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The determination of iodide‐iodate activity in sodium radio‐iodide (I131) by automatic scanning of paper chromatograms
SCIENTIFIC EDITION
February, 1955
of 80.4 per cent, based on the starting compound, C14labeled barium carbonate. REFERENCES (1) Pijoan, M.. Gujovich. H. J., and Hopwood, M Y.,
u.(gj
%&:$:;
107
~~~;ff;.7f";d5"89,"1f~!).
(3) Dauben, W. G . , Reid, J. C . . and Yankewich. P. E., Anal. Chem.. 19, 828(1947). (4) Gilman, H., Zoellner, E. A,, and Kickey, J. B . , J . A m . Chem. SOC.,51, 1576(1929). (5) Hkkinbottom, W. J., "Reactions of Organic Compounds, Longmans, Green and Co., New Ynrk, 1948, p. 242.
The Determination of Iodide-Iodate Activity in Sodium Radio-Iodide (I131)by Automatic Scanning of Paper Chromatograms * By JOHN J. PINAJIAN and JOHN E. CHRISTIAN RJ values of different width filter paper chromatograms using 7 5 per cent methanol
in a n ascending system are presented for iodide and iodate. The chemical identity of the spots is determined by the use of carrier iodide and iodate. T h e iodide spot was developed by spraying the dry chromatogram with starch hydro e n peroxide solution. The iodate spot was developed with a spray of ascorbic aciff-starch solution. Description of the equi ment is given. T h e relationship of the chart drive s eed and the optimal slit wi& to the time constant of the countin rate meter is 8scussed and the minimal slit width calculated for the instrument u s e k Integration of the curves gave areas representing the total activity at each spot. T h e ratio of the iodide-iodate activities thus determined differed from the relative readings of the counting rate meter. mm., and 20 mm. were used). The spots were air dried and a drop of carrier solution (using a standard dropper) was then spotted at the same site. The carrier solution contained 1.66 mg. potassium iodide, 2.14 mg. potassium iodate, and 10 mg. sodium bicarbonate per ml. The paper was air dried and a small strip of tin foil was folded over the bottom as a weight. 'A 250-ml. ground-glass stoppered graduated cylinder was used for the chamber. Methanol, 25 ml. of 75 per cent,2was pipetted into the bottom and the strip was hung so that one-half inch of the tin foil weighted bottom was immersed in the solvent. The ground glass stopper held the paper in place. The chromatogram was allowed t o develop for four hours ddring which time the solvent front traveled approximately 30 cm. The strip was withdrawn from the cylinder, the solvent front marked immediately, and the strip allowed to air dry. Chemical Identification of the Spots.-The spots on the filter paper chromatograms were chemically identified by spraying the paper with a fine spray of Starch Test Solution, U. S. P. XIV, spraying with Hydrogen Peroxide Solution, U. S. P. XIV, and finally spraying with ascorbic acid solution, 5 per cent. The sprays were applied with a DeVilbiss EXPERIMENTAL No. 251 atomizer. The ascorbic acid solution was prepared fresh each month. Paper Chromatography.-A finely drawn capillary The spray of starch and hydrogen peroxide gave a was inserted into the Sodium Radio-Iodide (IlS1)l rapid (less than one minute) response (brown color) and approximately one lambda was allowed t o be with the iodide spot, while the iodate spot remained drawn up by capillary action. This was then unaffected. With the addition of ascorbic acid, the spotted one inch from the bottom of 18-inch strips iodate was reduced promptly (less than one minute) of Whatman No. 1 filter paper (widths of 8 mm., 10 t o give a purple color changing t o brown within two * Received August 28, 1954, from the Bio-Nucleonics minutes. The spraying of starch-iodide impregnated paper Laboratory. School of Pharmacy, Purdue University. West Lafavette. Ind. with ascorbic acid gave negative rcsults, cvcti after
of an investigation concerning t h e assay of Sodium Radio-Iodide (1131) used for medicinal purposes,' it became necessary t o distinguish between the iodide and iodate forms of the activity present. Since the amount of material present for analysis represented something in t h e order of 10-l2 Gm. ordinary techniques of differentiation were not suitable. The technique of paper chromatography appeared t o be the most suitable and the most convenient instrument readily availablefor the resolution of the two forms of 1131 activity. Indeed, once separated, the very nature of the iodide or iodate prese n t allows for a fairly accurate estimation of the relative ainourits present. T h e common practice of utilizing autoradiographic procedures with subseyuen t visual or densitometric determination of the amount of fogging was not suitable because of t h e time factor involved. Various direct methods of scanning have been described (2-7). N THE COURSE
I
hksented to the Scientific Section of A. PB. A.. Boston, meeting, August, 1954. 1 Obtained frnm the Oak Ridge National Laboratory, Oak Ridge, Tenn.
* The solvent system used here was first suggestcd Iiy Gleason (8), Abbott Lahoratories, Oak Ridge, Tenn.
108
JOURNAL OF THE
AMERICAN PHARMACSUTICAL ASSOCIATION
Fig., 1.-Recording of the iodide and iodate activities of a filter paper chromatogram of sodium iodide ~ 1 3 9 . (The lower most marking locates the spotting site and the upper most marking locates the solvent front line.) one hour. The addition of hydrogen peroxide to the iodate spot after treatment with starch spray similarly gave negative results. Radioactivity Assay of the Chromatograms.-For determining the activities of the iodide and iodate spots, the strips were pasted along the cdgc of a section of chart paper (Esterline-Angus Chart 4309-C), allowing alternating 30-cm. sections of clear chart paper in between. The chart paper was then rolled on t o the spindle of a 1-ma. EsterlineAngus recorder. Small weights were clipped on the end of the chart paper. The chart paper was arranged so that the chromatogram passed in front of a thin slit of a brass plate which shielded the Geiger-Muller c o ~ n t e r . ~ Constant geotpetry was maintained by placing a lead block in back of the chart paper. The pulses from the Geiger-Muller 8 End-window Geiger-Mliller counter wit11 a 2.3-mg./cin.' mica window.
Vol. XLIV, No. 2
tube were fed to a counting rate meter' and from there to the recorder. As the paper chromatogram spotting line passed a line a t the middle of the slit, the pen was manually moved across the chart t o give a spotting line on the chart. Similarly, as the solvent front line moved across the marker, another line was made on the chart. With the arrangement described, specification as to the chart drive speed and the optimal slit width is dependent upon the time constant of the counting rate meter. The value for the time constant varies in different circuits and sensitivities from one second to about one minute and is minimal for the highest counting rate sensitivity in a given circuit. Thus, it is advantageous t o work whenever possible with a high level of activity in order t o minimize the time constant of the rate meter response.6 When this is done, the practical limiting factors are the chart drive speed and the slit width. With a chart drive speed of 28 cm./hr., the minimal slit width was calculated t o be 3.4 mm. The slit width was machined t o 5.0 mm. and was made 20 mm. across to accommodate various widths of filter paper strips. The R , values obtained under the conditions described were 0.76 f 5% and 0.45 f 5% for iodide and iodate, respectively, and were in correspondence with R, values determined by the conventional method. The method described has the advantage of presenting well-defined peaks which represent the centers of density. Thus the uncertainty of the R, value is considerably reduced by simple measurement of well-defined distances. A sample recording is reproduced in Fig. 1. A planimeter was used t o measure the area beneath the curves. This area represents the total number of counts in the spot. The background was subtracted by extending the horizontal base line. The distribution of the radioactivity between the iodide and iodate spots in the sample recording illustrated above was found t o be 93.6 and 6.4% for iodide and iodate, respectively. The distribution as calculated from the relative readings of the counting rate meter was found t o be 92.4 and 7.6% for iodide and iodate, respectively.
SUMMARY
A simple automatic scanning and recording device has been described for the paper chromatography. T h e relationship of the chart drive speed and the optimal slit width t o the time constant of the counting rate meter has been discussed and the minimal slit width has been calculated for the instrument used. R,values of radioiodide filter paper chromatograms have been presented. A method for determining the ratio of t h e iodide-iodate activities present have been described. A method for the chemical identifica4 Model 1615, Radiation Sentinel, Nuclear Instrument and Chemical Corp., Chicago. Ill. 6 One should nut, of course, count at such a rate that resolving time corrections become necessary. For example, with the full-scale response of the counting rate meter set a t 5000 c. p. m. and the resolving time of the Geiger-Miiller counter 200 p sec., the correction for losses at the maximnm rate will be aoDroximatelv 1.68 Per cent. Since the countinn rate varies from zero thkough 'the maximum t o zero for given spot, the resolving time error in the estimation of the activity of the spot will be less than 1.68 per cent.
a
SCIENTIFIC EDITION
February, 1955
tion of the iodide and iodate spots on t h e paper chromatograms has been developed.
REFERENCES (1) Miller L. C . Drug Sfandards 22 168 1954). (2) Mulle;, R. H., and Wise, E. N . , ’ A n J . Chcm.. 23, 207 (1951).
109
(3) Jones. A. R., ibid., 24, 1055(1952). (4) Williams, R. R . , and Smith, R. E,, Proc. SOC.Expfl. Biol. M c d . , 77, 169(1951). (5) Rockland L. B. Lieberman, J., and Dunn, M . S., Anal. Chcm. 24 ’778(1962). (6 Wintkin ham, F. P. W., Harrison, A., and Bridges, R. Analyst,%7. lQ(1952). (7)’Frierson, W. J., and Jones,J. W.. Anal. Chem., 23,1447 (1951). (8) Gleason, G. I., Personal communication.
d.
Properties and Applications of Powdered Polysaccharide Acids* I.
Preparation and Titration Curves
By JOSEPH V. SWINTOSKY,t LLOYD KENNON,$ and JAMES TINGSTAD Several new powdered polysaccharide acids, namely elm acid, quince acid, and plantag0 acid, were prepared by ion exchange, followed by spray drying. These acids, carboxymethylcellulose acid and several analogous type acids were titrated potentiometrically, and the shape of the titration curves were indicated to be quite typical of the synthetic cation exchangers. Approximate acid equivalents and pKa values-were determined for some of these substances. A number of pharmaceutical applications for these acids are suggested.
RIDOUThave described the use of powdered alginic acid as a tablet disintegrant (1) and we have similarly noted a n d reported this property (2) for the spray-dried powdered acid form of carboxyrnethylcellulose (HCMC). Some recent publications have also described the cation exchange properties of alginic acid (3, 4, 5) a n d chemically modified cotton fabrics (6). T h u s a number of the naturally occurring gums and related products possess the chemical structural requirements for ion exchange. Possible uses already discovered for some of the polysaccharide acids, coupled with other chemical a n d physical features, suggested a program embracing their preparation a n d an investigation of their pharmaceutical applications. ERRY AND
EXPERIMENTAL Materials.-The polysaccharide acids employed in this study were derived from algin, sodium carboxymethylcellulose, linseed, elm, quince, acacia, and plantago seed. Alginic acid employed in this study was Ke1acida.l The powdered linseed acid and the arabic acid were prepared by ion exchange and spray drying in these laboratories, and have been previously described (2, 7). Powdered HCMC has also been prepared (2); but for this study, a slight modification of the previous method of preparation was followed. Preparation of Elm Acid Solution.-Approximately 2.3 Kg. of elm bark* was used. Ten I,. of Received April 22, 1954, from the School of Pharmacy, University of Wisconsin, Mahson. Supported in part by the Research Committee of the Graduate School from funds supplied by the Wisconsin Alumni Research Foundation 7 Present Address: Smith, Kline & French LaboratorieP, Philadelphia 1 Pa. $ Fellow, Akerican Foundation fer Pharmaceutical Education 1 Kelco Co..Chicago, Ill. 2 Elm bark, quince seed, and plantago seed were obtained from S . B. Penick Co.,N. Y.
boiling distilled water was poured over the bark contained in a porcelain pan. The water was allowed t o cool t o room temperature, and the mucilaginous layers formed on the bark surfaces were dispersed into the water by rubbing. The rubbing process was repeated after two hours of maceration. The liquid infusion was then separated from the bark. The bark was again subjected t o the steeping process. About 20 L. of an orange-brown mucilaginous infusion of elm bark was obtained. The infusion was saturated with chlorobutanol to inhibit fermentation and was then strained through two layers of muslin. The mucilaginous polysaccharide was precipitated from solution by pouring 60 L. of alcohol, into the 20 L. of infusion. It appeared as a white fluffy substance somewhat like paper pulp and was collected by filtration through muslin. It was then expressed free of liquid by squeezing in the hands; the material became light ash colored. In 150 cc. of alcohol it assumed a very friable character and crumbled into small particles upon stirring. Distilled water was added in small increments with stirring t o permit uniform wetting and hydration of the product. When a total volume of 1 L. was attained, the product, a thick homogeneous mucilage, was poured with stirring into 1 L. of boiling distilled water. After further swelling, it was diluted with warm distilled water to a total volume of 8 L.and after standing several hours, 24 L. of alcohol were added to reprecipitate the polysaccharide. The precipitate was filtered through muslin and redissolved in water to a volume of 20 L. The series of alcohol precipitations were performed to separate the polysaccharide gum from the other principal extractive materials of the bark. T o obtain the elm acid solution, the viscous gum solution, maintained a t about 50-60°, was passed through a series of eight 4-L. flasks, each flask containing about 500 Gin. of acid charged 1R-120 cation exchange resin.3 About fifteen to twenty minutes Rohm & llaas sulfonic acid type resin.
February, 1955
of 80.4 per cent, based on the starting compound, C14labeled barium carbonate. REFERENCES (1) Pijoan, M.. Gujovich. H. J., and Hopwood, M Y.,
u.(gj
%&:$:;
107
~~~;ff;.7f";d5"89,"1f~!).
(3) Dauben, W. G . , Reid, J. C . . and Yankewich. P. E., Anal. Chem.. 19, 828(1947). (4) Gilman, H., Zoellner, E. A,, and Kickey, J. B . , J . A m . Chem. SOC.,51, 1576(1929). (5) Hkkinbottom, W. J., "Reactions of Organic Compounds, Longmans, Green and Co., New Ynrk, 1948, p. 242.
The Determination of Iodide-Iodate Activity in Sodium Radio-Iodide (I131)by Automatic Scanning of Paper Chromatograms * By JOHN J. PINAJIAN and JOHN E. CHRISTIAN RJ values of different width filter paper chromatograms using 7 5 per cent methanol
in a n ascending system are presented for iodide and iodate. The chemical identity of the spots is determined by the use of carrier iodide and iodate. T h e iodide spot was developed by spraying the dry chromatogram with starch hydro e n peroxide solution. The iodate spot was developed with a spray of ascorbic aciff-starch solution. Description of the equi ment is given. T h e relationship of the chart drive s eed and the optimal slit wi& to the time constant of the countin rate meter is 8scussed and the minimal slit width calculated for the instrument u s e k Integration of the curves gave areas representing the total activity at each spot. T h e ratio of the iodide-iodate activities thus determined differed from the relative readings of the counting rate meter. mm., and 20 mm. were used). The spots were air dried and a drop of carrier solution (using a standard dropper) was then spotted at the same site. The carrier solution contained 1.66 mg. potassium iodide, 2.14 mg. potassium iodate, and 10 mg. sodium bicarbonate per ml. The paper was air dried and a small strip of tin foil was folded over the bottom as a weight. 'A 250-ml. ground-glass stoppered graduated cylinder was used for the chamber. Methanol, 25 ml. of 75 per cent,2was pipetted into the bottom and the strip was hung so that one-half inch of the tin foil weighted bottom was immersed in the solvent. The ground glass stopper held the paper in place. The chromatogram was allowed t o develop for four hours ddring which time the solvent front traveled approximately 30 cm. The strip was withdrawn from the cylinder, the solvent front marked immediately, and the strip allowed to air dry. Chemical Identification of the Spots.-The spots on the filter paper chromatograms were chemically identified by spraying the paper with a fine spray of Starch Test Solution, U. S. P. XIV, spraying with Hydrogen Peroxide Solution, U. S. P. XIV, and finally spraying with ascorbic acid solution, 5 per cent. The sprays were applied with a DeVilbiss EXPERIMENTAL No. 251 atomizer. The ascorbic acid solution was prepared fresh each month. Paper Chromatography.-A finely drawn capillary The spray of starch and hydrogen peroxide gave a was inserted into the Sodium Radio-Iodide (IlS1)l rapid (less than one minute) response (brown color) and approximately one lambda was allowed t o be with the iodide spot, while the iodate spot remained drawn up by capillary action. This was then unaffected. With the addition of ascorbic acid, the spotted one inch from the bottom of 18-inch strips iodate was reduced promptly (less than one minute) of Whatman No. 1 filter paper (widths of 8 mm., 10 t o give a purple color changing t o brown within two * Received August 28, 1954, from the Bio-Nucleonics minutes. The spraying of starch-iodide impregnated paper Laboratory. School of Pharmacy, Purdue University. West Lafavette. Ind. with ascorbic acid gave negative rcsults, cvcti after
of an investigation concerning t h e assay of Sodium Radio-Iodide (1131) used for medicinal purposes,' it became necessary t o distinguish between the iodide and iodate forms of the activity present. Since the amount of material present for analysis represented something in t h e order of 10-l2 Gm. ordinary techniques of differentiation were not suitable. The technique of paper chromatography appeared t o be the most suitable and the most convenient instrument readily availablefor the resolution of the two forms of 1131 activity. Indeed, once separated, the very nature of the iodide or iodate prese n t allows for a fairly accurate estimation of the relative ainourits present. T h e common practice of utilizing autoradiographic procedures with subseyuen t visual or densitometric determination of the amount of fogging was not suitable because of t h e time factor involved. Various direct methods of scanning have been described (2-7). N THE COURSE
I
hksented to the Scientific Section of A. PB. A.. Boston, meeting, August, 1954. 1 Obtained frnm the Oak Ridge National Laboratory, Oak Ridge, Tenn.
* The solvent system used here was first suggestcd Iiy Gleason (8), Abbott Lahoratories, Oak Ridge, Tenn.
108
JOURNAL OF THE
AMERICAN PHARMACSUTICAL ASSOCIATION
Fig., 1.-Recording of the iodide and iodate activities of a filter paper chromatogram of sodium iodide ~ 1 3 9 . (The lower most marking locates the spotting site and the upper most marking locates the solvent front line.) one hour. The addition of hydrogen peroxide to the iodate spot after treatment with starch spray similarly gave negative results. Radioactivity Assay of the Chromatograms.-For determining the activities of the iodide and iodate spots, the strips were pasted along the cdgc of a section of chart paper (Esterline-Angus Chart 4309-C), allowing alternating 30-cm. sections of clear chart paper in between. The chart paper was then rolled on t o the spindle of a 1-ma. EsterlineAngus recorder. Small weights were clipped on the end of the chart paper. The chart paper was arranged so that the chromatogram passed in front of a thin slit of a brass plate which shielded the Geiger-Muller c o ~ n t e r . ~ Constant geotpetry was maintained by placing a lead block in back of the chart paper. The pulses from the Geiger-Muller 8 End-window Geiger-Mliller counter wit11 a 2.3-mg./cin.' mica window.
Vol. XLIV, No. 2
tube were fed to a counting rate meter' and from there to the recorder. As the paper chromatogram spotting line passed a line a t the middle of the slit, the pen was manually moved across the chart t o give a spotting line on the chart. Similarly, as the solvent front line moved across the marker, another line was made on the chart. With the arrangement described, specification as to the chart drive speed and the optimal slit width is dependent upon the time constant of the counting rate meter. The value for the time constant varies in different circuits and sensitivities from one second to about one minute and is minimal for the highest counting rate sensitivity in a given circuit. Thus, it is advantageous t o work whenever possible with a high level of activity in order t o minimize the time constant of the rate meter response.6 When this is done, the practical limiting factors are the chart drive speed and the slit width. With a chart drive speed of 28 cm./hr., the minimal slit width was calculated t o be 3.4 mm. The slit width was machined t o 5.0 mm. and was made 20 mm. across to accommodate various widths of filter paper strips. The R , values obtained under the conditions described were 0.76 f 5% and 0.45 f 5% for iodide and iodate, respectively, and were in correspondence with R, values determined by the conventional method. The method described has the advantage of presenting well-defined peaks which represent the centers of density. Thus the uncertainty of the R, value is considerably reduced by simple measurement of well-defined distances. A sample recording is reproduced in Fig. 1. A planimeter was used t o measure the area beneath the curves. This area represents the total number of counts in the spot. The background was subtracted by extending the horizontal base line. The distribution of the radioactivity between the iodide and iodate spots in the sample recording illustrated above was found t o be 93.6 and 6.4% for iodide and iodate, respectively. The distribution as calculated from the relative readings of the counting rate meter was found t o be 92.4 and 7.6% for iodide and iodate, respectively.
SUMMARY
A simple automatic scanning and recording device has been described for the paper chromatography. T h e relationship of the chart drive speed and the optimal slit width t o the time constant of the counting rate meter has been discussed and the minimal slit width has been calculated for the instrument used. R,values of radioiodide filter paper chromatograms have been presented. A method for determining the ratio of t h e iodide-iodate activities present have been described. A method for the chemical identifica4 Model 1615, Radiation Sentinel, Nuclear Instrument and Chemical Corp., Chicago. Ill. 6 One should nut, of course, count at such a rate that resolving time corrections become necessary. For example, with the full-scale response of the counting rate meter set a t 5000 c. p. m. and the resolving time of the Geiger-Miiller counter 200 p sec., the correction for losses at the maximnm rate will be aoDroximatelv 1.68 Per cent. Since the countinn rate varies from zero thkough 'the maximum t o zero for given spot, the resolving time error in the estimation of the activity of the spot will be less than 1.68 per cent.
a
SCIENTIFIC EDITION
February, 1955
tion of the iodide and iodate spots on t h e paper chromatograms has been developed.
REFERENCES (1) Miller L. C . Drug Sfandards 22 168 1954). (2) Mulle;, R. H., and Wise, E. N . , ’ A n J . Chcm.. 23, 207 (1951).
109
(3) Jones. A. R., ibid., 24, 1055(1952). (4) Williams, R. R . , and Smith, R. E,, Proc. SOC.Expfl. Biol. M c d . , 77, 169(1951). (5) Rockland L. B. Lieberman, J., and Dunn, M . S., Anal. Chcm. 24 ’778(1962). (6 Wintkin ham, F. P. W., Harrison, A., and Bridges, R. Analyst,%7. lQ(1952). (7)’Frierson, W. J., and Jones,J. W.. Anal. Chem., 23,1447 (1951). (8) Gleason, G. I., Personal communication.
d.
Properties and Applications of Powdered Polysaccharide Acids* I.
Preparation and Titration Curves
By JOSEPH V. SWINTOSKY,t LLOYD KENNON,$ and JAMES TINGSTAD Several new powdered polysaccharide acids, namely elm acid, quince acid, and plantag0 acid, were prepared by ion exchange, followed by spray drying. These acids, carboxymethylcellulose acid and several analogous type acids were titrated potentiometrically, and the shape of the titration curves were indicated to be quite typical of the synthetic cation exchangers. Approximate acid equivalents and pKa values-were determined for some of these substances. A number of pharmaceutical applications for these acids are suggested.
RIDOUThave described the use of powdered alginic acid as a tablet disintegrant (1) and we have similarly noted a n d reported this property (2) for the spray-dried powdered acid form of carboxyrnethylcellulose (HCMC). Some recent publications have also described the cation exchange properties of alginic acid (3, 4, 5) a n d chemically modified cotton fabrics (6). T h u s a number of the naturally occurring gums and related products possess the chemical structural requirements for ion exchange. Possible uses already discovered for some of the polysaccharide acids, coupled with other chemical a n d physical features, suggested a program embracing their preparation a n d an investigation of their pharmaceutical applications. ERRY AND
EXPERIMENTAL Materials.-The polysaccharide acids employed in this study were derived from algin, sodium carboxymethylcellulose, linseed, elm, quince, acacia, and plantago seed. Alginic acid employed in this study was Ke1acida.l The powdered linseed acid and the arabic acid were prepared by ion exchange and spray drying in these laboratories, and have been previously described (2, 7). Powdered HCMC has also been prepared (2); but for this study, a slight modification of the previous method of preparation was followed. Preparation of Elm Acid Solution.-Approximately 2.3 Kg. of elm bark* was used. Ten I,. of Received April 22, 1954, from the School of Pharmacy, University of Wisconsin, Mahson. Supported in part by the Research Committee of the Graduate School from funds supplied by the Wisconsin Alumni Research Foundation 7 Present Address: Smith, Kline & French LaboratorieP, Philadelphia 1 Pa. $ Fellow, Akerican Foundation fer Pharmaceutical Education 1 Kelco Co..Chicago, Ill. 2 Elm bark, quince seed, and plantago seed were obtained from S . B. Penick Co.,N. Y.
boiling distilled water was poured over the bark contained in a porcelain pan. The water was allowed t o cool t o room temperature, and the mucilaginous layers formed on the bark surfaces were dispersed into the water by rubbing. The rubbing process was repeated after two hours of maceration. The liquid infusion was then separated from the bark. The bark was again subjected t o the steeping process. About 20 L. of an orange-brown mucilaginous infusion of elm bark was obtained. The infusion was saturated with chlorobutanol to inhibit fermentation and was then strained through two layers of muslin. The mucilaginous polysaccharide was precipitated from solution by pouring 60 L. of alcohol, into the 20 L. of infusion. It appeared as a white fluffy substance somewhat like paper pulp and was collected by filtration through muslin. It was then expressed free of liquid by squeezing in the hands; the material became light ash colored. In 150 cc. of alcohol it assumed a very friable character and crumbled into small particles upon stirring. Distilled water was added in small increments with stirring t o permit uniform wetting and hydration of the product. When a total volume of 1 L. was attained, the product, a thick homogeneous mucilage, was poured with stirring into 1 L. of boiling distilled water. After further swelling, it was diluted with warm distilled water to a total volume of 8 L.and after standing several hours, 24 L. of alcohol were added to reprecipitate the polysaccharide. The precipitate was filtered through muslin and redissolved in water to a volume of 20 L. The series of alcohol precipitations were performed to separate the polysaccharide gum from the other principal extractive materials of the bark. T o obtain the elm acid solution, the viscous gum solution, maintained a t about 50-60°, was passed through a series of eight 4-L. flasks, each flask containing about 500 Gin. of acid charged 1R-120 cation exchange resin.3 About fifteen to twenty minutes Rohm & llaas sulfonic acid type resin.