and center rod have been increased in size to 2.0 * 0.25 mm. diameter. FILTER TUBE(FIGTTRE32). The top of the filter tube haw been
ED AND ;LAZED
35 MM. I
--0 TO
530MM.
i; .-
-4
11.25 MM. O.D. & .5 MM. 8 .25 MM. I.D. 1.5MM. MIN. WALL
12 X 5 MM, RUBBER SLEEVE
NOTE: A 5 GROUND-GLASS JOINT CAN BE CEMENTED TO SOLDER THIS TIP. SEAL
