ANALYTICAL CHEMISTRY
632
Vizern, J., and Guillot, L., Compt. rend., 236, 813 (1953). Vogel, E., and Neukam, H., Milchwissenschaft, 8 , 284 (1953). Voronin, P. F., Gigiena i Sanit., 1953, KO.10, 51. Whistler, R. L., Hough, L., and Hylin, J. W..ASAL. CHEU., 25, 1215 (1953). White, J. W., Jr., and Maher, J., J . Assoc. Ofic. B g r . Chemzsts, 37. 466 (1954). (303) Wild;&, H. W:, Anderson, E. 0 , and Walls, D. E., J . Dairu Sci., 36, 87 (1953). (304) T’iilkie, J. B., and Jones, S. TI-., J . Assoc. O f i c . a g r . Chemists, 37, 880 (1954). (305) Wnkler, TI-. O., Ibid.. 36, 119 (1953).
Fertilizers
(306) Wolford, E. R., U. S. Dept. Agr., Bur. Agr. Ind. Chem., Mimeo. Circ. AIC-365 (1953) (307) T’iood, E. C., A n a l ~ s t78, , 451 (1953). (308) Woolf, L. I., Nature, 171, 841 (1953) (309) Worh, IT. J., ANAL.CHEXI.,26, 203 (1954). (310) Yemm, E. IT,,and Wdlis, -4.J., Biochem. J., 57, 508 (1954). (311) Young, H. Y.. and Gartner, ’CTT. A , , ANAL. CHmf., 25, 800 (1953). (312) Zaikomskii, Y. A., Korobova, N., and Ryabushko, L., Malolochanaya Prom , 14 ( 2 ) , 29 (1953). (313) Zeilinger, 9.,Intern. Dairy Congr., Proc. 13th Congr. (Hague), 2, 293 (1953).
I
G. L. BRIDGER Department
o f Chemical and
M i n i n g Engineering, Iowa State College, Ames, Iowa
T
H I S review covers the literature on analysis of fertilizers since the review published in the January 1953 issue of AXALYTICAL CHEMI~TRY and up to August 15, 1954 (15). I t has been restricted to procedures that are recommended for fertilizer analysis or that appear to be adaptable for fertilizer analysis with little modification. SAXIPLING AND SAMPLE PREPARATION
Randle (114, 115) presented an extensive table of analyses of 29 grades of fertilizer by 10 collaborators who used a handquartering procedure and of 22 samples by seven collaborators who used a riffle-quartering procedure. He also tabulated the results of analysis of fertilizers of 47 grades by 13 collaborators prepared by the official .40AC sample procedure. Fudge ( 4 1 ) reviewed current practices in collecting, storing, and sampling of nitrogen solutions and liquid fertilizers containing free ammonia.
graphic method for nitrates and nitrites, in which uranium salts were found superior to lanthanum salts. The analysis of gas mixtures containing oxides of nitrogen was studied by Johnson (69). l-uen and Pollard (150) described preparation of the Kessler reagent for determining nitrogen in agricultural materials. Alorgan and Kralovec (89) determined available fertilizer nitrogen in urea-formaldehyde compositions based on the nitrogen insoluble in cold water and that insoluble in a hot buffered phosphate solution. Rangier and Krebs (116) determined ammonia in the presence of large amounts of urea by a cold precipitation as the iodo-mercury complex. Rudorff and Zannier (121) described a titrimetric determination of potassium and ammonium in the presence of one another. Nagai and Kanazava (9s’) determined nitrogen in a mixture of calcium cyanamide and fused phosphate fertilizer. Kondo (76) analyzed reagent grade ammonium sulfate by four different procedures.
NITROGEN
Reports on determination of nitrogen in fertilizers by numerous collaborators by -4OAC methods, the Shuey method, and various modifications of the Kjeldahl method were made by Davis (26, 27). Nakamura and Yamazoe (96) compared various methods for determining nitrate nitrogen in fertilizers; they concluded t h a t the reduced iron method xvith steam distillation n-as best. Numerous studies Tvere made of the Kjeldahl method. MeKenzie and Wallace ( 8 1 ) made a critical study of temperature, catalyst, and oxidizing agent in the digestion step. Lepper (79) studied nitrogen loss when a selenium mixture was used in the digestion step; he concluded that nitrogen loss is not serious and there is little danger of selenium poisoning. Rosicky (119) found that addition of kerosine, fuel oil, or mineral oil to the digestion flask v a s helpful in prevention of foaming. Dickinson (28) applied the Kjeldahl method to determination of nitrogen in nitrates. Perrin (104) developed a rapid modification of the Kjeldahl procedure which compared favorably to other procedures. Hartmann and Bathge (59) used dicyclohexylthallic ion as a precipitating agent for the gravimetric and volumetric determination of nitrates. Feigl and Schaeffer (34) treated alkali nitrates with concentrated formic acid and titrated the resulting carhonate; the procedure was also applicable for alkali nitrates. Komarmy, Broach, and Testerman ( 7 5 ) developed a photometric procedure for high nitrate-containing solids in tvhich phenoldisulfonic acid was used. Masek (84)described a polnro-
PHOSPHORUS
Determination of available phosphoric acid in calcium metaphosphate %-asstudied by Jacob, Caro, and Magness ( 6 6 ) , who concluded that grinding of the sample to -60 or -80 mesh was necessary, depending on whether continuous or intermittent agitation was to be used during the citrate digestion. Jacob, Hoffman, and Schranim (67, 68) compared the direct determination of available phosphoric acid in a number of fertilizers by volumetric and photometric procedures. Allen (1) described a direct determination of available phosphoric acid in fertilizers for screening purposes. The gravimetric procedure for phosphate received the attention of several lvorkers. Pribil and Jelinkova (109) precipitated phosphate as magnesium ammonium phosphate. Shibata and Tsukiyama (128) found 0.02’% nitric acid better than 1% potassium nitrate with or Tvithout a small amount of nitric acid for wishing ammonium phosphomolybdate precipitate. Cole and Kilson ( 2 3 )used zirconium nitrate as a precipitant for phosphate. Hardin (58) described the use of a perchloric-nitric acid digestion. Several volumetric methods were described. Rancke-bladsen and Iijaergard (113) neutralized the phosphate solution to the H2POa- end point, then added cerium nitrate to liberate the remaining hydrogen ions, which xvere titrated with sodium hydroxide. Kindt, Balis, and Liehhafsky ( 7 3 ) titrated a phosphate solution with alkali after separation of calcium by ion exchange. Goudie and Rieman ( 5 5 ) found that an error was
V O L U M E 27, NO, 4, A P R I L 1 9 5 5 introduced in ion exchange procedures by the presence of carbonate and incomplete removal of ferric ion. Brouty and Chatelet (17) studied titration of phosphoric acid with lime and described the piactical conditions necessary for accurate determinations. There ’ivere numerous reports of colorimetric determination of phospholus. Most methods depend on the formation of phosphovanadomolybdate complex. Gericke and Kurniies (50) described a procedure which was not found by Scheffer and Pajenkamp (124) t o be in agreement with the usual gravimetric procedures. Teague (138) determined available phosphoric acid in fertilizers by combining the water and citrate extracts, followed by a photometric step. Bridger, Boylan, arid l l a r k e y (16) described a colorimetric procedure for total and available phosphoric arid in several different fertilizers. Gee and Deitz (49)described a colorimetiic procedure said to give results to within 1 part per thousand. Other reagents were also used t o develop color in photometric methods. Furukan a, Oida, Sakamura, Kasuga and Yoshikawa (44)compared several reagents. Takahashi ( 1 3 6 ) developed a color v i t h metol reagent (prepared from p-L\leHXCGH,OH and sodium bisulfite) and ammonium molybdate. Ikeda ( 6 5 ) used sodium sulfite-bisulfite, sodium thiosulfate, ammonium molybdate, and sodium acetate. Furukawa, Sozue, and Toshikan-a ( 4 3 ) used sodium molybdate and 3-methyl-p-aminophenol in sodium bisulfite, and Kato and Ooizumi ( ? I ) used ammonium molybdate either with or viithout pyrogallol. Other instrumental methods vere also used by a number of workers. Bustin, Denson, and Epps (5) found that a photometric method for available phosphorus pentoxide was comparable in accuracy t o the official AOAC method. Dippel, Bricker, and Furman ( 2 9 ) used a flame photometric procedure. Sakamura and Kishimoto ( 9 5 ) and Xovak ( 9 8 ) used a method in which excess molydenum mas determined by a polarograph. Xagai, Kanazarr-a, and Ishii (94) described a method of determining citric acid solubility of a mixture of calcium cyanamide and fused phosphate fertilizer. Krumm ( 7 7 ) defined limitations of the citric acid solubility method when applied t o phosphate rock. H e concluded that this method bears no relation t o the actual availibility of phosphate rocks in field practice. Shapiro ( 1 2 7 ) described a simple field method for determination of phosphate in phosphate rock, which was accurate to within 5% of the phosphate content. Etienne (55) separated nieta-, pyro-, poly-, and orthophosphates by progressive precipitation of their barium salts. POTASSIUM
T h e results of analysis of several fertilizers by numerous collaborators who used the hO.%C method, the Perrin method (103)) and the flame photometric method were compared by Ford (38-40); the results XTere in good agreement. The presence of minor elements (copper, manganese, cobalt, and others) resulted in variations in the results b y the Perrin and LindoGladding methods (4)but not by the flame photometric method. Gravimetric procedures were reported by a number of workers. Eser (32) reported that a large error in the Cramer and Tisdall method ( 2 4 ) is due to the high solubility of potassium sodium cobaltinitrite; this can he avoided by using a saturated solution of the precipitate for Ivashing. Chiha ( 2 0 )reported that an error in the cobaltinitrite method is caused by the presence of ammonium salts in the reagent. The method based on precipitation of potassium as the 12-phosphomolybdate TTM described by Belcher and Robinson (8). Berlihout (9) described a modification of the method of Raff and Brotz (112)which precipitates potassium as a salt of tetraphen) lhoron. Procedures were deqcril,Pd by Flaschka, A4min,and Holasek ( 3 6 )and Rudorff and Zannier (120, I S l ) , who titrated potassium tetraphenylborate iodometrically. -4 volumetric method depending on iodometric titration of potassium diliturate with copper sulfate \\-as studied by Press and Murray
633 (106). Ievin’sh and 0201 (63) precipitated potassium with a reagent consisting of tartaric acid, pyridine, and alcohol followed by titration with sodium hydroxide. Kumerous workers studied the flame photometric method. 3Iehlich and Monroe (86) investigated statistically reasons for large variations in results of a collaborative study. Schall and Hagelberg (122) analyzed representative grades of fertilizers made from reagent grade ingredients; they concluded that the results were comparable in accuracy to those by the AOA4C method. Crooks ( 2 5 )described a rapid flame photometric method suitable for screening mixed fertilizers. Eggertsen, Kyld, and Lykken ( S I ) found that interference caused by the preeence of acids and salts in the test solution can be eliminated by using a buffer such as lithium chloride. Blackwell, Yeager, and Kraus ( I S ) analyzed 28 samples of fertilizers and found t h e results as accurate as those by the dO.-iC procedure. Various other methods for potassium included an indirect polarographic method of Monnier and Besso (88). Conductometric methods were used by Udovenko and Pasovskaya (141), who titrated a sodium picrate solution, Keiner and Koller (143), who titrated a precipitate of potassium chlorate, and Yasumori (148), nrho titrated with sodium dipicrylaminate. Radioactive measurements were used by Scheel(12S) and Zlotowski (152). A turbidimetric method was used by Olson (99). CALCIUM
Work on gravimetric procedures of calcium deterniination who prevented precipitation of included a study by 3Iatsuo (8~7)~ magnesium in t h e oxalate method by careful control of precipitation conditions. Gautier and Renault (48)found an error in the determination of calcium as sulfate because of inclusion of calcium oxide or carbonate; this was prevented by treating t h e oxalate with nitric acid before addition of sulfuric acid. Graue and Zohler (56) gave detailed directions for determination of calcium and magnesium in ores and slags with uranildiacetic acid; interfering heavy metals Trere removed by precipitation with ammonium sulfide in t h e presence of ammonium chloride. Shinkai ( 129) determined calcium and magnesium in dolomite by using barium hydroxide instead of calcium hydroxide to precipitate magnesium hydroxide; they also described a method in which calcium oxalate was titrated Tvith potassium permanganate. Several workers studied volumetric methods in which chelating agents were used. Berkhout and Goosens ( 1 0 ) determined calcium and magnesium in fertilizers by precipitation of calcium oxalate in the presence of acetic acid and titiation of the filtrate with Complexon [(ethylenedinitrilo)tetraacetic acid]. Banks (6) confirmed that t h e ethylenediamine tetracetate method for calcium and magnesium is rapid and reasonably accurate. Pribil and Fiala (108)precipitated calcium oxalate in the presence of disodium ethyIenediamine tetraacetate and determined the calcium as sulfate by manganometric titration or Complexon titration. Calcium, magnesium, and iron in limestone were determined by Chenp, Kurtz, and Bray ( 1 9 ) by digestion in perchloric acid and titration with disodium (ethylenedinitrilo) tetraacetic acid. Jordan and Robinson ( 7 0 ) determined calcium and magnesium in limestones by titration Tvith disodium ethylenediamine tetraacetate. Brunisholz, Genton, and Plattner (18) determined calcium in t h e presence of magnesium and phosphate ions by passing the solution through an ion exchange resin and titrating with disodium ethylenediamine tetraacetic acid. Stephens (134) determined calcium and magnesium by titration with Complexon. Calcium in magnesite was determined by Flaschka and Huditz (37) by precipitation with S-hydroxynaphthalimide. Goto and Kakita (54) determined free lime in slag by digestion with ethylene glycol and titration with hydrochloric acid. Kurmies
634
ANALYTICAL CHEMISTRY
(7-8) determined calciuiii in Thomas phosphate b y precipitation in the presence of ammonium acetate and titration IT ith potassium permanganate. Several instrumental methods for calcium n ere described. Williams and Moser ( 1 4 6 ) w e d aniinoniuni purpurate in a colorimetric method. -4shizair.a ( 2 , 3 ) used anthranilic acid in a colorimetric method. Prihil and VicenovA (111) used a polarographic method based on the interchange between the complexonate of zinc and calcium. IIusha ( 9 1 ) used a high frequency titration with aninioriiuni o ~ a l a t e . Gjeins and Lydersen ( 5 3 )found that the reduction in calcium flame intensity due to aluminum in the flame photometric method n-as eliminated by precipitation of the aluminuiii mith benzoate. Ikegami and lfatsuo (65) studied the effect of manganese in the determination of calcium in basic slags.
M4NGAN ESE
.\IAGNESIU>l
Smith and Olney (131-1.33) reported results of collaborative studies on determination of magnesium by A O h C procedures and chelate procedures; they also studied the effect of particle size of the fertilizei~. .\ review of gravimetric procedures for determination of small quantities of magnesium ivas publkhed by Bourdon (14). A titrimetric procedure for magnesium in dolomite \vas described by Remy-Gennete (118). Tanimoto and Morita ( 1 3 7 ) described a colorimetric procedure with Titan Yellow. Zan’ko and Panteleeva (151) used an amperonietric procedure with 8-quinolinol (oxine). Pasovskaya and Udovenko (102) described four conductometric methods: titration of an aqueous alcoholic solution of the sulfates by barium hydroxide and barium acetate; titration of thip solution by barium hj-droxide, (p-nitrobenzeneazo)-1-naphthol, and barium acetate; titration of this Polution by barium hydroxide: and a similar method, except that a graphical technique was used. Several who studied calcium also described procedures for magnesium (6, 10, 19, ,56, 70, 129, 1.94). SULFUR
Sulfates were determined in the presence of iron by Gandolfo 147) by treatment of the solution with hydrochloric acid and potassium iodide, addition of sodium hydroxide, and precipitation of barium sulfate. Sulfur in blast-furnace and open-hearth .lags n-as determined by Morinioto (50) by a combustion method in which iron porTder or boric oxide was added to the sample. Sulfur in ammonia synthesis gases was estimated by Thampy 1139) by passing them through alkaline potassium permanganate rolution and an aqueous alcoholic solution of potassium hydroxide and hydrogen peroxide. BORON
Berry (11, 1 2 ) reported the results of several collaborators n h o analyzed three samples of mixed fertilizers by tnoAO.4Cmethodq, the 1-irginia modified method and a spectrometric method. The less soluble borates in fertilizers were determined by Saftel and Fajans (92). Boron in wperphosphate, Rhenania phosphate, and Rochling phosphate was determined by three different methods by TT7ehrmann (142). Polheim (205) determined borox in phosphates by precipitating the phosphate n i t h ferric chloride and calcium carbonate before titrating the horon. Schutz (126) described an ion chromatography method. Singh (130) uqed a spectrochemical method. Mitrovic (81)determined the lower limits of sensitivity in spectrochemical determination of boron. Otting (101) published a coniprehensivr treatise covering a critical investigation of the various method. of determining horic acid in plant and animal product..
Luiggi (80) used hydroxylamine, hydrazinc, and semicwbazitlc to reduce manganese to the divalent state to separate it from iron and rare earths before proceeding xvith the analysis. Gibaud ( 5 1 ) used an iodometric method in which a mangane+e complex with triethanolamine was reduccd by potaasiuin iodide and titrated, Seelakantam and Part1i:isarathi (97) uard a volumetric niet,hod in which manganese oxinate was precipitated, dissolved in hydrochloric acid, and titrated n i t h potassiuni bromate-bromide solution with indigo carmine as an indicator. Smith (131) reported collaborative analyses of manganese i n fertilizers. COPPER
Hall)im>k ( 5 7 ) determined copper and zinc in fertilizers by :I polarographic method which gave results comparable n-ith those obtained by the AOAC method. Divis and Skoda (.YO)used a colorimetric method with the methyl ether of 2-isatosime. ZI3C
Chelating agents were used by Flaschklt (Sd), I
