Aug.,
1917
T H E JOKR,VAL O F I N D C S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
A METHOD OF ASHING ORGANIC MATERIALS FOR THE DETERMINATION OF POTASSIUM By P. I,. BLUMENTHAL, A. M. PETER,D. J. HEALYAND
E. J.
GOTT
Received May 7, 1917 INTRODUCTORY
I n a series of researches now in progress i t was necessary t o determine, quite accurately, small quantities of potassium in t h e presence of much greater amounts of organic materials, chiefly proteins, f a t t y acids and carbohydrates. Under such conditions, mechanical losses during ashing a n d t h e possibility of volatilizing potassium compounds would introduce serious errors into t h e work. T h e object of this investigation, therefore, was t o ascertain t h e best method of ashing organic substances in which potassium was t o be determined. This article is t h e first of a series of investigations. Other papers will follow as rapidly as t h e results warrant. Of t h e various salts of potassium t h e chloride and t h e carbonate are t h e most volatile. The potassium of organic compounds, when ashed, is usually converted t o t h e carbonate, except where sufficient chloride or sulfate ions t o combine with all of t h e alkali are present. T h e nitrate, oxalate a n d other potassium salts of organic acids are converted t o t h e oxide, hydroxide or carbonate, depending upon t h e conditions of ignition a n d t h e quantity of carbon dioxide present. Rose’ states t h a t if t h e alkalies are present only as chloride it is possible, through lack of care, t o volatilize t h e small amount of alkali salts present. On page 554 of t h e same book he states t h a t t h e chlorides of t h e alkalies are much more easily volatilized when heated in t h e presence of air t h a n when air is excluded. Norton a n d R o t h 2 show t h a t potassium sulfate is nearly twice as stable as t h e carbonate a n d about seven times more stable t h a n t h e chloride. I n addition t o t h e possibility of loss of potassium salts by volatilization, there is every reason t o believe t h a t , i n t h e removal of considerable quantities of organic material or ammonium salts b y burning, some potassium is lost mechanically. R E A G E N T S A N D MATERIAL
The organic material selected for experimental work was a bacteriological culture medium containing small amounts of potassium salts. It varied slightly in composition from time t o time, b u t t h e ratio of organic matter t o potassium salts was fairly constant. This medium contained about 0.7 g. of organic matter (proteins, carbohydrates, etc.) in z j cc. of solution. A portion of a high-grade, commercial preparation of potassium chloride was dissolved in water and, after filtering, was partially precipitated by running t h e solution into pure dilute ethyl alcohol, with constant stirring during t h e mixing. T h e finely crystalline salt so obtained was filtered, washed with dilute alcohol, dried for several hours a t 100O , bottled while warm, and to stand in a desiccator Over chloride. A portion Of t h e salt was carefully weighed Out and made up to t h e required volume at 2 o 0 C . This 1
“Handbuch der Analytischen Chemie,” German Edition, 1 (1851),
2
J . A m . Chem. SOC.,19 (1897), 155-6.
835.
-i 3- 3
solution was standardized by carefully evaporating measured portions with platinic chloride solution and, after t h e usual washings with acid alcohol, ammonium chloride solution a n d 80 per cent alcohol, t h e weight of potassium chloroplatinate was obtained and t h e potassium chloride content calculated. Molar solutions of nitric acid, magnesium nitrate and ammonium nitrate were used in certain of t h e exS b y ‘mixperiments; dilute sulfuric acid W ~ prepared ing 184 cc. of distilled water with I O O cc. of concentrated sulfuric acid. T h e acid alcohol used in washing t h e potassium chloroplatinate was made by adding I O O cc. of concentrated hydrochloric acid t o I liter of 95 per cent ethyl alcohol; t h e ammonium chloride solution was of 2 0 per cent strength and was saturated with potassium chloroplatinate in t h e usual manner. METHOD OF ANALYSIS
Twenty-five cc. of medium were pipetted into a suitable silica evaporating dish, potassium chloride solution r u n in from a burette (except in t h e blanks) a n d t h e sulfuric acid and oxidizing agents added b y means of dropping pipettes. The solution was evaporated on a rapidly boiling water bath, as low as possible. The black, gummy residue was carefully heated over a free flame or in a muffle furnace until white.’ On cooling, z t o 4 cc. of I : I hydrochloric acid were added, a n d t h e ash allowed t o digest at room temperature over night, keeping t h e dishes under a bell jar. The solution was then filtered into small beakers, washing with hot water, a n d policing t h e dishes t o remove t h e last traces of residue. Some calcium sulfate a n d silica are removed by t h e filtration. After t h e addition of t h e requisite excess of platinic chloride, t h e filtrate was evaporated t o dryness on t h e water b a t h and, after cooling, was taken u p with a few cc. of t h e acid alcohol. After settling, t h e clear yellow liquid was decanted through a glass filtering tube, having a n asbestos mat, t h e residue was again washed b y decantation with acid alcohol a n d then with t h e 80 per cent alcohol, t o remove t h e last traces of platinum chloride a n d hydrochloric acid from t h e preceding wash. T h e bulk of t h e precipitate in t h e beaker was then treated with 4 t o 6 cc. of t h e ammonium chloride wash, using a rubber policeman t o break u p t h e lumps a n d larger crystals, and stirring t o hasten t h e solution of calcium a n d magnesium sulfates. After settling, t h e wash was decanted through t h e same t u b e which contained a little of t h e precipitate and t h e main precipitate was washed repeatedly b y decantation with t h e ammonium chloride solution until clean.2 T h e main portion of t h e chloroplatinate was then transferred t o t h e filtering tube, t h e beaker policed, washed 1 I t was noted that where carbonaceous material remained, even of graphitic nature, the results were erroneous. If the carbon cannot be removed at one heating, ,the extracted residue should be ashed again and the soluble material of the ash added to the main portion. As this is a rather tedious procedure, and one liable to introduce further errors, the method herein explained was developed with a view to removing all the organic matter at one heating, even at the risk of losing a trace of potassium by volatilization. 2 This material was examined by a hand lens until the operator was so familiar with the appearance of a clean precipitate as to render use of a glass unnecessary.
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
7 54
thoroughly with 80 per cent alcohol, and t h e t u b e dried for a n hour a t 98’ C. After cooling and weighing, t h e precipitate was dissolved out by washing with hot water. The t u b e was t h e n filled with 80 per cent alcohol a n d after drawing this through by suction i t was again dried for a n hour and, after cooling, reweighed. The difference in weight represented K2PtC16. Some silica usually remained on t h e asbestos m a t b u t in no case was i t found t o vitiate the results. T h e direct method of estimating potassium without removing Fe, C a or Mg, as herein described, has proved very satisfactory in this laboratory over a period of eight years. EXP E RI M E liT A L
T o determine whether sulfuric acid would retard possible loss of potassium, and whether heating in a muffle furnace offered any superiority over t h e usual method of burning off b y moving t h e silica dish slowly over a Bunsen flame until t h e main evolution of gas had ceased, a n d then igniting till t h e residue was white, a series of t e n experiments (Table I , Series A) was carried out, using z j cc. of t h e medium for analysis. Xot knowing t h e exact potassium content of t h e medium, i t was necessary t o carry out some check analyses in which known amounts of potassium were added t o t h e medium, in order t o arrive a t t h e amounts recoverable. A second series of experiments (Table I, Series B) was, therefore, made in which j cc. of KC1 TABLEI-RESULTS
25 Cc. OF MEDIUM B Y ASHING I N A MUFFLE FURNACE AND OVER A BUIVSEN FLAME SERIESA: N o ADDITION SERIESB : KC1 ADDED SULFURIC Milligrams K Milligrams K No. HEATING ACID Found Av. Taken Found Error 1 Bunsen None 7.56 6.51 -1.05 None ::;214.25 7.56 6.24 -1.32 2 Bunsen None 4.14 \ 7.56 6.19 -1.37 3 Bunsen 4 Bunsen ........ .... 5 Bunsen 4’29 ........ .... 6 Muffle 5 drops 4 . 7 1 ) 7.79 7.74 -0.05 7 Muffle 5 drops 4 . 5 5 4 . 6 3 2.79 7.82 +0.03 8 Muffle 5 drops 4 . 6 3 i.79 7.79 0.00 9 Muffle 5 drops 7.62 7.31 -0.31 10 Muffle 5 drops 7.62 7.21 -0.41 ON
::::} f
::ti]4’31
solution were added t o each sample; t h e other details were identical with Series A , except t h a t Nos. 4 a n d 5 were omitted. The potash content of t h e medium was taken from t h e averages in Series A, each average being assumed as a blank for t h e group in question. From t h e results of these Series 4 a n d B, it is quite evident t h a t in t h e absence of sulfuric acid, potassium is lost, presumably by volatilization, while there is a shade of evidence in favor of using a muffle furnace, because t h e results are a trifle higher. Theoretically, t h e muffle should reduce mechanical losses due t o spattering and local superheating, because of uniform heating. I t seemed possible, from Series B, t h a t a larger quantity of sulfuric acid might improve t h e results even more. T h e sulfuric acid acts as a n oxidizing agent in removing carbon and also as a “fixing” agent for t h e alkali salts present; therefore, a larger q u a n t i t y of t h e acid ought t o hasten t h e ashing process a n d reduce t h e possibility of loss of alkali salts b y volatilization. Table I1 shows t h e effect of increasing t h e quantity of acid; t h e potassium content of this medium was slightly increased due t o decrease in volume during sterilization.
Vol. 9, No. 8
c:
TABLE11-SERIES ‘LTSING 25 CC. OF Dilute 10 HzS04 drops Milligrams / 5 . 1 5 K found (5.21
1
AVERAGE
5.18
RESULTSWITH INCREASING QUANTITIES OF ACID, MEDIUMAND ASHINGIN THE MUFFLEFURNACE 15 20 0.5 1 2 3 4 drops drops cc. cc. cc. cc. cc. 5.02 5.40 5.16 5.18 5.11 5.19 5.37 5.00 5.68 5.18 5.13 5.16 5.32 5.24 5.16 5.13 5.26 5.01 5.41 5.16 5.19 5.14 5.26 5.30
The variations in Table I1 are quite small a n d one is hardly warranted in drawing conclusions from t h e analyses. However, t h e samples containing larger amounts of acid ashed more readily a n d left little carbonaceous residue with t h e silica, etc. T h e next series of experiments contained larger quantities of acid t o throw further light upon t h e point. I n Table I11 are given t h e results of another parallel series, carried out t o determine whether t h e muffle or freeflame method of ashing gave t h e more accurate results. cc.
cc.
HzSOc KC1 3 .. 3
5
3
in
3
25
TABLE111-SERIES D MUFFLEFURNACE FREE FLAME Milligrams K Milligrams K Taken Found Error Taken Found Error ... 4.84 4.52 .. 4.91 .... . . . 4.55 .. . . . 4.84 .... 8.17 z . 9 8 -0.19 7.86 6.80 -1.06 / . 5 5 -0.62 7.84 6 . 8 9 -0.95 8.17 8.19 8.17 -0.02 1 1 . 4 9 11.43 - 0 . 0 6 1 1 . 1 6 1 1 . 1 1 -0.05 1 1 . 4 8 11.32 - 0 . 1 6 11.18 9 . 5 8 -1.60 1 1 . 5 0 1 0 . 7 9 -0.71 21.42 20.69 -0.73 2 1 . 1 2 19.21 -1.91 21.44 19.70 -1.74 2 1 . 1 0 1 8 . 7 9 -2.31 21.42 21.16 -0.26
...
.... ....
...
The first five results in Table I11 are blanks on potassium content of t h e medium. These results are not acceptable in point of agreement, though some of t h e individual analyses are sufficiently close t o theory; t h e analyses made by means of t h e muffle furnace are higher t h a n those where t h e samples were ashed over a free flame. This means t h a t there was less mechanical loss (spattering, foaming, etc.) a n d in all subsequent analyses t h e samples were burned in t h e muffle furnace. It was quite difficult t o burn t h e last bit of carbon in this set because i t was more or less graphitic in nature and was quite refractory. T o avoid possible errors due t o adsorption of potash in washing by t h e carbon remaining unburnt, etc., i t was sought t o find a method of ashing which would readily remove all of t h e carbon from t h e ash. A series of experiments was tried in which t h e samples were evaporated a n d then charred over t h e free flame, after which t h e requisite amount of sulfuric acid a n d I O t o I 5 cc. of water were added a n d t h e whole evaporated a second time a n d ashed. This treatment was devised in order t o relieve t h e sulfuric acid of p a r t of its function as a n oxidizer: t h e charred mass was readily softened b y water and acid and t h e subsequent ignition was a little easier t o conduct because there was less foaming, etc. T h e analyses are quoted in Table IV, Series E. Further investigations were made along t h e same line in which part of t h e carbonaceous material was removed b y initial heating a t relatively low temperatures, various materials being added t o assist in t h e oxidation. Table I V , Series F, shows t h e results obtained when t h e samples were first evaporated with 5 cc. of molar solutions of nitric acid, ammonium nitrate or magnesium nitrate, charred over a free flame a n d then treated with sulfuric acid diluted with water, evaporated
I*
Aug., 1917
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
---
TABLE IV-EFFECT OF ADDITIONOF OXIDIZER -SERIES E-h-o OXIDIZER-SERIESF-OXIDIZER ADDEDK C l &So4 --Milligrams KKC1 &SO4 Oxidizer --Milligrams KCc. Cc. T a k e n F o u n d Error Cc. Cc. 5 Cc. Taken F o u n d E r v o r .. . .. 6.27 . . . . 5 "03 6.67 , . .. . . 6.00 , . . .. .. 5 "03 6.67 .. 6.14 5 "01 10 l 2 : 9 8 12.94 - 0 : O i 10 l 2 : ? 6 12.99 $0123 5 "03 12.96 12.83 -0.13 10 12.75 12.73 -0.02 10 12.99 12.55 -0.44 5 "0s 10 12.77 12.62 -0.15 10 12.77 11.82 -0.95 10 . . , 6.45 . . . . 12.76 12.12 -0.64 10 6.45 12:?6 11.83 -0:93 . 6.33 . . . 10 10 5.76 10 10 12.74 12.86 f 0 . 1 2 ... 6 . 3 0 . 10 10 12.77 11.89 -0.88 10 5 5.82 10 5 l i : 6 8 1 3 . 0 8 S0:40 . . 5 Mg(N03)Z . . . 6.70 .... 10 5 12.67 13.03 + 0 . 3 6 . . 5 Mg(N03)~ 6.72 10 5 12.69 12.91 $0.22 10 5 M g ( N 0 3 ) ~13:02 12.99 -0:Oi 10 5 12.69 13.13 $ 0 . 4 4 10 5 Mg(N0a)n 1 3 . 0 0 12.60 -0.40 10 5 1 2 . 6 8 11.89 -0.79 10 5 Mg(N03)z 13.03 12.76 -0.27
755
moving carbon, with a minimum loss of potassium. I n Table V, Series G , Experiments I t o 7 were carried . .. .. . out as follows: The sample (with or without KC1) was treated with 5 cc. of molar nitric acid and 6 CC. of sulfuric acid, evaporated t o pasty condition and t h e n .... ashed in t h e muffle. Nos. 8 t o I I were treated with t h e same amounts of H N 0 3 and evaporated as low as possi... .. .. . . . ... ble on the water bath, diluted with water and t h e n carried down with 6 t o 7 . j cc. of sulfuric acid. Nos. 1 2 t o 18 were similar experiments on a new medium, S o s . 19 t o 2 3 were evaporated with nitric acid and a n d ashed. The quantities of sulfuric acid were varied charred in a free flame, as were t h e determinations in so as t o determine under what conditions t h e removal Series F, after which sulfuric acid and water were added and t h e mixture evaporated t o low volume and of carbon could be most readily accomplished. As in t h e other tables, t h e first results under t h e ashed. Nos. I t o 7 yielded results which are slightly closer column headed "hIg. K found'' represent t h e amount t o theory t h a n any of the other methods and they are of potassium found in t h e organic medium: t h e v a r i a tions from table t o table are due t o differences in t h e more regular t h a n those of t h e other methods. Since concentration of t h e medium, which varied in t h e differ- this procedure was shorter, it was decided to investie n t preparations. The differences in t h e values ob- gate t h e method further. These experiments, t h e results of which appear in tained for t h e same amount of medium in t h e same table are due t o the impurities present in t h e reagents Table V I I , Series H, show greater regularity and closer used in each method tried a n d t o mechanical losses duplication of individual series t h a n any method as yet tested. I t will be noted t h a t practically all t h e or errors inherent t o t h e method. I n t h e above experiments, on attempting t o char results are low, t h e maximum error being 0.46 mg. those determinations which had only nitric acid present, where 2 1 . 8 1 mg. were taken, or about 2 per cent of t h e material swelled rapidly to a very voluminous t h e total potassium present. I n working with such mass, resembling t h e ash obtained from burning mer- small quantities as have been employed in this investicuric isothiocyanate. T h e ammonium and magnesium gation, such a n error, while not desirable, is relatively nitrate experiments deflagrated: t h e latter was a slower negligible, as t h e long process involved in t h e analysis a n d less violent deflagration a n d t h e ash was more is bound t o cause some mechanical losses. Series G porous, b u t t h e presence of t h e magnesium salts ren- shows t h a t , while considerable quantities of sulfuric dered t h e removal of t h e last traces of carbon difficult acid are necessary, a large excess is t o be avoided, bea n d t h e subsequent treatment of t h e ash for estimation cause of t h e increased danger of spattering during t h e of potassium was rendered very tedious for t h e same removal of carbon by burning. I n closing i t should be stated that t h e amounts of reason. T h e mechanical losses due t o deflagration eliminate t h e last two methods of treatment, b u t t h e nitric and sulfuric acid used in this work will not necesnitric acid method gave promise of better results, sarily be found suitable for all potassium determinaparticularly if t h e formation of t h e puffy char could be tions where organic matter is present. With 0 . 7 g. of controlled. various organic materials. and amounts of potash varyAccordingly, a series of determinations was outlined ing from 4 mg. t o 2 1 mg., it has been found advisable t o s t u d y t h e action of nitric a n d sulfuric acids in re- t o use a t least 5 cc. of molar nitric acid and t h e same TABLEV-EFFECT OF NITRICACID ( 5 C c . USED I N EACHEXPERIMENT) amount of I : I sulfuric; t h e amount of nitric acid SERIES G SERIESH can be varied, depending upon t h e quantity and KC1 %SO4 --Milligrams K-KC1 HzSOa-Milligrams Knature of t h e organic matter present, as most of t h e No. Cc. Cc. Taken Found Error h'o. Cc. Cc. Taken Found Evror ... 1 . . 6 . . . 6.80 .... 1 ,. i.5 5.68 .... excess acid will be removed through replacement b y . . . 6.73 ... 2 . . i.5 2 ,. 6 5.82 3 10 2 . 5 12106 1 1 . 7 5 -0:ji sulfuric acid and volatilization during evaporation. 9 . 9 3 9 . 9 1 -0.02 3 5 6 4 10 1 . 5 12.04 11.96 -0.08 4 5 6 9 . 9 1 9.97 +0.06 5 10 7 . 5 12.07 1 2 . 0 1 -0.06 The amount of sulfuric acid should not be increased, 6 15 7 . 5 15.22 l 5 , I O -0.12 5 10 6 13.08 13.24 +0.16 i 15 7 . 5 15.20 1 5 . 0 6 -0.14 except where much larger quantities of organic matter 6 10 6 13.06 13.07 + 0 . 0 1 8 15 i.5 15.22 1 5 . 8 4 -0.38 7 10 6 13.09 1 2 , 7 6 -0.31 ( 2 to 3 g.) are used, because of t h e possibility of greater 9 25 z . 2 21.50 21.32 -0.18 10 25 1 . 3 21.52 21.26 -0.26 8 .. 6 . . . 6.49 ... losses through spattering. 1 1 25 i.5 2 1 . 5 0 21.30 -0.20 12.80 13.15 + 0 . 3 5 9 10 6 12 . . 5 . . . 5.85 , . . . 12.78 13.02 + 0 . 2 4 10 10 6 13 . . 5 ... 5.93 .... CONCLCSIOIiS 12.81 13.23 JrO.42 11 10 6 14 . . 5 . . . 6.04 . . . . 15 . . 5 , . . 5.95 12 , , 7 . 5 ... 5,87 . ... I-In ashing organic material, potassium is usualIy 16 5 5 9 . 1 0 9 . 1 9 +0:09 13 , . 7 . 5 ... 5.59 .... 17 5 5 9.08 9.14 +0.06 lost by spattering and volatilization in removing 14 10 7 . 5 1 2 . 0 4 11.75 -0.29 18 5 5 9.10 9 . 1 4 1.0.04 15 10 7 . 5 1 2 . 0 5 1 1 . 8 1 -0.24 19 10 5 12.25 12.04 -0.21 organic matter and ammonium salts. 12.23 12.04 -0.19 20 10 5 16 15 7 . 5 15.20 1 4 . 3 5 -0.85 21 10 5 12.26 12.18 -0.08 11-Burning off carbon in a muffle furnace leads t o 17 15 7 . 5 1 5 . 1 8 1 3 . 4 6 -1.72 22 15 5 15.39 15.39 0.00 18 15 7 , 5 1 5 . 2 0 15.15 -0.05 15.41 15.23 -C.18 more uniform results t h a n direct heating over a free 23 15 5 24 20 5 18.54 18.32 -0.22 19 . . 6 . , . 7.07 . . . . flame. 25 20 5 18.56 18.35 -0.21 20 .. 6 . . . 6.86 , , , . 26 20 5 18.54 18.37 -0.17 21 10 6 13.28 13.24 -0.04 27 25 5 21.79 21.37 -0.42 111-Converting t h e potassium salt to sulfate re13.26 12.41 -0.85 22 10 6 28 25 5 21.81 21.35 -0.46 duces volatilization losses. 23 10 6 13.29 13.35 + 0 . 0 6 29 25 5 21.79 2 1 . 3 8 -0.41
756
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
IV-Moistening t h e sample with sulfuric acid is not sufficient: enough sulfuric acid should be added t o act as a n oxidizer for carbon a n d t o convert all inorganic elements present t o sulfate. V-Direct evaporation of the sample with nitric a n d sulfuric acids, preliminary t o burning off organic matter, has proved the best method of securing uniform results and has materially reduced volatilization losses. AGRICULTURAL EXPERIMENT STATION LEXINGTOK,KENTUCKY
SOURCES AND COMPOSITION OF SOME COMMERCIAL INVERT SUGAR SYRUPS WITH NOTES ON SORGHUM SYRUP B y STROUD JORDANA N D A. I,. CHESLEY
houses. It is so blended t h a t i t rarely carries over 7 2 . 5 per cent total sugars a n d a varying amount of this is invert, which may be seen from t h e analyses given later. It is impossible t o determine the acid value of this material with a n y degree of accuracy since t h e color is too dark t o allow titration. NETHODS O F ANALYSIS
For all determinations, t h e official methods, as given in Bull. I07 (revised), U . S. Dept. of Agr., Bur. of Chem., have been used. These methods have been replaced b y later modifications appearing in t h e Journal of Association of Oficial Agricultural Chemists, where t h e y may be found. I n this connection it is well t o point out t h e fact t h a t sucrose cannot be estimated in these solutions b y t h e Clerget method,’ a n d t h a t copper reduction methods have always been employed.
Received F e b r u a r y 8. 1917
At t h e present time numerous samples of commercial invert sugar syrups may be bought on t h e market under different trade names, a n d during t h e past year it has been estimated t h a t more t h a n z,ooo,ooo gallons of this material were used in t h e several industries which represented an expenditure in excess of $I,OOO,OOO. T h e use of this material is on t h e increase a n d there is no limit t o its application, for the great value of such a solution is t h a t t h e sugars will not harden, as will sucrose, a n d t h a t it will retain approximately 14 per cent moisture under most conditions. This fact has been utilized t o prevent hardening of materials b y substituting all or a portion of the sucrose used with invert syrup. A wide variation in these syrups will be found, going from inverted cane sugar syrups through inverted raw cane sugar syrups into the more or less complex molasses a n d invert sugar mixtures, which sometimes contain materials other t h a n sucrose and invert sugar. It is unnecessary t o go into detail as t o history, character a n d properties of invert sugar, for this is thoroughly covered in t h e literature,’ b u t in general two grades may be bought on t h e market: these are known as “light” a n d “dark” or b y some special brand. T H E LIGHT SYRUP is generally composed of a large amount of invert sugar a n d a small amount of unchanged sucrose, along with a trace of ash a n d from 0.05 t o 0.2 per cent acidity, when calculated as tartaric. Organic acids are generally used in t h e preparation such as citric, tartaric, formic, a n d acid salts, as cream of t a r t a r , but in some instances hydrochloric acid has been detected up t o 0.15 per cent, partly combined a n d partly free. T H E D A R K SYRUP is a complex mixture, being composed of invert raw sugar syrup, a mixture of invert r a w sugar syrup a n d molasses, light invert sugar s y r u p a n d molasses, or invert sugar syrup a n d soured honeys along with wastes occurring around sugar 1 Allen’s “Commercial Organic Analysis,” 4 t h Ed., pp. 375-6; British P a t e n t , 16,540, 1889, Alfred Wohl; Browne’s “Handbook of Sugar Analysis,” p. 659; Ibid., p. 273; Chemical Abstracts, 1 (1907). 645; Deul. Zuckwind, 31, 1988; U. S. Dept. Agr., Bur. of Chem., Bull. I S , 75-6; Ibid., 110, 63-4; U. S. Dept. Agr.. Farmers’ Bull. 477, 30; U. S. P a t e n t , 1,181,086, 1916, N. W. Taussig.
Vol. 9, No. 8
RESULTS
Analyses of products gathered from various sources during t h e past four years are given below in percentages a n d under each grouping will be found samples of similar origin. No.
A
. B
C
M
1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10
LIGHT SYRUP Invert Sucrose Ash 77.80 3.33 0.02 78.60 2.87 0 . 1 2 76.73 0 . 9 8 0.06 76.70 2.19 0 . 0 5 77.55 2.26 0 . 0 1 6 9 . 2 0 1 1 . 8 8 Traces 73.90 8 . 6 1 Traces 72.62 6.37 Traces 68.08 10.90 0 . 1 1 76.80 2.56 0 . 1 1 74,72 2.27 74.96 2.58 75.82 2.11 75.76 2.30 Traces 73.69 3.14 Traces 75.29 0.49 Traces 74.46 3.47 Traces 2.49 Traces 74.96 2.73 Traces 74.33 1 . 9 4 Traces 74.96 44.05 33.57 Traces 5 . 4 2 Traces 72.37 65.92 14.29 Traces 69.20 11.88 Traces 2.44 0.06 75.85 8.27 0 . 4 0 71.40 47.96 30.58 Traces 66.00 11.50 Traces 9 ~. 47 _ . Traces 67.88 6 . 5 1 Traces 71.42
DARK SYRUP
No. ’ I n v e r t Sucrose Ash A’ 1 36.92 3 5 . 0 9 0 . 3 9
B‘
C’
M’
2 3 4 5 1 2 3 4 5
48.52 47.62 47.04 51.32 29.23 36.58 31.57 37.62 53.28 73.65 67.77 71.04 71.82 69.42 46.88 51.58 48.85 47.32 10 35.19 1 68.67 2 64.28 3 55.62 18.00 47.12 54.46 54.08 60.38 61.42 10 43.54
22.62 15.49 22.80 20.35 46.63 36.94 43.46 30.60 23.77 5.30 8.44 4.28 4.01 7.32 22.30 22.29 22.26 21.86 35.84 7.40 6.35 21.13 52.51 26.60 23.24 22.71 14.95 13.82 28.79
1.47 2.44 1.98 1.84 0.22 0.96 1.03 0.87 0.41 0.16 0.06 0.05 0.07 0.12 3.07 2.32 3.51 2.51 2.98 0.98 0.43 0.24 0.99 1.08 0.23 0.04
0.05 0.06 2.41
. Samples marked “ A ” show a very good inversion. T h e ash value of these samples would indicate t h a t mineral matter of some nature had been introduced either t o neutralize acidity or for some special purpose. Samples marked “B” do not show a good inversion. T h e first three show t h a t no mineral matter or foreign material is present because only traces of ash were found, but t h e last two evidently have material other t h a n sucrose added. These inversions are not as nearly complete as t h e foregoing samples, b u t t h e y were probably stopped a t this point in order t h a t there would be less tendency for dextrose a n d levulose t o separate. Samples marked “C” show very good inversion a n d correspond favorably with samples listed under “ A :” however, t h e amount of total sugar is not as great, 1 Jour. A . 0. A. C . , 11, 3 (1916), 138.; Allen’s “Commercial Organic Analysis,” 1, 375.
