An Aly Tical Chemistry

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698 ABSTRACTS OF CHEMICAL PAPERS. Published on 01 January 1909. Downloaded 24/10/2014 13:06:11.

An aly tical Chemistry .

Analysis of Coal-Gas and Similar Gaseous Mixtures ; Estimation of Nitrogen in Coal-Gas. GEORGVON KNORRE(Chem. Zeit., 1909, 33, 717--719).-The first part of the paper consists in a criticism of the methods usually employed in analysing coal-gas, Jager's process (partial cornbustion with copper oxide) may be improved by first expelling the air from the small combustion tube by means of nitrogen, which may be readily made for the purpose by introducing air into the phosphorus pipette. The combustion tube is best made of fused silica. If nitrogen only is to be estimated, 100 C.C. of the coal-gas are at once passed slowly over the red-hot copper oxide. L. DE K. View Article Online

ANALYTICAL CHEMISTRY. 699 Reduction of Perchlorates by Titanium Sesquisulphate. ARTHURSTAHLER (Chem. Zeit., 1909, 33, 759).--h criticism of Rothmund’s process (this vol., ii, 434). The author has used titanium sesquisulphate for the reduction of perchlorates previously (Ber., 1903, 36, 166, 1549), but the results (titration of the excess of the sesquisulphate with iron solution) were not very satisfactory. Good results, however, may be obtained by estimating the chloride formed in the reaction as proposed by Rothmund. For small quantities of chlorine, Richard’s nephelometer (Abstr., 1904, ii, 287) is recommended. L, DE K. Estimation of Iodine in Protein Combinations. LOUISW. RIGGS(J. Arner. Chem. Soc., 1909, 31, 710-717).-1n the estimation of the iodine in protein combinations by Baumann’s method (Abstr., 1896, ii, 487), a portion of the halogen is oxidised to iodate during the fusion. After the estimation of the iodine,.present as iodide, by the usual method, it is necessary, particularly in the case of proteins of small iodine content, to reduce the iodate by Devarda’s alloy and sodium hydroxide, and to estimate the iodine in the iodide thus formed. Mixtures of protein substances and. potassium iodide, analysed by the foregoing process, do not give results comparable with those obtained by the analysis of a protein substance containing combined iodine. Excess of nitrous acid reduces iodates in sdch a way that the iodine cannot be estimated colorirnetrically in carbon tetrachloride. C. S. Estimation of Sulphur in Coals and Cokes. M. HOLLIGER (Zeitsch. angew. Chem., 1909, 22, 1361--1362).-A reply to Dennstedt (compare this vol., ii, 343,435). The author thinks Dennstedt’s process a good one, but advises the use of a small Peligot tube filled with hypobromite solution as a trap. The contents are afterwards tested Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. for sulphuric acid, L. DE K. Estimation of Total Nitrogen by E. A. Mitscherlich’sMethod. VINCENTSCHENKE (Chern. Zed., 1909, 33, 712-713).--8 reply to Mitscherlich and Herz and Mitscherlich and Merres (this vol., ii, 614). The author prefers his own process (Chem. Zeit., 1896,20, 1032, 1033). The following process is recommended in the presence of any appreciable amount of nitrites : 0.5-2 grams of the substance, and so much potassium chlorate that there is one part of this to three parts of nitrous acid, are placed in a round-bottomed flask, 50 C.C. of water are added, and then drop by drop 3 C.C. of dilute sulphuric acid (1 : 2). After a quarter of an hour, 2-4 grams of reduced iron are added, and then 15 C.C. of the dilute acid (Ulsch’s process), and when the reduction of the nitrate to ammonia is accomplished, the organic substances are destroyed by evaporating with 30 C.C. of sulphuric acid and a few drops of mercury (Ejeldahl method). A blank experiment should be made, once for all, to test the purity of the reagents used. 1,. DE K. Detection of Nitrates in the Presence of Bromides. VILLEDIEC (J. Pharm. China., 1909, 30, 66--67).-When testing for nitrates in View Article Online

700 ABSTRACTS OF CHEMICAL PAPERS.

the presence of a largebexcess of bromides, it is advisable to remove the latter; this can, of course, be effected with silver sulphate, but in practice this is rather inconvenient on account of its slight solubility. The following test is recommended. The liquid, neutralised if necessary, is mixed with a slight excess of basic lead acetate, which precipitates nearly all the bromine, and the filtrate is then heated to boiling and the excess of lead precipitated by adding a little powdered sodium sulphate. To the filtrate the usual test for nitrates with ferrous sulphate and sulphuric acid is then applied. L. DE K. Estimation of Phosphorus in Urine. G.C. MATHISON(Bio-Chem. J., 1909,4,233-239).-The estimation of total phosphorus in urine is best carried out by Plimmer and Bayliss’s modification of Neumann’s method ; and inorganic phosphates by precipitation with magnesium citrate mixture, incineration, and calculation from the weight of the ash .(Mg2P207). Magnesia mixture gives incorrect results, owing to partial precipitation of calcium and of organic phosphorus, Organic phosphoric acid is determined by subtracting the inorganic from the total phosphoric acid, or by applying Neumann’s method after the removal of inorganic phosphates. The uranium acetate method is inaccurate. Organic phosphorus must be estimated while the urine is fresh, as it decomposes in stale urine, especially if ammonia is present. It is readily dialysable. W. D. H. Disappearance of Arsenic in the Form of Gaseous or Volatile Compounds during Putrefaction. MARIOTONEGUTTI (Boll. Chim. Farm., 1909, 48, 259-264, 370-374). -The author’s experiments show that the putrefaction of protein substances containing arsenic is not accompanied by the evolution of arsenical gases,

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. although very small proportions of organic arsenical products having basic or ptomaine characters are formed, which are volatile at a temperature above 30°, probably between 50’ and 60”. The disappearance of arsenic from corpses in the form Df gaseous compounds is hence improbable. 1’. H. J?. Gravimetric Estimation of Boric Acid. KURTARNDT (Chem. Zed.,1909,33,725-726). -The process is intended for the estimation of small qiiantities of boric acid in fused alumina ; 15 grams of potassium hydroxide are fused in a nickel crucible until the mass runs quietly, and, when cold, 3 grams of the impalpable powder are sprinkled over the surface. The mass is now again heated to redness for three hours, the crucible being covered. When cold, the contents are dissolved in water, slight excess of siilphuric acid is added, and the solution is introduced into a Gooch goose-neck apparatus. The authors have slightly modified this apparatus so that it holds fully 150 C.C. The boric acid is then expelled by repeated distillation with methyl alcohol, the distillate is evaporated, as directed by Gooch and Jones (Abstr., 1899, ii, 331), with a known weight of sodium tungstate, and the residue ignited and weighed. When a solution of alumina and boric acid is mixed with ammonia, View Article Online

ANALYTICAL CHEMISTRY. ’101 a portion of the acid is retained obstinately by the precipitated hydroxide. L. DE I(. Estimation of Boric Acid. R. MANDELBAUM(Zeitsch. ano~g. Chem., 1909, 62, 364-369). -The distillation of boric acid with methyl alcohol (Spindler, Abstr., 1905, ii, 480) may be used as an accurate method of estimation when modified. The borate, or substance containing borates, is warmed with 40% phosphoric acid, any carbon dioxide formed expelled by a current of purified air, the flask connected with a condenser, and a receiver containing a known excess of standard sodium hydroxide attached. Absolute methyl alcohol (150-170 C.C. for 0.2 gram B,OJ is run into the flask, which is then heated, a current of air saturated with methyl alcohol being bubbled through it. Finally, the sodium hydroxide flask is warmed to expel methyl alcohol, which distils through a second condensar into a receiver. The sodium hydroxide is then cooled, mixed with half its volume of glycerol, and titrated with sulphuric acid, phenolphthalein being used as indicator. The analysis occupies two to three hours. C. H. D. Elementary Analysis According to Carrasco-Plancher. ORESTECARRASCO (Chsm. Zeit., 1909, 33, 733-734, 755-756).-An improvement of the apparatus described previously (Abstr., 1896, ii, 201). The copper oxide has been replaced by ‘‘platinum biscuit,” and different combustion tubes are used according to the nature of the substauce (solid, liquid, readily volatile, etc). Nitrogen-, sulphur-, and halogen-containing substances may also be analysed by means of the apparatus. L. DE K. Simultaneous Estimation of the Residue and Combined

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. Carbon Dioxide in Waters. K. CHARITSCHKOFF(Chem. Zeit., 1909, 33, 670)-A slight modification of the Rohrbeck-Geissler apparatus for the estimation of carbon dioxide in carbonates from the loss sustained on adding hydrochloric acid. The lower, basin-shaped, part of the apparatus may be removed and weighed, and serves for estimating the residue of the water in the ordinary way. The upper part of the apparatus is then put on, and the carbon dioxide is estimated as usual. L. DE K. Estimation of the Alkalinity of Bleaching Powder Solu- tions. KENNEDYP. ORTON and W. J. JONES(Analyst, 1909, 34, 317-318).--8 known volume of the solution is added to an excess of N/lO-hydrochloric acid contained in a Drechsel bubbler, and a rapid current of pure air is drawn through for forty- five minutes, the solution being i meanwhile carefully shielded from light. After ascertaining that the liquid is free from chlorine by testing a drop with a drop of 0.1% solution of methyl-orange, which should not be bleached, the excess of acid is titrated with N/lO-sodium carbonate. Allowance is then made for acid neutralised by the hypochlorite of the sample. L. DE K View Article Online

702 ABSTRACTS OF CHEMICAL PAPERS.

A New Rapid Volumetric Method for the Estimation of Columbium in Presence of Tantalum, and its Application to the Analysis of Columbium Minerals. FLOYDD. METZGERand C. E. TAYLOR(Zeitsch. anorg. Chern., 1909, 62, 383-394).- Columbium and tantalum could only be separated hitherto approxi- mately by fractional crystallisation of the potassium double fluorides. It is now found that when succinic acid is added to a solution of columbium and tantalum in concentrated sulphuric acid, the solution may be greatly diluted and heated without precipitation taking place. The columbium may then be reduced with zinc and titrated with permanganate, which does not act on succinic acid. The zinc used for reduction should be amalgamated, 0.5 gram of mercury dissolved in 25 C.C. of nitric acid and diluted to 250 C.C. being used for 600 grams of zinc. In making an analysis, 0-2-0-5 gram of the mixed oxides is fused in a platinum crucible with 5 grams of potassium hydrogen sulphate, mixed with 10 grams of concentrated sulphuric acid, heated until dissolved, and cooled. The solution is transferred to a beaker, and the crucible rinsed with 30 C.C. of sulphuric acid. Two grams of succinic acid are added, the whole stirred, and 20 C.C. of a saturated aqueous solution of succinic acid added, with stirring. The solution is made up to 200 C.C. with water, and warmed to '75". The Jones reduction apparatus, packed with amalgamated zinc, is rinsed with 200 C.C. of 5% sulphuric acid at 75", and then filled with 20% acid at the same temperature. The columbium solution is run through the apparatus, which is then washed out with 50 C.C. of 20% acid and 200 C.C. of 5% acid. The brown reduced solution is titrafed with permanganate in an atmosphere of carbon dioxide. One C.C. N/lO-KMnO, = 0*007052gram Cb,O,. The reaction corresponds with a reduction to Cb,0,.,,7. In the analysis of minerals, the volumetric method gives lower values for columbium and correspondingly higher

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. values for tantalum than the method of fractional crystallisation. It is more exact than the latter. C. H. D.

Estimation of Lead in Tinned Utensils, etc. FRANZKNOPFLE (Zeitsch. NaAr. Genussm., 1909, 17, 670).-The usual method of separating lead from tin in alloys by treating the latter with nitric acid and dissolving the lead nitrate from the metastannic acid cannot be employed if the alloy contains much iron, as the ferric nitrate dissolves a portion of the metastannic acid, which ifi re-precipitated with the lend when the latter is estimated as sulphate. The following method is therefore proposed : From 0.5-1-0 gram of the alloy is treated in a porcelain basin with nitric acid, D 1.50 to 1.52, exactly 1 C.C. of the acid being used for each 0.1 gram of metal. The basin is then covered with a clock-glass, and water is added drop by drop until red vapours no longer appear. The excess of acid is next evaporated on the water- bath, so as to leave a moist residue, to which is added a sufficient quantity of hot sodium phosphate solution and about 50 c,c. of hot water. The crystalline precipitate of stannic phosphate is collected on a filter, and the lead is then estimated in the filtrate in the usual way as sulphate. w. P. s. View Article Online

ANALYTICAL CHEMISTRY, 703 Golorimetric Estimation of Lead in the Presence of Iron; Preparation of Lead-free Reagents by means of Ferric Hydroxide. JOHN M. WILKIE (J. SOC.Chem. Ind., 1909, 28, 636-638).-Lead is precipitated completely from its solutions by ammonia provided there is a sufficiency of ferric iron present ; this fact enables lead-free ammonium chloride, etc., to be prepared. When estimating lead colorimetrically in presence of iron with sodium sulphide by Teed's method (Abstr., 1893, ii,'242), the author finds it necessary to reduce any iron to the ferrous state, and this is effected most conveniently by boiling the acid solution with a little sodium thiosulphate until colourless Some potassium cyanide is then added, followed by excess of ammonia. Addition of tartaric acid is superfluous. L. DE K. Precipitation of Copper Oxalate in Analysis. FRANKA. GOOCHand H. L. WARD(Amer. J. Xci., 1909, [iv], 2'7, 448--458).-A study of the best conditions to effect a complete precipitation of copper as oxalate, and containing a large number of experiments, the results of which are tabulated. The best and most convenient procedure for the precipitation of either small or large amounts of copper consists in adding 2 or 4 grams of oxalic acid to 50 or 100 C.C. of the 5% acetic acid solution of the copper salt containing 5 or 10%of nitric acid. The precipitate is afterwards titrated with permanganate in presence of sulphuric acid. L. DE K. The Volumetric Estimation of Mercuric Salts. H. MORAWITZ (Xeitsch. anorg. Chem., 1909, 62, 310-312. Compare this vol., ii, 185).-A reply to the criticisms of Andrews (this vol., ii, 440). C. H. D.

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. Electro-chemical Behaviour of Manganese. 0. NICOLESCU OTIN (Zeitsch. Elektrochem., 1909, 15, 385-386).-1n estimations of mznganese by Engels's method (electrolysis of a solution containing chrome alum and sodium acetate with an anodic current density of 0.006 to 0.01 ampere per sq. cm.), the author used a cathodic current density of about 0.05 ampere per sq. cm., and obtained some 7% of the manganese in the metallic form. He finds that this is prevented by using a low current density at the cathode, or by adding ammonium sulphate (about 2 grams per 100 c.c.) to the solution. T. E. Electrolytic Estimation of Manganese. C. NICOLESCUOTIN (Zeitsch. Elektrochem., 1909, 15, 386-389).-The deposit formed at the anode when a solution of a manganese salt and of ammonium sulphate (1 to 2 grams) is electrolysed, is shown to have the composition MnO, (after drying at 200--220'). Except in very small quantities, however, it does not adhere well to the matt platinum basin used as anode. This difficulty is overcome by adding from 3 to 8 C.C. of alcohol. Quantities up to 1.1 gram of MnO, may be estimated in thig way, using an anodic current density of about 0.04 ampere per sq. cm. at SO0, or 8 or 10 times less at the ordinary temperature. T. E. View Article Online

704 ABSTRACTS OF CHEMICAL PAPERS. Estimation of Iron by Permanganate in Presence of Eydro- chloric Acid. G. CECILJONES and JOHNH. JEFFEBY(Analyst, 1909, 34, 306--316).-The old method recommended by Fresenius gives untrustworthy results. The method proposed by Reinhardt (Abstr., 1890, 296) may, however, be employed advantageously as follows. The iron oxide is dissolved in 23 C.C. of hydrochloric acid, D 1.1, and reduced with as little stannous chloride solution as possible. Ten C.C. of saturated mercuric chloride are then added, and after ten minutes it is poured into 10 C.C. of Reinhardt’s solution and diluted with water to 400 C.C. The liquid is then titrated with standardised permanganate ; it is absolutely necessary that this should be added very slowly, drop by drop. The Reinhardt solution is prepared as follows : 200 grams of crystallised mangsnous sulphate are dissolved in 1000 C.C. of water, and a cooled mixture of 400 C.C. of sulphuric acid and 600 C.C. of water are added, also 1000 C.C. of phosphoric acid, D 1-13, L. DE K.

Reduced Iron, VIRGILCOBLENZ and OTTOB. MAY (Zeitsch.ungew. Chern., 1909, 22, 1224-1227).--8 criticism of the processes in use for the assay of reduced iron, the value of which depends on the percentage of actual metallic iron. The iodine titration process, and the methods based on the use of copper sulphate, are described, and the results communicated in a table. The following process used in steel aualysis seems promising; it is based on the estimation of the oxidised iron and siliceous impurities. One hundred and seventy C.C. of a nearly saturated solution of potassium cupric chloride and 5 grams of citric acid are placed in a flask, and 3 grams of the sample are added. After shaking for some time at a temperature not exceeding 15*5O, the undissolved iron oxides, etc., are collected, washed with cold water, and then with a weak solution of citric acid until free from copper. The mass is then dried, ignited, and

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. weighed as ferric oxide. L. DE I(.

Analysis of Special Steels. J. PmiN LEHALLEUR(illon. Sci., 1909, 23, i, 263).-In the analysis of steels containing molybdenum, vanadium, wolfram, nickel, and chromium, the separation of the first of these metals from the others by means of ether should be carried out in hydrochloric acid solution (D 1.12). The ether is distilled off, and the residue evaporated with sulphuric acid. The warm aqueous extract is treated with hydrogen sulphide, and the precipitated sulphide ignited in a stream of hydrogen sulphide, but not in hydrogen, as this reduces the product to a mlphide lower than that corresponding with MOS,. Vanadium is precipitated in ammoniacal solution as manganese vanadate, and redissolved in concentrated hydrochloric acid. Chromium is reduced from the chromate by ferrous ammonium sulphate, and the excess of this salt titrated with permanganate. Tungsten is estimated by attacking the alloy with concentrated hydrochloric acid, evaporating to dryness twice with nitric acid, and then with hydrochloric acid and potassium chlorate. The residue is dissolved in boiling dilute hydrochloric acid, and the liquid (A) decanted on to an ashless filter; the insoluble residue is treated with boiling dilute ammonium hydroxide, View Article Online

ANALYTlCAL CHEMISTRY. 705

when tungstic acid is dissolved together with a little silica. The liquid is poured on to the preceding filter, washed with dilute ammonium hydroxide, and the liquid collected in another vessel. The ammoniacal filtrate is concentrated, transferred to a tared platinum crucible, and evaporated to dryness with nitric acid until the residue is yellow. The crucible and contents are weighed, treated with hydrofluoric and sulphuric acids, and re-weighed, the loss giving the silica which has been volatilised. The filter paper is ignited and weighed, treated with hydrofluoric acid, and the remainder of the silica thus estimated, The residue is fused with sodiuin hydrogen sulphate, extracted with water, and added to the liquid (A), in which chromium is estimated by one of the usual methods. The nickel (after precipitation as sulphide) is estimated by electrolysis in ammoniacal solution with a maximum current of 4 amperes. F. AT. G. M. Microchemical Reaction of Cobalt ; Nickel and Cobalt Dimethylaminobeneeneazobeneenesulphonates. M. EMMANUEL POZZI-ESCOT(Ann. Chim. anal., 1409,14,207-208). -The nickel compound when crystallised from hot water, in which it is only sparingly soluble, forms lustrous, yellow, hexagonal tablets. Magnesium also yields a similar precipitate, but this becomes crystalline in the cold, and the crystals are smaller than those of nickel. The cobalt compound crystallises both from hot and cold solutions in long, slender prisms, forming long needles of a violet or black colour, often grouped in stars; when obtained from a rapid evaporation, small needles are formed, grouped in palisade-like form. The colour and size distinguish the cobalt crystals suGcieutly from similar crystals of other metals. L. DE K. Estimation of Nickel and Cobalt according to Rosenheim-

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. Huldschinsky. MAX PRITZE(Chem. Zeit., 1909, 33, 694).-This process is based on the fact that cobalt-ammonium thiocyanate is boluble in a mixture of amyl alcohol and ether, whilst the nickel compound is not. When the solution, however, contains 50 or 100 times more nickel than cobalt, a small portion of nickel is also extracted. In order to free the cobalt completely from nickel, the author prefers treatment with dimethylglyoxime to a second shaking with the amyl alcohol-ether mixture. L. DE I(. The Estimation of Vanadium in Steel. EMILE JABOULAY (Rsv. yen. Chim, pure appl., 1909, 12, 143).-This method is based on the fact that when a solution containing hypovanadic acetate and a large excess of ferrous acetate is boiled in contact with air, oxidation takes place and a precipitate is slowly formed which contains the vanadium, iron, and any chromium which may be present.

+ Modifications of the method, which are to be used when chromium, tungsten, molybdenum, or other metals are present, are also described in detail. P. M. G. M. Estimation of Bismuth in Bismuthum Tribromo- phenylicum.” 0.SCIILENK (Pharnt, Zeit., 1909, 54, 538).--0ne to View Article Online

706 ABSTRACTS OF CHEMICAL PAPERS.

two grams of the sample are heated to boiling with 20 C.C. of 10% sodium hydroxide solution until the bismuth hydroxide has separated. The liquid is diluted with water, and after decanting it through a filter, the precipitate is again treated repeatedly with the hot alkali, until this no longer gets turbid on adding hydrochloric acid (absence of tribromophenol), The precipitate is now collected on the filter, thoroughly washed with hot water, and then burnt with the filter in a porcelain crucible. It is then moistened with nitric acid, dried, and once more ignited. L. DE K.

Comparison of the Iodide and Lime Methods for the Estimation of Glycerol in Wine. J. SCHINDLERand H. SVOBODA (Zeitsch. Nakr. Genussrn., 1909, 17, 735-741). -The iodide method described by Zeisel and Fanto (Abstr., 1902, ii, 585; 1904, ii, 95) for the estimation of glycerol in wine was fouod by the authors to be trustworthy and rapid ; the apparatus devised by Stritar (Abstr., 1904, ii, 95) is of considerable use in carrying out the process. The lime method, in the case of dry wines or wines which do not contain more than 5 grams of sugar per 100 c.c., yields concordant results; the latter are, however, somewhat lower than those obtained by the iodide met hod. Possibly the loss of glycerol during evaporation is balanced by the presence of impurities. Preference must be given to the iodide method in the case of sweet wines, as the lime method gives results which are too lorn. w. P. s.

Estimation of Glycogen and Starch; Detection of Horse Flesh in Sausages. MAURICEPIETTRE (Ann. Chim. anal., 1909, 14, 206-207).-Twenty-five grams of the contents of the sausage are boiled in a reflux arrangement with 80 or 90 C.C. of alcoholic potassium hydroxide (aqueous potassium hydroxide, D 1-3,20c.c.; absolute alcohol, Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. 80 c.c.), which removes the fatty and protein matters. The residue is collected on a filter, and washed first with hot 80 vol.% alcohol, and then with cold alcohol slightly acidified with hydrochloric acid until nearly the whole of the alkali is removed. The mass is then heated with slightly alkaline water, which dissolves both starch and glycogen. On adding an equal volume of alcohol, the starch is precipitated, and may be collected and washed with cold 50 vol.% alcohol; the filtrate is then concentrated to a small volume, and the glycogen precipitated by adding excess of absolute alcohol. It may be recognised by its flocculent appearance and brown colour, and by the reaction with iodine in acetic acid solution. If desired, it may be collected, washed with alcohol, dried, and weighed. L. DE E(.

The Estimation of Mineral Acids in Vinegar. FERNAND REPITON(Mom. Sci., 1909, [iv], 23, i, 172).-A criticism of the work published by Richardson and Bower (J. Soc. Chem. Imd., 1906, 25, 836) on the same subject. The author considers his methods simpler and his results quite as accurate as those obtained by the above morkers. F. M. G. M. View Article Online

ANALYTICAL CHEMISTRY. 707

Estimation of Fatty Acids in Soaps. M. DOMINIKIEWICZ (Chem. Zeit., 1909, 33, 728).-Ten C.C. of soap solution (=about 0.5 gram of soap) are decomposed by heating with 10 C.C. of hydrochloric acid on the boiling water-bath for five minutes, and then centri- fugalised for five minutes in a specially constructed apparatus (resembling a butyrometer). The fatty layer is then read off on a scale (temp. 99’) ; each division =0*01 gramof acias. As, however, the sp. gr.’s of the acids are less than that of water, a correction must be applied when calculating the percentage by weight. In practice, the sp. gr.’s of fatty acids used in soap-making may be taken as about 0.835 (temp. 99.). L. DE I(.

Estimation of Lactic Acid in Urine. JOHNH. RYFFEL(Proc. physiol. Xoc., 1909, v-vii; S. Physiol., 39).-The urine is first steam- distilled with rather over 50% of sulphuric acid; the lactic acid then yields acetaldehyde quantitatively. The acid distillate is then just made alkaline and redistilled ; to the distillate, Schiff’s reagent (rosaniline hydrochloride bleached with sulphur dioxide) is added, and the depth of colour compared by a colorimeter with that obtained with the reagent and standard formaldehyde solution. W. D. H. Reactions of Oxalates. TARAKNATH DAS (Chem. News, 1909, 99, 302).-For the analysis of salts containing oxalates, the following method is advocated as being more expeditious than the usual operation of ignition. The precipitate obtained in the course of analysis by adding ammonium chloride and ammonia is dissolved in nitric acid, and the decomposition of all oxalates and their conversion into nitrates is effected by adding excess of potassium chlorate and boiling for a few minutes. Oxalates may be detected when in presence of carbonates, sulphites,

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. etc., by treating the mixture with dilute nitric acid until the evolved gas no longer renders lime water cloudy (separation from carbonates), adding excess of potassium chlorate, and again boiling; if the lime water is now turned cloudy, the presence of oxalate may be inferred. J. V. E. Estimation of the Volatile Organic Acids of Tobacco and the Behaviour of the Oxalio Acid. RICHARDKISSLING (Chem. Z&., 1909, 33, 719--720).-A criticism of Tdth’s method (Abstr., 1908, ii, 238, 330; this vol., ii, 446). Tdth’s statement that malic, citric, and oxalic acids yield an acid distillate on boiling with addition of sulphuric acid is erroneous. Oxalic acid is not decomposed on repeated evaporation with water, but the dry residue on being heated at 100’ gradually volatilises by sublimation. When malic and citric acids are also present, the oxalic acid is but very imperfectly expelled. Acetic acid, if present, may be readily got rid of by heating on the water-bath until the odour is completely gone. L. DE K. Detection of Benzoio Acid in Foods. Mlle. ANNAJONESCU (J. Pharm. Chim., 1909, [vi], 30, 16--17).-1n b private communication to the author, Leys has claimed priority for the discovery of the View Article Online

708 ABSTRACTS OF CBEMICAL PAPERS.

hydrogen peroxide test for benzoic acid, described recently by the author (this vol., ii, 627). Leys' memoir (Abstr., 1901, ii, 488) only gives precise directions for the detection of '' saccharin " by this metbod, and the author's object was to indicate that benzoic acid could be readily isolated from foods containing it and be detected by this test. T. A. H. Detection of Benzoic Acid in Meats and Fats. KARL FISCHERand 0. GRUENERT(Zeitsch. Nahr. Genussm., 1909, 17, 721--734).-1n the method proposed, the benzoic acid, after it has been extracted from the substance under examination, is converted in part into salicylic acid by fusion with sodium hydroxide, and the presence of the latter ascertained by the well known coloration produced with ferric chloride. Fifty grams of the finely divided meat, or molten fat, are well mixed with 100 C.C. of 50% alcohol, acidified with sulphuric or hydrochloric acid (in the case of fats, the use of 20% alcohol is recommended) ; the alcoholic solution is then separated, rendered alkaline, and evaporated until the alcohol has beexi removed. The residual liquid is diluted to a volume of 50 c.c., 5 grams of sodium chloride are added, the mixture is acidified with sulphuric acid, heated to boiling, cooled, and extracted with ether. The ethereal extract is evaporated, the residue is fused in a silver crucible with a little sodium hydroxide, and the fused mass is dissolved in water. The solution obtained is acidified with sulphuric acid, extracted with ether, and the residue obtained on evaporating the ether is tested with a drop of 0.5% ferric chloride solution. The method will detect the following quantities of benzoic acid : in fresh meat, 0.01%; in smoked meats, 0.02%; in lard, butter, etc., 0.005%. The test described by Brevans (Abstr., 1902, ii, 112) is stated to be useless for the detection of benzoic acid in meats and fats. Tests which are based on the con-

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. version of benzoic acid into benzaldehyde are capable of detecting the presence of 0.04% of the acid in fresh meats, but not in smoked meats ; they are unsatisfactory in the case of fats, w. P. s. The Sohardinger Reaction for Milk. KURTSCHERN (Biochem. Zeitsch., 1909, 18, 261-284).-Schardinger has shown that milk at 45' decolourises a reagent containing methylene-blue and formaldehyde. This reaction is apparently due to the presence of an enzyme, as it is not produced if the milk is boiled previously. The author shows however, that the Schardinger reaction is not produced by all milks. Milk from cows in the earlier stages of lactation is inactive. The activity, however, increases with the stage of lactation, and i8 generally given with milk from cows in the later stages. For these reasons, the Schardinger reaction must be applied with care to milk examined for hygienic purposes. S. B. S. The Quantitative Estimation of Diphenylsmine. DREUER (Zeitsch. ges. Schiess, Xprengstofwesen, 1909, 4, 123).- When diphenylamine is brominated in alcoholic solution, tetTabromodiphenyZ- arnine, red needles, m. p. 102", is precipitated on the addition of water. It is insoluble in water, sparingly soluble in alcohol, but soluble in the View Article Online

ANALYTICAL CHEMISTRY. 709 ordinary organic media. The quantitative estimation is carried out as follows. An alcoholic solution of commercial diphenylamine is slowly treated with an excess of bromine in alcohol until no further precipitate is produced. About twice the volume of water is added with stirring, and the mixture heated until the alcohol and excess of bromine are removed and the precipitate becomes granulated ; this is collected in a tared Gooch crucible, washed with warm water, and dried at 98-100°. . F. 15. G. I@. Estimation of Urea in Urines. PHCEBUSA. LEVENEand GUSTAVEM. MEYER(J. Amer. Chem. Soc., 1909, 31, 717-722).-An objection to Benedict and Gephart’s method (this vol., ii, 103) is the partial hydrolysis of the uric acid and creatinine by the hydrochloric acid at 150’. The authors overcome the difficulty by removing the basic substances by means of phosphotungstic acid. In the modified method, 12.5 C.C. of urine are placed in a 50 C.C. flask, and a 10% solution of phosphotungstic acid in 10% sulphuric acid is added slightly in excess of the amount required to precipitate the basic substances. After twenty-four hours, the volume is made up to 50 C.C. with 10% sulphuric acid. The solution is filtered, and 20 C.C. of the filtrate are heated in an autoclave as in Benedict and Gephart’s method. c. s. Isolation of Conium Alkaloids from Animal Tissues. WALTER J. DILLING(Bio-Chem. 1909, J., 4, 286--299).-The most satisfactory method for the isolation of coniine from animal tissues to which it has been added is that of distillation. Coniine appears to be decomposed both by the action of living cells and during putrefaction. Con- hydrine and +-conhydrine can be isolated by extraction with alcohol and precipitation by phoephotungstic acid, but the results are inconstant.

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. W. D. H. Factors which Influence the Estimation of Creatinine. F. C. COOE(J. Arner. Chem. Xoc., 1909, 31, 673-693).-Folin’s colori- metric method for the estimation of creatinine (Abstr., 1904, ii, 375) gives satisfactory results for the total creatinine in beef extracts and similar products, but is not trustworthy for the estimation of the original creatinine in meat products. After a brief historical discus- sion of the colour reaction which takes place when a creatinine solution is treated with picric acid and an alkali, the author tabulates the results of experiments on solutions of meat extract, creatine, and creatinine to ascertain what is the influence on the colour of the amount of picric acid and of alkali, and also the influence of dilution, of keeping, of coagulable proteins, and of proteoses and peptones. The results show that in all cases in Folin’s method it is desirable to take 25 or 30 C.C. of 1.2% picric acid solution, and 10 C.C. of 10% sodium hydroxide. The values for creatine and creatinine, alone, in meat, or in meat extract, are lowered by dilution; the error appears to be fairly constant, and averages 0.00019 gram of creatinine per 10 C.C. of dilution. Before taking readings, the solution should remain five minutes after adding the reagents. The presence of coagulable View Article Online

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protein, or of proteoses and peptones, lowers the values for solutions containing ciwatine, creatinine, or meat extract. The autoclave method of Benedict and Myers (Abstr., 1907, ii, 492), modified so as to be applicable to meat products, gives the most satisfactory results in estimating creatine. c. s. New Reactions of Hydrastine, Hydrastinine, and Narco- tine. A. LABAT(Bull. Xoc. chim., 1909, [iv], 5, 742--743).-When 0.1 C.C. of solutions of hydrastine (0*33%), hydrastinine (1%), or narcotine (1%) in 10% sulphuric acid is added to 2 C.C. of sulphuric acid, and the mixture heated on a water-bath with 0.1 C.C. of solutions of certain phenols, very beautiful colorations are produced. With a 5% alcoholic solution of gallic acid, the colour is an intense emerald- green, which gradually becomes blue. The absorption spectrum of the liquid exhibits bands in the red and between the red and yellow, the latter of which disappears more quickly on dilution. The solution when diluted with glacial acetic acid becomes violet. With a 5% guaiacol or catechol solution, a currant-red colour is first developed, which becomes violet. Finally, in the case of a 2% solution of morphine hydrochloride, the mixture gradually becomes violet. The reaction with gallic acid is the most sensitive, being recog- nisable with 1 part of hydrastinine, hydrastine, or narcotine in 50,000, 40,000, or 20,000 parts of water respectively. The reactions confirm the close analogies supposed to exist between the constitution of the three alkaloids. E. H. New Reactions of Opianic Acid and their Applications to the Detection of Hydraatine and Narcotine. A. LABAT(Bull. Soc. chinz., 1909, [iv], 5, 743-745. Compare preceding abstract).- When a sulphuric acid solution of hydrastine or narcotine is oxidised

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. with potassium permanganate, appreciable quantities of opianic acid are produced. By adding 0.1 C.C. of a 1% alcoholic solution of the latter acid to 2 C.C. of pure sulphuric acid, and treating the mixture with 0.1 C.C. of a solution of certain phenols, colorations are obtained. With a 5% solution of gallic acid a blue coloration is produced, and changes to the colour of dead leaves on heating on a water-bath. A 5% alcoho1ic:guaiacol solution gives a currant-red colour, which changes to an intense blue on the water-bath, whilst the absorption spectrum of the solution then has bands in the red, between the red and the yellow, in the green, and between the green and the blue; these disappear on dilution in the reverse order to that in which they are given. Similar colorations are obtained with catechol. Similarly, with 20% alcoholic solutions of a- and P-naphthol, currant-red and wine-red colours are produced respectively. A 5% alcoholic solution of codeine gives a violet coloration which gradually changes to blue on a water- bath. An intense violet tint, becoming paler on the water-bath, is obtained with an alcoholic solution (2.5%)of P-methoxynaphthalene. E. H. Estimation of Quinine and its Excretion in the Urine. M. NISRI(Arch. exp. Path. Pharm., 1909,60, 31 2--323).-Acid quinine View Article Online

ANALYTICAL CHEMISTRY. 711

citrate (C,,H,402~2,C,H,07) can be prepared by saturating quinine with citric acid in ethereal solution, and the preparation of this compound renders the estimation of quinine an easy matter. In the urine, the quinine is first extracted with ether after the urine is made strongly alkaline. About 34.5% of the quinine given is recoverable in the urine, and the greater part of this (25.5%) is excreted during the first twentyfour hours. If the quinine is given by the mouth ia combination with arsenic or iron, the absorption and excretion of quinine are not affected. W. D. H. Micro-chemical Detection of Alkaloids, particularly in the Leaves of Pilocarpus pennatifolius. 0. TUNMAN(Chem. Zentr., 1909, i, 1510-1511 ; from Schweix. Woch. Chem. Pharm., 1909, 47, 177--183).-The reagents are applied directly to the cells. Zinc chloride-iodine forms dark black droplets, which exhibit rapid motion, but dissolve after fifteen minutes. The disadvantage of this test is that the strong cellular walls of the epidermis is also attacked. If the preparations are soaked for a few seconds in a drop of dilute nitric acid (1 : 5) and then placed on another object glass with a little absolute alcohol, a crystalline deposit of pilocarpine nitrate will be noticed. When moistened on a slide with potassium mercuric iodide, and then with a few drops of hydrochloric acid, a grey, amorphous precipitate is formed. Solution of iodine in potassium iodide (1 part of each to 200 parts of water) causes in the pilocarpine-containing cells numerous dark brown or reddish-brown, lustrous, oily droplets, which unite to larger drops and then soon disappear. With slightly acidified iodine solutions, finely granulated masses are obtained. The same occurs with potassium bismuth iodide, but the precipitates are then of a bright red colour. The author describes how the pilocarpine alkaloids are distributed.

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. In the inner tissues some cells give decided reactions for alkaloids, whilst neighbouring tissues do not contain a trace. L. DE I(. A New Method for Detection of Indole in Culture Media. G. MORELLI(Zentr. Bakt. Par., 1909, i, 50, 413-415).-IndoIe gives a red coloration with oxalic acid. The test for indole is carried out by hanging a piece of filter paper, which has been dipped in saturated oxalic acid and then dried and sterilised, just above the culture medium. S. B. S.

Detection of Coal-tar Colours in Wine by means of the Reaction between Iodine and Tannin. CARLOCONTI (Boll. Chim. Parm., 1909, 48, 295--298).-A solution of tannin absorbs iodine, giving a liquid which does not react with starch paste, and, if not saturated with iodine, does not evolve iodine when distilled almost to dryness. When iodine is added to a red wine, all the natural colouring matter of the latter is precipitated, the reaction proceeding rapidly and completely in the warm. This reaction is applied to the detection of coal-tar dyes in wines, the procedure being as follows. One hundred C.C. of the wine are freed completely from alcohol by evaporation, the cold residue being made up to the original volume View Article Online

712 ABSTRACTS OF CHEMICAL PAPERS.

with water. To the liquid, heated at 40--50° on a water-bath and shaken, a 2% solution of iodine in potassium iodide solution is added until, on testing with starch paper, the coloration does not remain constant. The solution is heated in a water-bath so long as the precipitate does not become flocculent or assume an orange-red colour ; it is then left for three to four hours and filtered. To 10 C.C. of the filtrate is added, drop by drop, a slight excess of sodium thiosulphate solution. Natural wine then appears pale yellow, whilst wine coloured artificially with an acid dye is rendered more or less red ; the latter dour becomes more evident if the acid of the wine precipitates free sulphur from the excess of thiosulphate. In this way 1 part of colouring matter per 100,000 of wine is rendered evident. Should the coloration be doubtful, a thread of fat-free wool is boiled for twenty minutes in a portion of the residual liquid acidified with a few drops of hydrochloric acid. The wool is removed, well washed, and gently heated in dilute sodium thiosulphate solution. With a natural wine, the wool then has a yellow colour, whilst with a wine artificially coloured, it has a distinct red colour. This modification detects 1 part of colouring matter per 400,000 of wine. T. H. P. Detection of Urobilin in Urine. P. GuIGuEs(Cihern. Zelztr., 1909, 1, 1273; from BuU. 8ci. Pharm., 1909, 16, 88--89).-The author proposes to precipitate the urobilin by saturating the urine with ammonium sulphate af her acidification with hydrochloric acid. The precipitate is washed with a saturated solution of ammonium sulphate, dried in a vacuum over sulphuric acid or calcium oxide, and then extracted with hot ethyl acetate. The solution which contains the urobilin is examined spectroscopically. The chief absorption bands lie between green and blue from X=502-482 or 501-483. If zinc acetate is added, the bands move towards h=517-497.

Published on 01 January 1909. Downloaded 24/10/2014 13:06:11. L. DE I(. Estimation of the Oxidation Numbers of Urine with potassium Permanganate. HrLm (Chern. Zelztr., 1909, 1,1201 ; from Apoth. Zeit., 1909, 24, 146--147).-The oxidation number of a urine is the number of mg. of oxygen absorbed by 1 C.C. of the sample. The operation, which is the same as in the Kubel process for the estimation of organic substances in water, is carried out as follows : 10 C.C. of diluted urine (10 grams : 100 c.c.) are mixed with 50 C.C. of water and 25 C.C. of dilute sulphuric acid (1 : 2), and heated to boiling, N/lo-Permanganate is then added until the liquid is dark red, and the heating is continued for ten minutes. To the solution, which must still be decidedly red, 10 C.C. of N/lO-oxalic acid are added, and then, again, permsnganate until the liquid is permanently coloured after ten minutes boiling. The oxidation numbers of normal urines seem to lie between 4 and 11. Diabetic and other abnormal urines absorb from 13-14 mg. of oxygen. L.DEE. b