FUNDAMENTAL REVIEW OF DEVELOPMENTS IN ANALYSIS
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Volumetric and Gravimetric Analytical Methods for Organic Compounds
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I
WALTER T. SMITH, JR., WILLIAM F. WAGNER, and JOHN M. PATTERSON University o f Kentucky, Lexington, K y .
T
HE analytical methods described in the following pages are selected from the literature which has become available to the reviewers from October 1953 to November 1955. An effort has been made to present only methods that show a reasonable indication of being of real value. The ultimate test of the value of the methods described here !vi11 be their usefulness in future applications. I n covering the literature of recent years it will be observed that the use of ion exchange resins has been, and continues to be, an important adjunct to analytical chemistry. The titration of cationic detergents with anionic detergents (and the reverse), in which the indicator is equally distributed between an organic and aqueous phase a t the end point, continues to receive study and application. The determination of various organic compounds by oxidation x i t h ceric solutions also continues to be investigated.
-4similar method is reported for the microdetermination of halogens (126). Ethylene dibromide and ethylene chlorobromide in air may be absorbed in ethyl alcohol and decomposed with sodium hydroside, and the liberated halide determined by the T'olhard titration ( 7 2 ) . Chromous ion will react quantitatively s i t h carbon tetrachloride and chloroform by replacing all the chlorine with hydrogen. After the reaction, the excess chromous ion is titrated with fenic alum using thiocyanate as the indicator ( 7 4 ) . The chromous ion reagent is prepared by reduction of potassium dichromate in a liquid zinc amalgam reductor. .4 method for the combustion of organic compounds containing fluorine is carried out with oxygen in a quartz tube with auxiliary external heating, followed by a secondary combustion zone utilizing gas or hvdrogen with excess oxygen. The gas is passed at a rery high velocity, which practically eliminates corrosion of the quartz. The fluorine is converted to hydrogen fluoride, which i3 absorbed quantitatively in 1N sodium hydroxide (165). Belcher ( I S ) has found that a bed of sodium fluoride heated to 270" is more satisfactory than lead chromate for the absorption of silicon tetrafluoride. After recovery of the fluorine, the gravimetric determination as PbClF is more exact than the titration with thorium nitrate. A procedure is also suggested for determining the four halogens in a single sample. A method for the rapid determination of silicon and halogens i q described (62), wherein the sample is fused uith a mixture of ethylene glycol and sodium peroxide in a metal bomb. The fusion product is dissolved in water, boiled to remove hydrogen peroxide, acidified v-ith nitric acid, and then neutralized n ith ammonia solution. An ammoniacal suspension of zinc oxide i q added and the precipitate is filtered and ignited. The silica i n the residue is determined by the usual procedures. Chlorine, bromine, and iodine are determined by conventional methods : the fluorine is determined by precipitation as calcium fluoride or by titration with zirconium tetrachloride. rln automatic combustion apparatus for the determination of sulfur and halogen is described in which the sample is vaporized in a streani of nitrogen, and oxygen is injected in a high temperature zone for combustion. A thermocouple senses the hent generated by the combustion and controls the amount of heat for vaporization. An operator can complete 15 to 25 analyses in a n 8-hour day with virtually no possibility of losing an analysiq from improper combustion ( 1 6 4 ) .
DETERMINATION OF ELEMEXTS CARBON AND HYDROGEN
The total carbon of several organic compounds in aqueous solution was determined with an accuracy within f 401, by treatment of the acidified solution with potassium persulfate in the presence of silver nitrate. The liberated carbon dioxide is passed through an upright condenser and absorbed in weighed Ascarite tubes. A second treatment is necessary and precautions must be taken to prevent absorption of carbon dioxide from the air (60). The product obtained by the thermal decomposition of silver permanganate has several unusual properties which make it useful as a combustion catalyst in the determination of carbon and hydrogen in organic compounds. The combustion is carried out at 450" C. and requires 1 hour for a seniimicroanalysi~. The advantages of the new filling are claimed to he the easy standardization of the catalyst, which may be wed nithout previous testing. and the long catalyst life of 100 analyses. A deviation of 2~ 50" from the 450" combustion temperature still gives good results. The catalyst also absorbs sulfur dioxide and the halogens (79). Tritiated organic compounds may be analyzed by combustion in oxygen, absorption of the resulting water, and determination of the tritium with a Geiger counter. The method gives sufficiently accurate results to make tritium appear useful as a tracer element. The method may also he used for the determination of carbon-14 (161 ).
filETA L S
-4simple, rapid titrimetric method for determination of tetraethyllead is described by PIlilner and Shipman ( 9 4 ) . After the extraction of the lead by hydrochloric acid in the usual way, the lead is titrated at p H 10 in ammoniacs1 tartrate solution with disodium ethylenediamine tetraacetate jdisodium(ethy1enedinitri1o)tetraacetate 1.
HALOGENS
Sodium or lithium diphenyl in ethylene glycol dimethyl ether is used t o decompose both aliphatic and aromatic halides. Follon-ing extraction with water, the halides can be determined by ordinary procedures. The reagent can be used after 1 year vhen stored a t 5" in bottles with foil-lined caps (83). Mikl and Pech (93) modified their method for determination of halogens and sulfur by impregnating filter paper ivith a solution of the compound instead of wrapping the conipound in the paper before burning in a bottle of oxygen.
YITROGEN
The Kjeldahl method continues to be the object of a great amount of careful research, which seems to emphasize the importance of the method for the determination of nitrogen.
706
V O L U M E 2 8 , NO. 4, A P R I L 1 9 5 6 Bradstreet (21) has published an excellent review of the Kjeldahl method from 1939 to 1953 to supplement his previous review. The review discusses the digestion, catalysts, distillation, and determination of ammonia, as well as application to more complicated forms of nitrogen. Bradstreet ( 2 2 ) also presents a study of the determination of nitro nitrogen by the Kjeldahl method. Increasing the digestion temperature by using 18 instead of 10 grains of potassium sulfate gave the best results. -4study of various hydroxy cornpounds which help in the conversion of nitro groups showed that 1naphthol-pyrogallol (1 to 1 mixture) galre the best results and v a s superior to salicylic or thiosalicylic acid. I n a joint study by 27 collaborating laboratories on fei tilizer, feed, and S-benzylthiouronium chloride samples, it was found that mercury is superior to copper as a digestion catalyst and that standard acid is preferable to boric acid for the absorption of ammonia. Certain sections of the .4OAC "Official Methods of Analysis" (7th edition) have been revised as a result of the study (12).
I n a series of papers on the Iijeldahl method, Takeda and Senda (154) report the results of a study of digestion conditions in which a mixture of selenium, mercury oxide, and copper sulfate with sulfuric acid and potassium sulfate catalyzed effectively the digestion of amino compounds but gaye low results n ith nitro compounds. The addition of glucose in the absence of mercury oxide was effective for nitro compounds except volatile stable substances such as 2,5-dichloro-l-nitrobenzene. A pretreatment of nitro compounds with potassium hydroxide and ethyl alcohol appeared to improve the analysis of mononitro compounds but failed for di- and trinitro compounds. ,4 method is described by Datta (33) for determining nitrogen in protein and nonvolatile nitro compounds by heating a finely divided sample Tvith a large excess of a 3 to 1 calcium oxidesulfur mixture. The nitrogen is reduced to ammonia, Ivhich is determined in the usual way by absorption in acid. OXYGEN
A modified Unterzaucher procedure for determining combined oxygen in sulfur-containing conipounds uses a roll of copper gauze a t 900" to remove sulfur as recommended by Oita and Conway (101). A bed of equal parts of carbon and platinum converts oxygen to carbon monoxide a t 900" instead of 1200'. The fillings may all be in a tube in the same furnace (102). SULFUR
I n a variation of the usual methods, the sulfate solution obtained by nitric acid oxidation of the sample is treated with barium chromate. After the barium sulfate is renioved by filtration, the excess chromate in the filtrate is titrated n i t h 0.05-V ferrous solution (156). When tri- and tetramethylenethiourea are oxidized by nitric acid in an open vessel, sulfur values are too low because volatile carbon oxysulfide is formed. If the fumes from the oxidation are passed through a combustion tube over platinum catalyst a t 500' the sulfur from the carbon oxysulfide is oxidized to sulfur trioxide, absorbed, and determined as sulfate (144). -4method for the determination of sulfur in some plant and animal material is described, in which the sample is dissolved in a solution of sodium hydroxide, evaporated to drynees, and heated gradually n-ith the addition of potassium chlorate. The resulting sulfate is determined gravimetrically (147). Sulfur in organic compounds and fuel is determined by burning t h e sample in a stream of oxygen using amorphous chromic oxide as a catalyst (38). An improvement in a quartz tube combustion method for small amounts of sulfur is reported. Ceria on alumina when used as a catalyst is not affected by chlorine. The sulfate formed in the absorbers is precipitated with a known amount of barium
707 chloride and the excess barium ion is titrated with disodium ethylenediamine tetraacetate (166). -4semimicromethod for the determination of sulfur is based on the hydrogenation of the compound in a porcelain tube in the presence of a platinum spiral heated to 850' by an electric furnace. The liberated hydrogen sulfide is absorbed in a buffered zinc sulfate solution, an excess of 0.02.V iodine is added, and the excess is determined by titration with 0.02N sodium thiosulfate. Compounds containing phosphorus poison the catalyst (170). Sulfur is determined in coals, coke, and organic substances by reduction with zinc vapor. The sulfide is liberated as hydrogen sulfide with hydrochloric acid, and determined by titration n ith iodine after absorption in a solution of cadmium acetate (80).
FUNCTIONAL GROUPS ACIDS
-4nhj-drous pyridine has been used as the solvent in the titration of formic and benzoic acids (158). The titrants, piperidine, ammonia, and diethanolamine, n ere employed 1%ith a bromothymol blue indicator. An improved method of determining citric acid (51) invoh-es its precipitation as the lead salt, conversion of the salt to lead chromate, and the iodometric determination of the chromic acid produced upon treatment with hydrochloric acid. Interfering proteins can be removed with trichloroacetic acid or phosphotungstic acid. Oxidative schemes for the analysis of acids have been limited to specific determinations. Thus, lactic acid is oxidized by ceric sulfate (85)to acetaldehyde, which is absorbed in buffered sodium bisulfite, the excess bisulfite being estimated iodometrically. The acceleration of the lead tetraacetate oxidation of formic acid (105) to carbon dioxide by potassium acetate renders the reaction suitable to a manometric method. The conversion of salts of organic acids to the free acid by ion exchange resins (160), followed by neutralization, permits the determination of salts. I n the application of such a procedure to calcium gluconate (163),it was found that stabilizers present in the sample affected the results or else rendered the method useless. Acetates of calcium, magnesium, zinc, manganese, lead, and mercury (31) can be determined by using nonaqueous media. The salts are titrated in mixtures of ethylene or propylene glycol and a higher molecular weight alcohol, hydrocarbon, or chlorinated hydrocarbon, using perchloric or hydrochloric acid and a thymol blue indicator. ACID ANHYDRIDES
The method of Hogsett, Kacy, and Johnson (60) for the determination of chrysanthemum acid anhydride in commercial allethrin has been extended to seven other anhydrides (65). Results are precise and accurate over a wide range of concentrations; most anhydrides react within 5 minutes. The titration of iV-carboxy-a-amino acid anhydrides (16) with sodium methoxide and a thymol blue indicator can be accomplished to within 2% of the equivalence point using the following solvents: methanol, benzene-methanol, acetophenone, dimethylformamide, pyridine, aniline, butylamine, acetone, ether, dioxane, chloroform, and ethyl acetate. A LCOHO LS
The conversion of water-soluble alcohols to the insoluble nickel xanthate salt has been used as a basis for analysis ( 4 ) . The nickel in the salt is determined by titration with ethylenediaminetetraacetic acid. The use of propionic anhydride as a reagent for the estimation of hydroxyl groups in primary, secondary, and tertiary alcohols, polyols, and sterols has been described by Pesez (106). The method appears to have some advantage over acetyl numberp,
ANALYTICAL CHEMISTRY
708 since the propionyl numbers of certain tertiary alcohols are correct t'o within 3% of the calculated value. Oxidation procedures for both ethyl alcohol ( 7 ) and isopropyl alcohol (43) have been described. The ethyl alcohol is oxidized to the aldehyde with a potassium dichromate-potassium sulfate reagent, the excess being determined iodometrically; the isopropyl alcohol is oxidized to acetone, which is absorbed in escess hypoiodite. The excess iodine is titrated and the amount of acetone calculated. h n alkaline solution of potassium cyanide has been employed by de Jong (68) in the determination of methylol groups in the condensates of urea and formaldehyde. The escess cyanide is titrated with mercuric nitrate. The method is superior to the sodium hypoiodite procedure when the polymer contains easily oxidizable groups. Similar procedures have been reported for the periodic acid determination of glycerol, the principal variation being the method used to estimate or destroy the excess perioate. I n one method (114), the excess periodic acid is treated with potassium iodide, followed by titration of the liberated iodine with sodium thiosulfate, while in another ( 3 7 ) , the excess periodate is destroyed by reaction with ethylene glycol. Hartman (58) indicates that the reaction time for the oxidation of glycerol is less than previously believed, and recommends the use of potassium dimesoperiodate, KJ208, for the oxidation of large samples of glycerol because of its greater solubility in water. ALDEHYDES AND KETONES
h modification of the argentometric procedures of Ponndorf (109) has been found useful for the determination of pure alde-
hydes and mistures of aldehydes and ketones (132). i l n accuracy ivithin i 27, is obtained with pure aldehydes. The main disadvantages of the procedure are the difficulty in detection of the end point, and interference by cyclohesanone, cyclopentanone, and pol>-hydroxy alcohols. The hydrosylamine hydrochloride procedure has been estended and adapted for the determination of carbonyl groups in oxycellulose ( 1 4 2 ) and of high molecular weight aldehydes and ketones in the presence of free carboxylic acids (91). Johnston (67J describes a modification of the procedure which avoids acetal formation and involves the use of tert-butyl alcohol. The procedure is recommended for aldeh!-des and ketones which react a t room temperature. The cyanohydrin reaction has been extended to the determinaation of acetaldehyde and propionaldehyde (148). The determination of aldehydes by the bisulfite method followed by iodometric estimation of excess bisulfite has been evaluated (86). The most important modification in the procedure involves the use of a phosphate buffer in the aldehyde-bisulfite reaction (119, 120). Applicat'ions of the method to compounds such as metaldehyde (126) and various mixtures such as acetaldehyde in vinyl acetate (70)and acetaldehyde in the presence of crotonaldehyde (136) have been successful. T h e reaction of phenylhydrazine or substituted phenylhydrazines with aldehydes and ketones is the basis of several methods of analysis. The following titrimetric procedure has been described (157). T o a measured volume (8 to 15 ml.) of a 2.5% solution of phenylhydrazine hydrochloride in 3 :5 aqueous pyridine, add a 0.05- to 0.16-gram sample, stopper the flask, allow to stand several hours in the dark ( a blank is run simultaneously), and titrate the excess phenylhydrazine rapidly with 0.1 to 0 . 2 5 cupric acetate, after addition of 5 to 7 ml. of ether. The end point is the color change from yellow-brown to brown-green. The cupric solution is standardized iodometrically. Meper (98) recommends the use of Orange-G or Chromazon Red A as indicators in the titration of aldehydes or ketones in the presence of sodium acetate with phenylhydrazine hydrochloride. Orange-G appears to be the better indicator, as the color change is more easily recognized.
Another similar procedure (169) involves the use of 2,4-dinitrophenylhydrazine in hydrochloric acid : The amount of hydrazine is determined before and aft,er reaction by azotometric methods. h gravimetric procedure for the determination of the carbonyl group has been applied to allethrin (55). The 2,4-dinitrophenylhydrazone is separated from the other components by chromatography and weighed. The condensation of aldehydes with cornpounds containing active hydrogens has been applied to the gravimetrir determination of aldehydes and ketones. Spencer and Henshall (139) present kinetic data for the dimedone-formaldehyde reaction, Fvhich enable calculation of optimun; conditione for the anal? Cyclohexanone can be determined by condensation wit,h or furfural ( 2 5 ) . piperonal, anisaldehyde (H), Other ketones to which the method has heen applied using anisaldehyde include tert-butgldimethylacetophenone and 1,3-dimethyl-2-acetyl-4,6-dinitro-5-tert-butylbenzene (18). Both 01- and B-diketones may be determined by reaction with bromine; the excess is determined idonietrically (95). T h e authors discuss the effect of mercuric sulfate as a catalyst, the nature of the reactions consuming the bromine, and the behavior of several ketones under these conditions. Derivatives of the aldehydes and ketones may be analyzed 1))application of a n appropriate procedure. acetals, after hydrolysis to the aldehyde with 2 S sulfuric arid. are estimated b!- the method of Siege1 and Weiss (132). Schiff bases can be titrated quantitatively in glacial acetic. acid with perchloric acid, using methyl violet as the indicator (421.
Sant (121) reports that a method employed for the analysis of alkaline solutions of hydroxylamine may be useful in the deter-. mination of oximes. Hydrosylamine is oxidized to nitrogen with ferricyanide and the ferroc>-anideproduced is titrated with ceric sulfate. Oximes and semicarbazoncs can be determined gravimetricallj(98) after an exchange reaction with 2,4-dinitrophenylhydrazine. AMIDES
The reduction of amides and substituted amides to amines b>lithium aluminum hydride 2RCOSR2 Li.ilH, 2RCHJR1 LihlO?
+
+
is the basis of a method of amide determination (135). Steam distillation of the amine from the reaction mixture is followed by titration with standard acid. The hydrolysis of ethyl- and isopropylphenylcarbamates by acid or base to form aniline can be utilized in the analysis of these compounds (11). The aniline is estimated by titration with standard sodium nitrite solution, using a starch indicator. Thioamides can be determined by the sodium hypoiodite titration method (168) or by the peroxide oxidation method of Kitamura ( 7 5 ) . Bromometric methods fail. llethods of analysiz applicable t o derivatives of dithiocarbamic acid,
s
// RSC-SRq I depend largely upon their structures. Compounds with secondary nitrogen can be estimated by the sodium hypoiodite method, bromometrically, or gravimetrically by oxidation with nitric acid or alkaline hydrogen peroxide followed by precipitation of the sulfate formed. Compounds with tertiary nitrogen require more vigorous oxidation procedures. AMINES
Several of the procedures available for the determination of amines involve a perchloric acid titration of the free amine or ita derivatives in nonaqueous media.
V O L U M E 28, N O 4, A P R I L 1 9 5 6
709
I n one such method (159) malachite green, gentian violet, jaframine, and orange I were found to be useful indicators in a 98 to 98.8% formic acid solvent. Owens and Maute (103) recommend the use of acrylonitrile as a solvent for the determination of strong organic bases using a bromothymol blue indicator. Weak organic bases are best titrated using a 1 t o 1 acrylonitrile-acetic acid solvent and crystal violet as the indicator. Both procedures are rapid and reliable; neither requires a blank correction. Aminophenols and various alkaloids ( 3 2 ) may be titrated in ethylene or propylene glycol and a higher alcohol, hydrocarbon, or chlorinated hydrocarbon solvent mixture using a thymol blue indicator. Perchloric acid in an acetic acid-acetic anhydride mixture can be used t o titrate amine picrates (28) to a n accuracy n-ithin 1%. A glacial acetic acid solvent is used along with a methyl violet indicator. Complex formation between tellurium tetrabromide and organic nitrogenous bases is the basis of a titrimetric procedure for amine determination (36). Compounds such as diethylamine, aniline, pyridine, and piperidine Lvere determined to within 1 % of the equivalence point in glacial acetic acid, using concentrated alcoholic solutions of cupric chloride or cobalt bromide as indicators. F a t t y acids and alcohols do not interfere. Solutions of aromatic amines, such as aniline, 0- and p-aminophenol, and 1- and 2-naphthylamine were analyzed using an excess of ceric sulfate (153), with a maximum error of 2%. T h e excess ceric sulfate was determined by back-titration with ferrous sulfate. Total itmino value and partial amino value have been defined and applied to the analysis of amine mixtures of high molecular weight ( 1 1 8 ) . T h e total amino value is the number of milligrams of hydrochloric acid required to neutralize 1 gram of amine sample, while the partial amino value is the number of milligrams required to neutralize secondary and tertiary amines in the sample. St,andard solutions of hydrochloric acid in alcohol are employed. Secondary amines can be separated from tertiary and primary amines by forming the nickel dithiocarbamates and extracting the primary and secondary derivatives from the mixture with a sodium hydroxide-ammonium hydroxide solution (99). T h e nickel in the secondary amine dithiocarbamate can be titrated with ethylenediaminetetraacetic acid (murexide indicator) after displacing the nickel n i t h silver ion in the case of small samples or decomposing the nickel dithiocarbamate with nitric acid in the case of larger samples. T h e rapid reaction of ethyleneiniine derivatives with excess sodium thiosulfate a t p H 4
CHp
-h-
/#
+ X a A 0 3 + €120
+
\'
--SHCH2-CH&03Ya
+SaOH
CN,
conwiies 1 mole of acid for each imino group present ( 2 ) and therefore may be used to estimate this type of compound. The acid consumed is measured by back-titration of the excess standard acid with standard alkali. T h e average deviation in the method is i.0.1%. Experiments show t h a t in the determination of methyl- and ethylimide groups, errors are introduced as a result of reaction of the alkyl iodlde produced with sodium thiosulfate used in the analysis ( 4 1 ) . T h e authors recommend t h a t a 10% solution of sodium antimonyl tartrate, a 5% alkaline solution of hydroxylamine hydrochloride, a 5% ascorbic acid solution, or a 5% hydrazine solution be used in place of sodium thiosulfate. Gravimetric procedures have been applied to the determination of individual compounds. Triethanolamine hydrochloride can be determined with an
accuracy within 2 to 7% using sodium tetraphenylboron as a precipitant a t a p H of 5 t o 6 (100). Application of the method t o mixtures of potassium chloride and triethanolamine hydrochloride gives results which are about 2% low in both components. Piperazine in dilute aqueous solutions is precipitated quantita10J1003.tively a-ith excess ammonium molybdate as 3CaHloX2. 8Hz0( 2 7 ) . T h e compound is dried a t 100" and weighed. Pyridine has been estimated with accuracy within 1 t o 3 7 , by adding copper nitrate and standard potassium thiocyanate to precipitate Cu( C5H5N)2(SCS)2and then determining the excethiocyanate (97). AMIKO ACIDS
After reviewing 55 papers dealing with the determination of serine and threonine, Schlormiiller and Kalter ( 1 2 7 ) conclutle that the two most important methods involve oxidation with lrad tetraacetate or with periodic mid. Both procedures give acrurate results, but the periodate procedure is to be preferred. T h e following procedure has heen suggested for the deteriiii1i:rtion of glycine, alanine, arginine, and cystine (151). Mix 5 to 25 ml. of a O.lyoaqueous solution of the amino acid with 2 ml. of a 30y0 sodium nitrite solution and 20 ml. of 3-\ sulfuric acid, and dilute to TO ml. ilfter heating for 15 minutes, add 50 ml. of 0.1N ceric sulfate solution, heat again for 15 minutes, cool, and titrate the excess ceric ion with 0 . 1 S ferrous sulfate. Urea interferes with the determination. An investigation of the action of periodic acid on amino acid3 and A'-methj-lamino acids ( 8 2 ) indicates that the method is not applicable to a quantitative determination of these compounds. EN0LS
T h e use of methanolic iodine monochloride in the Kurt i\Ze!.er enol titration results in increased accuracy and rapidity ( 4 8 , 4 9 ) . Solid sodium bicarbonate, nhich is insoluble in the methanol solvent, is used to remove hydrochloric acid as it is formed, thus eliminating the possibility of producing enol by acid catalysis. Bokadia ( 1 9 ) has made a critical study of the iMeyer enol titration when applied to the determination of enol in 2-formyl ketones, 2-formyl bromoketones, and certain unsaturated ketones. Errors and corrections which arise in the determination of theGe compounds are discussed. ESTERS
Aminolysis of phenolic esters ivith ethylenediamine permits application of the Fritz and Keen ( 4 4 ) phenol procedure to the analysis of these substances (52). A determination of benzoyl groups (123) involves hydrolysis with 9N sulfuric acid or 5hr sodium hydroxide, and extraction of the benzoic acid produced wit'h chloroform, folloa-ed by titration with sodium methoxide to a thymol blue end point, Ethj-l ethylmalonate as a contaminant in ethyl diethylnialonate samples can be determined as follows (56) when prepent i n concentrations greater than 1%. Adjust 3 ml. of the sample, in a glass-stoppered test tube, to 20" C., add 10 ml. of anhydrous n-propyl alcoholic potassiuni hydroxide, shake vigorously, and allow to stand for several minutes. After closing the tube Fvith a cotton stopper, heat 2 minutes in a boiling water bath, cool to 15" C., mix with 5 ml. of absolute acetone containing 1% n-propyl alcohol, and filter. Wash the precipitate with the acetone-n-propyl alcohol mixture and dry a t 100" C. ETHERS
T h e source of error in the alkoxy1 determination is the subject of several papers. Simple sugars and related compounds such as cellulose derivatives yield volatile iodine-containing compounds (53),when suhjected to the conventional niethoxyl determination. The error is eliminated b y using the trimethylamine absorber technique.
ANALYTICAL CHEMISTRY
710
The use of sodium thiosulfate solutions to remove hydrogen of phenol to a solid product by the ceric sulfate solution, followed iodide from alkyl iodides leads to erratic results (41, 69) because by filtration, drying, and neighing. p-Sitro-p'-aminoazobenzene (155) has been recommended as of interaction between the alkyl iodide and thiosulfate. Suban indicator for the nonaqueous titration of phenol in an ethyleneatitute washing solutions are suggested. Methoxyl and ethoxyl groups may be determined simultadiamine solvent. The application of the Koppeschaar bromination procedure to neously by conversion to the iodides, followed by absorption in the analysis of various nitrophenols (66) and 2,4-dinitrophenolisopropanolic trimethylamine (64). The tetramethylammopicric acid mixtures leads to erroneous results because of the renium iodide precipitates quantitatively; ethyl iodide is recovered placement of nitro groups by bromine under the conditions of the from the filtrate. Compounds such as 1,2dihydro-1,2-dimethyl-3,6-pyridazine- procedure. dione (11) and 1,2-dihydro-l-phenyl-2-methyl-3,6-pyridazine- Other phenols and phenol derivatives ( 1 ) which have been dedione (111) undergo rearrangement to the 0-methyl derivatives termined successfully by this method are 0-cresol, 4-chloro-2methylphenol, and 2-methylphenoxyacetic acid. under the conditions of the Zeisel determination (57). MisI n a comparative study of the iodine method and the coupling leading and unreliable results may be expected when the Zeisel method for the determination of 2-naphthol in phenyl-2-naphdetermination is applied to compounds of this type. thylamine and N,N'di-2-naphthylphenylenediamine (77), the CH CH iodine method was found to be unsatisfactory, but the use of the / \ / \ p-nitrobenzenediazonium chloride procedure n as successful. CH C=O CH C=O Picrate ion may be determined gravimetrically (104) by precipitation with 4-octyloxyphenj lguanidinium chloride followed by drying a t 110'.
&Ha I1
I
C& I11
The use of fuming hydrogen iodide permits the determination
of the ethoxyl group in alkyl ethoxysilanes (20). The analysis of a-haloakyl ethers (130) and a,@-dichloroalkyl, and a,p,p-trichloroalkyl ethers (131) is based upon their hydrolysis to a hydrohalie acid, an aldehyde, and an alcohol. The acid may be titrated with base or the halogen determined argentometrically. OXIRANES
Dilute aqueous solutions of epoxides or glycol mixtures can be analyzed with an accuracy within =k 0.5% (149). The sodium hydroxide, liberated in the reaction of epoxide ring with sodium sulfite, is titrated with standard hydrochloric acid. Glycidic esters react quantitatively with hydrogen iodide to produce iodine. Titration of the iodine with sodium thiosulfate provides a convenient method for the determination of these compounds (56). PEROXIDES
Procedures for the determination of organic peroxide have been critically examined. A comparison of the Wheeler iodide and stannous chloride chemical methods n ith the polarographic method (115) indicates that they yield identical results with pure peroxides. The polarographic method is recommended for impure samples because of its greater selectivity. The arsenious oxide method of Siggia (133) was found, on the average, to give higher values (If!?) for peroxide than the Kokatnur-Jelling procedure (7'8). Rlodifications of the latter procedure when applied to the determination of benzoyl peroxide are presented. PHENOLS
Ceric sulfate has been employed in the determination of phenol and phenol derivatives in both volumetric and gravimetric procedures. Phenol is oxidized rapidly at room temperature by ceric sulfate (140, 15d), whereas hydroquinone, pyrocatechol, resorcinol (150), phloroglucinol, and pyrogallol (162) require elevated temperatures for complete reaction. The reaction with cresol is incomplete. The excess ceric sulfate is determined by backtitration with ferrous sulfate. An empirical gravimetric method (140)involves the oxidation
SULFEYI L HALIDES
Kharasch and Wald (7'8) report the adaptation of an iodometx ic method for the analysis of 2,4-dinitrobenzenesulfen~I halides. Iodine, which is formed according to the equation 2 ArSCl
+ 21-
4
ilrSSAr
+ + 2C112
is consumed by the addition of excess sodium thiosulfate, the excess being determined by back-titration with a standard iodine solution. An accuracy within f 1% is obtained if anhydrous media are employed. SULFIDES
When the bromometric method of Siggia and Edsberg (134)is extended to derivatives of mercaptoacetic acid (46), the results are usually high, owing to sulfone formation, or reaction with the methylene group, whereas with 2-thiophenecarboxylic acid and derivatives, the reaction is incomplete. The stoichiometric value of bromine should be determined for each compound. THIOLS
Mercapto derivatives containing the structure -S=C-SH
I
are oxidized quantitatively by selenious acid (40). After reaction of the selenious acid with nitrogen heterocyclic compound or with the thiosemicarbazone, the excess oxidizing agent, is determined iodometrically. Thioacetals and thiolic esters can be titrated quantitatively a t 30" to 40' in acid media with 0.1N bromide-bromate solution (46, 47) to a permanent yellow end point. UNSATURATION
The usual procedure for the determination of olefins involves the addition of halogen or some other reagent to the double bond. Rosin acids containing two double bonds react instantaneously with methanolic bromine solution (64). Dehydroabietic acid and tetrahydroabietic acid do not react under these conditions and dihydroabietic acid reacts only slowly. Unsaturated amines (158) give unreliable iodine numbers because of the replacement of amino hydrogen by halogen. Satisfactory values can be obtained if the amine is first converted to its hydrochloride in an alcoholic chloroform solvent. Arve ( 5 )reports that mercurous acetate accelerated the addition of iodine to the double bond in determinations of iodine number.
V O L U M E 28, NO. 4, A P R I L 1 9 5 6 Ethylenes and substituted ethylenes may be determined with an accuracy within 1 to 3% (31) by reaction with excess mercuric acetate. The excess is estimated by titration with propylene glycolic hydrochloric acid to a thymol blue end point. This method is superior to the Marquardt-Luce (89) alkimetric procedure when applied to the determination of vinyl acetate and allyl acetate. llodifications are reported in the usual procedure for the determination of acetylenic compounds by precipitation with silver nitrate followed by titration of the h j drogen ion produced. The use of saturated solutions of silver nitrate or silver perchlorate, to form a soluble complex with acetylene (IO),permits analysis of acetylenic alcohols, hydrocarbons, carboxylic acids, and amines with an accuracy within 0.5%. The principal advantage is the elimination of the precipitate which interferes n i t h the detection of the end point. Another modification (90) employs silver benzoate i n place of silver nitrate to form the insoluble silver acetylide, follon-ed by titration of the benzoic acid produced. Copper acetylide in the presence of other copper compounds is determined by decomposing the acetylide TT ith potassium cyanide (108). The acetylene produced is determined in the usual n ay.
RIISCELLANEOUS METHODS MIXTURES
Mixtures of methanethiol, dimethyl disulfide, and dimethyl sulfide are analyzed by first absorbing the thiol in mercuric cyanide and the sulfide and disulfide in benzene. The methanethiol, upon absorption in 4% mercuric cyanide, is converted to me, curie dithiomethoxide [Hg(SCH3)2]. This latter compound can be determined either by weighing, iodometrically, or by analyzing the mercuric cyanide solution for liberated cyanide ion. The dimethyl disulfide in benzene is reduced to methanethiol and determined by a Volhard titration. Dimethyl sulfide is oxidized with broinine water and the liberated hydrogen bromide is titrated. Results are within 5% of the theoretical values. The method can probably be applied to homologous compounds (129). Thiols have been determined in the presence of hydrogen eulfide by taking advantage of the difference in solubility of CdS and Cd(SR)z under conditions of controlled pH. From the iodornetric determination of sulfide after separation of the more soluble Cd(SR)2 and from the iodometric determination of total thiol (H1S and RSH) on a separate portion, both sulfide and disulfide can be calculated (30). Disulfide in the mixture can be determined by modification of the zinc-acetic acid reduction method of Bell and Agruss (16). A rather unusual method for determining acetic acid in acetic anhydride depends upon the reaction of triethylamine (in benzene) with the acid in the anhydride. The reaction appears to be as follows: 3HOAc (CzH6)aN + (CzH~)&.3HOAc
+
.4 methyl red indicator is used, and the end point is taken as that point a t which the titration sample has the same color as methyl red in benzene (87). The method is probably applicable to the determination of other acids in their anhydrides. -4procedure for sodium laurate in sodium lauroyl sarcosinate is based on the insolubility of lauric acid in diammonium phosphate. The lauric acid is then titrated with a cationic detergent using a difluorescein indicator (63). The bromate-bromide method for phenols has been applied to certain alkylated phenol mixtures by taking advantage of the different number of ortho and para positions available for bromination in alkylated and nonalkylated phenols (141). The effect of p H on the periodate oxidation of glucose and sucrose permits the analysis of mixtures of glucose, sucrose, and soluble starch. I n the presence of a bicarbonate-buffered solution at 25" only glucose is oxidized by excess periodate. After
711 removal of starch with cadmium hydroxide, the total of glucose and sucrose can be determined by periodate oxidation in acid solution. After the oxidations, the excess periodate is determined by titration with thiosulfate (113). An evaluation of several methods for the determination of total peroxide, total aldehyde, and formaldehyde in solutions containing hydrogen peroxide, acetaldehyde, and formaldehyde (122) indicates that total peroxide is best determined by thiosulfate titration of the iodine liberated from glacial acetic acidhydrogen iodide solution. Total aldehyde is determined by oxidation with hydrogen peroxide in the presence of a known amount of alkali. The acid formed from the aldehyde neutralizes part of the alkali. Titration of the excess base gives an indirect determination of the aldehyde. The study s h o m that formaldehyde is best determined colorimetrically with Schiff's reagent after removal of peroxides. A rapid method for determining the carbon dioxide content of ethanolamine solutions consists of adding excess sodium hydroxide to the solution and back-titrating with 0.5'Y acetic acid (162).
SUGARS AND RELATED SUBSTANCES Aldonic acids have been determined by titration with standard calcium chloride solution a t p H 12.4. The method is based on the sequestering action of sodium gluconate (and related substances) for calcium in strongly alkaline solution. S o indicator is used in the titration. The end point is a distinct and persistent turbidity. The methods appear to be applicable to quantitative differentiation between certain acids (69). The calcium content of calcium pectate has been determined by titration with (ethylenedinitri1o)tetraacetic acid (EDT-4). Pectate ions do not interfere. Calcium contents of precipitates containing 6 to 24 mg. of calcium (as calcium carbonate) were found to be propoitional to the quantities of citrus pectin from which the precipitates came (61). The method of Kline and Acree ( 7 6 ) (in which the aldehyde group is oxidized by hypoiodite) is reported to be subject to serious error when applied to mannose. The following modification has been suggested to overcome this difficulty (29). To 0.225 gram of the hexose is added equal volumes of 1N sodium carbonate and 0.1N iodine (containing 60 grams of potassium iodide per liter). The mixture is kept a t 20" for 30 minutes after the first addition of iodine solution and is then acidified with 6 S hydrochloric acid and the excess is titrated with 0.1.V thiosulfate solution, using a starch indicator. The determination of mannose and mannans as mannose phenylhydrazone (116) has been modified so that the method requires less time (117). I n studies on the hydrolysis of dextran and the destruction of glucose ( 3 4 )it has been found that essentially the same maximum yield of reducing sugars and concurrent loss of glucose are obtained whether the hydrolysis is carried out with 2 or 4N sulfuric acid a t 100" or 1N sulfuric acid a t 120'. The time necessary to reach the maximum yield varied, honever, from 50 to 180 minutes. I n comparing sulfuric acid and hydrochloric acid it n as noted that the acids were equivalent on a molarity basis rather than on a normality basis with respect to time of hydrolysis and rate of destruction of glucose. A standardized procedure for analytical hydrolysis of different types of dextrans is given. I t uses a 0.5% solution of dextran in 4 S sulfuric acid heated a t 100' for 75 minutes. The reducing poner of the hydrolyzate is corrected for an approximately 4% loss of glucose during the hydrolysis. The following reaction
0 R6-H
+ 3HC102
+
RCOZH
+ 2C102 + HC1 + HzO
takes place in phosphate buffer solutions a t p H 2.4 to 3.4 a t 50". By using a known excess of chlorous acid and determining the
ANALYTICAL CHEMISTRY
712 unused chlorous acid iodometrically, the reaction becomes the basis for a quantitative determination of glucose. The chlorous acid reagent decomposes during the reaction and a n estimated correction must be made for this. The favorable stoichiometry makes the method useful for determining trace amounts of glucose. The method can presumably be applied to other aldoses (81I . Another method for determining reducing sugars (110) is based on the complexometric titration of cuprous oxide in alkaline solution. A solution containing complexon I11 [sodium salt of (ethylenedinitri1o)tetraacetic acid] as the complex-forming reagent is suggested. For the determination of small changes in sugar concentration, t\vo new procedures make use of the oxidizing properties of ceric perchlorate (39). I n one of the methods the excess ceric perchlorate is decomposed ivith sodium oxalate, while the second method uses arsenite solution in the presence of osmic acid. The availability and properties of sodium borohydride will probably lead to its quantitative application in a number of instances. One way in which this reagent has been applied is a gasometric method for reducing sugars (and other carbonyl compounds) (137). I n this method a n aqueous solution of sodium borohydride is standardized by measuring the volume of hydrogen evolved upon acidification of the solution. The sugar sample is treated with the borohydride solution and then, after the reduction is completed, the excess borohydride is determined by acidification and measurement of the hydrogen evolved. Reduction is coniplete in 20 to 30 minutes a t room temperature or in less than 1 minute a t the boiling point. An accuracy within 1yo of the correct value has been obtained in the determination of glucose, fructose, galactose, lactose, and glucosamine. The method appears to be similar to that of Lindberg and Misiorny
(81). -4method for fructose (111) depends upon oxidation with a known volume of alkaline copper solution. After the oxidation the solution is neutralized, treated with potassium iodide solution and starch indicator, and then titrated with standard t'hiosulfate solution to determine the excess cupric ion in the solution. For the determination of starch in concentrations up to 250 p,p,m. a rather empirical dichromate oxidation method appears to be convenient. The oxidation is preferably conducted in an autoclave a t 120' for 30 to 60 minutes (128). T h e unconsumed dichromate is determined either by addition of excess Mohr's salt and tit,ration of the excess ferrous ion with permanganate or colorimetrically. The starch is reportedly oxidized to carbon dioxide, water, and stable compounds of low molecular weight. The method has also been applied to laurylamine acetate and to sodium oleate. It might be useful for routine determination of various other organic substances. I n the periodate method for determination of end-group values of polysaccharides it is necessary to use carefully standardized conditions (96). il modified procedure has been described in n-hich the oxidation period is 30 hours. The formic acid determined in the titration is corrected for a n average yield of 81% as determined ivit,h sucrose. hscorbic acid may be titrated directly with a solution of !Yhromosuccinimide in the presence of starch and iodide as indicator. One advantage of the method depends upon the fact that Ar-bromosuccinimide selectively oxidizes ascorbic acid before other reducing substances. The other commonly used method for ascorbic acid uses 2,6-dichlorophenolindophenol and is limited by the presence of other reducing substances (g). WATER
Improvement in the stability of Karl Fischer reagent is obtained by using methyl Cellosolve instead of methanol in preparing the reagent. This modification of the reagent also extends the applicability of the method by permitting a wider choice of sample solvent. I n the determination of water in
aldehjdes and ketones, a solvent consisting of ethylene glycol and pyridine is advantageous. It eliminates the possibility of the reaction of methanol x i t h carbonyl group to give an acetal and a a t e r (107). A new reagent for the determination of water consists of a solution of sulfur dioxide and bromine in chloroform. I t is used much like the ordinary I k r l Fischer reagent, but is reported to be more stable and give results which are more nearlj stoichionietric. The disappearance of the bromine color serves as a satisfactory end point. The main disadvantage of the new reagent appears to be that alcohols interfere in the water determination ( 1 4 j . UNCLASSIFIED
hlost of the methods which have been used for the determination of quaternary ammonium compounds are based on huerbach's reaction (6),n-hereby certain acidic dyes react' with quaternary ammonium compounds to give a product that is insoluble in irater but soluble in certain organic solvents. Recent studies (8)of the shift in the absorption spectrum of bromophenol blue when cetyltrimethylammonium bromide is added indicate that the reaction probably involves complex formation. Ascorbic acid reduces indophenols slowly, but air oxidizes them again. The following technique permits the titration of indophenol samples with a standard solution of ascorbic acid.
Most of the ascorbic acid is added rapidly to the sample, and the solution is allowed to stand for 10 to 15 minutes with periodic shaking. The titration is then finished in 1 to 2 minutes with energetic shaking of the sample. ( A preliminary titration is necessary to establish h o v much ascorbic acid to add in the first addition.) An inert gas atmosphere is not required. Ascorbic acid solutions are prepared by dissolving a weighed amount in 2'3 sulfuric acid prepared from boiled water. The solution is standardized with potassium iodate, or standardization may be omitted if sufficiently pure ascorbic acid is used. The solution keeps for onlj- 1 to 2 days ( 1 4 5 ) . The reaction of 1-naphthglthioiirea ivith bromine to give 2,4dibromo-1-naphthylurea is the basis for a n e x determination of the former compound (167). The sample is dissolved in 100 nil. of acetic acid and 5 nil. of 2.5% hydrochloric acid and then titrated with O,llV pot iinn hypobromite. I n broniinating the ring a n d reacting n-ith the thiocarbonyl group a total of 12 equivalents of bromine are used per mole of sample. 2-Saphthylthiourea cannot be determined by this method because the analogous reaction in this caPe is too sloii-. -1nen. method for the estimation of xanthates appears to be dependent iipon the favorable solubilitj- of lead xanthates in benzene. The sample is treated n-ith lead nitrate solution. T h e lead xanthate is taken up in benzene and washed with water to remove excess lead salts. T h e benzene layer is evaporated to dryness and the residue of lead xanthate is weighed. The weight of the residue is multiplied by the empirical factor 0.i12 to find the n.eight of potassium santhate in the sample (88). The potassium xanthates of 12 comnion alcohols can be titrated potentiometrically or in the presence of a n indicator in glacial acetic acid, even though the xanthates are unstable in this solvent (17). The explanation for this apparent anomaly lies in the fact that the ROCSS- ion either neutralizes a solvated proton or acquires the hydrogen from a neutral acetic acid molecule. The ROCSSH thus produced decomposes, and the acetate ion neutralizes a free solvated proton, thus keeping the reaction stoichiometric. Ion exchange resins continue to find many applications in analytical chemistry. The follou-ing procedure is used in determining both sulfur and barium in barium sulfonates ( 2 4 ) . The barium salt, dissolved in water, is passed through a small cation exchange column. The free sulfonic acid is eluted and oxidized to sulfate by one of the customary methods. The column is then eluted from the other end with 12% hydrochloric acid, and the barium in the eluate is precipitated with sulfuric acid. The number of -CH&H20groups in ethylene oxide con-
V O L U M E 28, N O . 4, A P R I L 1 9 5 6 deneation products can be deterniiiied by treatment of the condensation product with a known eycess of potassium ferrocyanide, the precipitate which forms is removed by filtration and the excess ferrocyanide in the filtrate is titrated with zinc sulfate ( 1 2 4 ) . Approximately 0.7, 1.0, and 1.5 moles of potassium ferrocyanide react n ith the condensation products of nonylphenol n Ith 6, 9, and 12 moles of ethylene oxide. Tetramethylphosphonium chloride can be determined in aque011s solution by the addition of an excess of chloroplatinic acid. _\iter evaporation to dryness, the residue is washed u i t h alcohol, filtered, !\\shed, dried, and neighed. The accuracy is nithin 0 5%. Atoderate amounts of calcium, magnesium, and strontium ions do not interfere, but ammonium, potassium, rubidium, and cesium ions are also precipitated. Alternatively, the tetramethylphosphonium cation can be removed with a cation exchange resin, and the hldrochloric acid can be titrated ( 3 ) . Hexahydro-1,3,5-trinitro-s-triazine (RDX) is apparently titratable as a tribasic acid if the sample is dissolved in dimethylforniamide and titrated with sodium methoxide in a benzenemethanol solvent (71 ), Titanous chloride has been used for the reduction of the nitro group of nitroguanidine and conditions have been worked out to make this method essentially quantitative (23, 146). Other investigators (143) have determined the uitrogeii in uitioguanidine and i n nitiocellulose by using the sample as the nitrating agent for the transnitration of salicylic acid. The 5nitrosalicylic acid thus formed is estimated by reduction n-ith an excess of standard titanous chloride. LITERATURE C I T E D
Aichenegg, P., Haynes, H. G., J . A p p l . Cheni. ( L o n d o n ) 4, 137-40 (1954). Allen, E., Seaman, W., AXIL. CHEM.27, 540-3 (1955). Anderson, C. J.. Keeler, R. A , , Ibid., 26, 213-14 (1954). Arikawa, Y..Kato, T., Technol. Repts. Tohoku Cnio. 19, 104-10 (1954). .Irve, W., Angew. Chem. 64, 311-12 (1952). Auerbach, 31. E . , IND.EKG.CHEM.,Ax.4~.ED. 15, 492 (1943). Bacila, &I., Ferencz. G., Arquiv. biol. e tecnol., Inst. b i d . e pesquisas tecnol. 4, 25-9 (1949). Badinand, A , , Guiraud, J., Trac. soc. pharm. Montpellier 14, No. 3. 119 (19541. Barakat, AI. Z., Add El Wahab, 31. F., El-Sadr, 31. 31., .&N.~L. CHEM.27, 536-40 (1955). Barnes, L., Jr., hlolinini, L. J., Ibid., 27, 1025-7 (1955). Uel’nikov, S . S . ,Zhur. Anal. A-him. 8, 119-21 Baskakov, 1., (1953). Bates, R. W.,Etheredge, AI. P., Quackenbush, F. IT., Jr., J . Assoc. o f i c . Agr. Chemists 38, 56-61 (1955). Belcher, R., Chim. anal. 36, 65-7 (1954). Belcher, R., !Vest, T . S.,J . Chem. SOC.1953, 1772-6. Bell, R. T . , Agruss, AI. S., TND. EKG.CHE (1941). Berger, A, Sela, 11., Katchalski, E.. ANAL.CHEM.25, 1554-5 (1953). Berger, J . , Acta Chem. Scand. 6, 1564 (1952). Bogdanov, K. -I.,Ilasloboino-Zhiroraya Prom. 18, S o . 8, 18-19 (1953). Bokadia, h l . AI., Agra rniv. J . Research 2, Pt. 1, 9-16 (1953). Bournique, R. d.,Chemist Analyst 43, 40-1 (1954). Bradstreet, It. B., -&BAL. CHEM.26, 185-7 (1954). Ibid., pp. 235-6. Brandt, W. W., DeVries, J. E., Gantz, E. St. C.. Ibid.. 27, 393 (1955). Brauns, F. E., Hlsva, J. B., Seiler, H., I b i d . , 26, 607 (1954). Castiglioni, A , , Atti accad. sci. Tornio, Classe sci. jis. mat. e nat. 87, 18-20 (1952-3). Castiglioni, -4., Bionda, G., 2. anal. Chem. 141, 38-9 (1954). Castiglioni, A , , Vietti, &I., Ibid., 142, 18 (1954). Clark, J. R., Wang, S. AI^, ABAL.CHEM.26, 1230 (1954). Collins, J. R., A n a l . Chim. Acta 9, 500 (1953). Coope, J. 4.R., Maingot, G. J., ASAL.CHEM.27, 1478 (1955). D ~ sA, l . N., Ibid., 26, 1086-7 (1954). Das, AI. N., Palit, S. R., J . I n d i a n Chem. Soc. 31, 34-8 (1954). Datta, J., Ibid., 31, 153-6 (1954). Dimler, R. J., Davis, H. A , , Gill, G. J., Rist, C. E., ASAL. CHEM.26, 1142 (1954). Dullaghan, 31. E.. Nord. F. F., Mikroehim. Acta 1953, 17-21.
713 (36) Dupuy, P.. Iuortz, AI., Compt. rend. 238, 587-8 (1954). (37) Erskine, J. R. B., Strouts, C. R. S . , Walley, G., Lazarus, IT., dnalyst 78, 630-6 (1953). (38) Fedoseev, P. K., Logoshnaya, R. AI., Zhur. Anal. K h i m . 9, 37-
41 (1954). CHmf. 27, 1166 (1955). (39) Forist, A. A , , Speck, J. C., Jr., ;IXAL. (40) Franchi, G., Ann. chim. (Rome) 42, 701-6 (1952). (41) Franaen, F., Disse, W.,Eysell, K., Mikrochim. Acta 1953, 44-50. (42) Freeman, S. K., ANAL.CHEW25, 1750-1 (1953). (43) Frisone, G. J., Ibid., 26, 924-5 (1954). (44) Fritz, J. S., Keen, R. T . , Ibid., 25, 179-81 (1953). (45) Gauthier, B., Maillard, J., Ann. pharm. franc. 11, 509-23 (1953). (46) Gauthier, B., Maillard, J., Compt. rend. 236, 1778-80 (1953). (47) Ibid., pp. 1890-2. (48) Gero, il., ANAL.CHEM.26, 609 (1954). . 19, 469-71 (1954). (49) Gero, rl., J . O ~ QChem. (50) Gertner, A., Ivekovic, H., 2. anal. Chem. 142, 36-40 (1954). (51) Glagoleva-lIalikova, E. M . , Latvijas PSR Zinatnu .4kud. Vestis 1949, No. 6 (Whole No. 23), 121-3. (52) Glenn, R. A , , Peake, J. T., ASAL. CHEM.27, 205-9 (1955). (53) Gran, G., Stensk Papperstidn. 56, 179-80 (1953). (54) Ibid., 57, 702-8 (1954). (55) Green, N., Schechter, 11. S.,ANAL.CHEM.27, 1261-5 (1955). (56) Gyenes, I., JJagyar KBm. Folydirat 58, 299-302 (1952). (57) Gysel, H., Mikrochim. Acta 1954, 743-5. (58) Hartman, L., J . A p p l . Chem. (London) 3, 308-11 (1953). (59) Heron, A. E., Reed, R. H., Stagg, H. E., Watson, H., A72alyst 79, 671-80 (1954). (60) Hogsett, J. X . , Kacy, H. W., Johnson, J. B., ANAL.CHEM.25, 1207 (1953). (61) Holt, R., Analyst 79, 623 (1954). (62) Holaapfel. L.. Gottschalk, G., 2. anal. Chem. 142, 115-19 (1954). (63) Iwasenko, H., J . dssoc. Ofic. Agr. Chemists 37, 534 (1954). (64) Jalava, P. 0.. P a p e r i i a Puu 36, 69-70 (1954). (65) Johnson, J. B., Funk, G. L.. ANAL.CHEM.27, 1464-5 (1955). (66) Johnson, L. D., LIcNabb. IT. AI., Wagner, E. C., Ibid., 27, 1494-8 (1955). (67) Johnston, V. D., M j g . Chemist 25, 337-8 (1954). (68) Jong, J. I. de, Rec. trau. chim. 72, 653-4 (1953). (69) Karabinos, J. W., Ballum, A. T., LIcBeth, R. L., As.4~.C H E x 25, 1563 (1953). (70) Kato, T., Arikawa, Y., Technol. Repts. Tohoku Cniv. 17, 163-9 (1953). (71) Kay, s. nf.,ANAL. CHEM., 27, 292-4 (1955). (72) Kennett, B. H., J . AQT.Food Chem. 2, 691-2 (1954). (73) Kharasch, N., Wald, M .AI., ANAL.CHEM.27, 996-8 (1955). (74) Kiba, T., Terada, K., J . Chem. SOC.Japan, Pure Chem. Sect. 75, 196-8 (1954). (75) Kitamura, R., J . Pharm. SOC.Japan 57, 209-12 (1937). (76) Kline, G. lI.,.4cree, 9. F.. ISD. EX. CHEM.,:\BAL. ED.2, 413 (1930). (77) Koide, T., Kubota, T., Ruroi, T . . J . Soc. Rubber I n d . J a p a n 25, 6-8 (1952). (78) Kokatnur, 5’. R . , Jelling, 31., J . -4m. Chem. Soc. 63, 1432-3 (1941). (79) Korbl, J., Chem. Listu 49, 858-68 (1955). (80) Kurchatov, 31. S., Bull. inst. chim. acad. bulgare sci. 2, 191-247 (1953). (81) Launer, H. F., Tomimato, Y., ANAL.CHEM.26, 282-6 (1954). (82) Lee, V., Ling, K., J . Formosan M e d . Assoc. 53, 67-71 (1954). SAL. CHEM.26, 748-50 (1954). (54) Lindberg, B., hIisiorny, A , , Srensk Papperstidn. 55, 13 (1952). (85) Lucas, J. F. C., Anales real soc. espafi. fis. y qulm. (Madrid) 50B, 535-8 (1954). (86) Lucas, J. F. C . . R e t . cienc. a p l . (Madrid)8, 103-11 (1954). (87) lIcClure, J. H., Roder, T. AI., Kinsey, R. H., -4s.4~.CHEM.27, I599 (1955). ( 8 5 ) llajumdar, K. K., J . Sci. I n d . Research ( I n d i a ) 11B, 260 (1952). ~ ~ ~20,. 751 (1948). (89) llarquardt, R. P., Luce, E. S . ,A 4 CHEM. (90) Marssak, I., and Koulkes, I I . , M e m . serzices chim. &at. (Paris) 36, NO.4, 421-6 (1951). (91) LIetcalfe, L. D., Schmitz, -4. b.,ANAL.CHEM.27, 138 (1955). (92) lleyer, R., 2. anal. Chem. 140, 184-5 (1953). (93) AIikl, O., Pech, J., Chenz. L i s t y 47, 904-6 (1953). . 26, 1222-3 (1954). (94) IIilner, 0. I., Shipman, G. F.. A N ~ LCHEX (95) lIodiano, J., Pariaud, J. C., Bull. SOC. chim. France 1954, 18991. (96) llorrison, AI., Kuyper, A . C., Orten, J. M., J . Am. Chem. SOC. 75, 1502-4 (1953). (97) JIusha. S..hIunemori. MI.. J . Chem. Soc. Javan. I n d . Chem. Sect. 58, 393 (1955). (98) Sagasawa, K., Ohkuma, S., J . Pharm. SOC.J a p a n 74, 410-13
ANALYTICAL CHEMISTRY Kebbia, L., Guerrieri, F., Chimica e industria ( M i l a n ) 35, 896-9 (1953). Neu, R., 2. anal. Chem. 143, 254-7 (1954). ANAL.CHEY.26, 600 (1954). Oita, I. J., Conway. H. S., Oliver, F. H., Analyst 80, 593 (1956). 27, 1177-8 Owens, 11. L., Jr., hIaute, R. L., ANAL. CHE~I. (1965). Pasini, C., Vercellone, A , Z . anal. Chem. 143, 172-7 (1954). Perlin, A. S., ANAL.CHEX 26, 1053-4 (1954). Pesez, &I., Bull. soc. chim. France 1954, 1237-8. Peters, E. D., Jungnickel, J. L., ANALCHEW27, 450-3 (1955). Zhur. Anal. K h i m 8, 302-5 (1953). Polyakov, K.K., , 64, 1913 (1931). Ponndorf, W ~ Ber. Potterat, 31., Eschmann, H., M z t t . Lebensm. Hyg. 45, 312 (1954). Prillinger, F., Mitt. Hoheren Bundeslehr- 7 1 . T’ersuchsanstaZt Wezn- u. Obstbau Klosterneuburo, Hoheren Bundeslehr- u. T’ersuchanstalt Bienenkunde Wien Grinzino 2. -, 20 (1962). Radford, A. J., Analyst 79,501-4 (1954) Reifer, I , Tarnowska, K , Przemysl Chem 31 ( 8 ) , 58 (1952). Reznikov, I. G., Farber, E. L., Maslobotn- Zhiroraya Prom. 18, SO. 5, 13-16 (1953). Ricciuti, C., Coleman, J. E., Willits, C. O., ANAL. CHEM.27, 406-7 (1955). Roudier, ~ A . Eberhard, , L., Mens. serbices chini. &at. (Paris) 36, 383 (1951). Ibid., 37, 227 (1952). Sakakibara, S.,Komori, S . , J . Chem. SOC.J a p a n , I n d . Chem. Sect. 56, 429-30 (1953). Salomaa, P., S o r d . Kemistmotet Helsingfors 7, 201-2 (1950). Salomaa, P., Suomes Kemiastilehti 27B, No. 2, 12-14 (1951). Sant. B. R.. 2. anal. Chem. 145. 267-60 (1955). Satterfield, C. N., iT7ilson, R. E., Le Clair, R.’lI., Reid, R. C., ASAL. CHEM.26, 1792 (1954). Schivizhoffen, E. Y., Dana, H., 2. anal. Chem. 1 4 0 , 8 1 4 (1953). Schonfeldt, N.. h’ature 172,820 (1953). Schoniger, W., dfikrochim. Acta 1955, 123-9. Schomberg, XI., Compt. rend. acad. agr. France 40, 271-3 (19543. Schormuller, J , Walter, J., 2 . anal Chem. 134, 337-53 (1952) Schulz, 6. F., ANAL.CHEX 25, 1762-3 (1953) Segal, W., Starkey. R. L., Ibid., 25, 1645 (1953). Shostakovskil, AI. F., Bogdanova, A. Y., Zhur. A n a l . Khim. 8, 231-4 (1953). Shostakovskii, 11. F., Sidel’kovskaya, F. P., Ibid., 9, 105-S (1954). Siegel, H., U‘eiss, F. T.. ~ X A L CHEM. . 26, 917-19 (19641. Siggia, S.,Ibid., 19, 972-3 (1947). Siggia, S.,Edsberg, R . L., Ibid., 20, 938-9 (1948). Siggia. S., Stahl. C. R., Ibid., 27, 550-2 (1955). Sjostrom, E., Acta Chem. Scand. 7, 1392-4 (1953). Skell, P. S.,Crist. J. G., .Vatwe 173, 401 (19*54).
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REVIEW OF FUNDAMENTAL DEVELOPMENTS IN ANALYSIS
~I
I 1
I Biochemical Analysis
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I
B
(138) Smirnov, 0 . K., Beahentseva, V. M., Zavodskaya Lab. 21, 414 (1955). (139) Spencer, D., Henshall, T., Anal. Chim. Acta 11, 428-30 (1954:. (140) Spencer, W. R., Duke, F. R., ANAL.CHEM.26, 919-20 (1954). (141) Spliethoff, W. L., Hart, H., Ibid., 27, 1492 (1955). (142) Stakheeva-Kaverzneva, E. D., Salova, A. S., Zhur. A n a i . K h i m . 8, 365-9 (1953). (143) Stalcup, H., Williams, R. W,, A N ~ LCHEX . 27, 543 (1955). (144) Staudinger, H., Siessen. G., Chem. Ber. 86, 1223-6 (1953). (146) Stepanov, B. I., Sergienko, V. A., Trudy Komissii Anal. Khim., Akad. Nauk S.S.S.R. Otdel. K h i m . Nauk 5 (8), 274 (1954). (146) Sternglanz, P. D., Thompson, R. C., Savell, W. L., AN\TAL. CHEAI.25, 1111 (1953). (147) Suda. K., Yamamoto, S., Kusagawa, T., Research Repts. Fac. Textiles and Sericult., Shinshu Univ. 1, 63-6 (1951). (148) Svirbely, W. J., Roth, J. F., ANAL.CHEX 26, 1377-8 (1964). (149) Swan. J. D.. Ibid.. 26. 878-80 (1954). i15Oj Takahashi. T.. Kirno;o. K.. Kimoto. 11..J. Chem. SOC. Ja~an. Ind. Chem. Sect. 55, 283-5 (1952) (151) Takahashi, T., Kimoto, K., hlinami, S., Ibid., 55, 805-6 (1952). (152) Ibid., 56, 491-3 (1953). (153) Takahashi, T., Kimoto, K., Takano, Y., Ibid., 56, 571-3 (1953). (154) Takeda: K.,Senda, J., .Yogaki K e n k y u (Rept. Ohara Inst A g , . B i d ) 41, 97-118 (1964). (155) Takiura, K., Takino, Y , J . Pharm. SOC.Jupale 74, 971-4 (1954). (156) Tanaka, Y., Ibid., 75, 653-5 (1955). (157) Terent’ev, A. P., Zabrodina, K. S., Doblady Akad. S a u k S . S. S. R. 95, 85-7 (1954). (158) Tomicek, O., Krepelka, S., Chem. Listy 47, 526-30 (1953). (159) Tomicek, O., Vidner, P Ibid., 47, 521-5 (1953). (160) YanEtten, C. H., Wiele, 11. B., ANAL.CHEY 25, 1109-11 (1953). (161) \-iallard, R., Corval, 11.. Dreyfus-Alain, B., Grenon, 11.. Hermann, J., Chim. anal. 36, 102-4 (1954). (162) Wagner, P T., Lew, AI., .\SAL. CHEM.26, 575 (1954). (1631 Katanabe. H.. J . Chem. SOC.J a v a n . Pure Chem. Sect. 76. 1-3 (1955). (164) White, T. T., Penther, C. J., Tait, P. C., Brooks, F. R., . I N ~ L . CHEM.25, 1664 (1953). (165) Wickbold, R., Angew. Chem. 66, 1 7 3 4 (1954). (166) Wilson, H N.,Peterson. R. h l . , Fitagerald, D. lI.,J . A p p l . Chem. (London) 4, 488-96 (1954). (167) Wojahn, H., Arch. Pharm. 286, 278 (1953). (168) Kojahn, H., Wempe. E., Ibid.. 285, 375-82 (1952). (169) Tamagishi, AI., Tokoo, 11.. Inoue, S., J . Pharm. SOC.J a p a n 75, 351-3 (1955). (170) Tudasina. A. G., Yysochina, L. D., IYauch. Zapiski Dnepropetrocsk Gosudarst I-niv. 43, 53-6 (1953) ; Referat. Zhur. K h i m . 1954, S o . 15.061.
EDWARD L. DUGGAN D e p a r t m e n t o f Physiological Chemistry, University o f California M e d i c a l School, University of California, Berkeley, Calif.
EFORE proceeding to the review of major developments in
biochemical analysis for the past 2 years, i t is well to state the general requirements and restrictions of biochemical analysis, in contrast t o those of analytical chemistry “Biochemical analysis is inherently a more complex and broad field than classical chemical analysis. Because the major activitj- of the biochemist is always to find out what and how much, biochemical analysis actually miist include virtually every biochemical technique” (7’3). Because the biochemist directs his analysis toward the understanding of structure and content of biological units, his analJ ses
must be accomplished on ssniples JThich vary enormously in interfering substances, such as proteins, nucleic acids, and lipide. Rarely can an analysis be transposed without modification from analytical chemistry into biochemistry; this is apparent even in the case of the relatively simple technique of flame photometry. The biochemist manifests proper concern with fractionation and sample preparation before analyses are attempted, as the analyses have meaning only in their biological contest. Thus, developments in fractionation procedures are eagerly accepted, whether the fractionation is that of simple molecules, m a c omolecules, or cellular particulates.
