(732) Yankov, L. K., Tsutsulova, A. M., Stoyanova-Ivanova, B., Nikolov, Khr., Riv. Ital. Essenze, Projumi, Piante O.fk., Aromi, SapOni, Cosmet., aerosol^ 51, 571 (1969). (733) Yano, K., Flavour Ind., 1 , 328 (1970). (734) Yayashi, s., Yano? K., Matsuura~ T., Tclrahedron Lett., 1968, p 6241. (735) Yoshida, T., Higashi, F., Ikawa, S., Nippon Sakumotsu Gakkai Kiji, 37, 118 (1968). (736) Yoshida, T., Ikawa, S., Morisada, S., ibid., p 565.
(737) Yoshida, T., Muraki, S., Kawamura, H., Komatsu, A,, Agr. Biol. Chem. (Tokyo), 33, 343 (1969). (738) Yoshihara, K., Ohta, Y., Sakai, T., Hirose, Y., Tetrahedron Lett., 1969, p 2263. (739) Yunes, R. A., Talenti, E. C., Rev. Fa. Zng. Quim.,univ.Na. Litoral, 35, 11 (1966). (740) Yune;, R. 4.9 Talenti, E. c. J.7 Terenzani, A. J., zbid., 36, 49 (1967). (741) Yurina, R. A., Dembitskii, A. I)., Ignatova, L. A., Goryaev, M. I., Zzv.
Akad. Nauk SSR, Scr. Khim., 19 (5), 66 (1969). (742) Zavarin, E., Critchfield, W. B., Snajberk, K., Can. J. Bot., 47, 1443 (1969). (743) Zelenetskii, N. N., Dzhashiashvili, Sh*, N * s*,Gel’perin? N. I., Maslo-Zhir. Prom., 35 (8), 19 (1969). (744) Zemanova, D., Zeman, I., Veda Vyzk. Prum., Potravin., 19 (Pt. l), 61 (1969). (745) Zodl, A., Bull. Trav. SOC.Pharm. Lyon, 12 ( l ) ,41 (1968).
Fert iIizers Charles W. Gehrke, University o f Missouri, Columbia, Mo. 6520 I
T
covers the literature reported from Jan. 1, 1969, to Dec. 31, 1970, and includes procedures recorded in readily available journals, in Chemical Abstracts, and in Analytical Abstracts. Some selectivity has been exercised to include only those procedures especially pertinent or those which, in the author’s judgment, could be adapted easily to fertilizer analytical problems. HIS REVIEW
OFFICIAL METHODS
The Association of Official Analytical Chemists (AOAC) in 1968 took the following actions (22): (a) expanded the sampling of bulk fertilizers to include railroad cars; (b) revised the method of sampling liquid fertilizer; (c) adopted a new volumetric quimociac procedure for the total, citrate-insoluble, and available phosphorus; (d) adopted a new sodium tetraphenyl boron method for potassium based on the neutral ammonium citrate extract; and (e) adopted methods for determining volume weights, water holding capacity, and air capacity of peat materials. I n 1969 the AOAC (23) adopted as official first action the following procedures: (a) comprehensive nitrogen method by Gehrke et al.; (b) Raiiey powder method for nitrogen; (c) alkalimetric quinolinium molybdophosphate method for water-soluble phosphorus; and (d) spectrophotometric method for water-soluble phosphorus. The AOAC repealed the following methods: (a) reduced iron method for nitrogen, 2.0462.047 and (b) chromium powder method for nitrogen 2.048-2.049. I n addition, 19 methods were declared surplus. The 11th Edition of the Oficial Methods of Analysis of the AOAC was published in the fall of 1970 (46). The Fertilizers section consists of 26 pages 64R
covering sampling and analyses of fertilizers. Included are some new sections on the analysis of peat samples. WATER
Water in phosphoric acid was determined by in situ coulometric generation of Karl Fischer reagent with automated end point detection (26). Samples sizes were from 50 to 150 mg, with a 20 min analysis time. The mean and the precision at the 99% confidence level varied from 0.43 f 0.05% for superphosphoric acid to 36.8 + 0.81% for untreated 10-34-0 base solution; and for polished wet-process phosphoric acid, 16.49y0 f o.19y0 compared to 16.70 i 0.64 by azeotropic distillation. The method is applicable to all materials which normally do not interfere with the Karl Fischer reagent. Duncan and Brabson (9) analyzed for free water in fertilizer by extraction of water from the samples with 1,4dioxane followed by titration of the extracts with Karl Fischer reagent. The total water was determined by azeotropic distillation of water and n-amyl alcohol from its mixture with the sample and titration of the water in the distillate with Karl Fischer reagent. The hydrate water was calculated as the difference between the total and the free water. The analysis for water in the potash industry was studied by application of the Karl Fischer titration method (60). The technique was especially useful for materials with low H20 contents. Deviation of the titration values from those obtained by using a drying oven method occurred primarily with samples having high clay and sediment contents. The Fischer reagent was also used to measure water in fertilizer and materials insoluble in methanol (20). The
ANALYTICAL CHEMISTRY, VOL. 43, NO. 5, APRIL 1971
fertilizer was finely ground with care t o prevent loss or gain of moisture. An apparatus was designed to grind the sample under methanol by a high speed cutter, with the determination being conducted in the same vessel. The Fischer reagent was added automatically and the end point detected by a sensing electrode. A microwave apparatus was used for the determination of water in slurries (48). A rotatable plate allows the placement of the samples in a wave guide, or a hornplate. This makes possible the examination of samples containing high levels of water in special specimen tubes. I n a study to determine the critical relative humidity of mineral fertilizers (55), the $ow point was determined for 14 common N, N-K, P-K, N-P-K, 18K (33-50yOK), and K-Mg fertilizers with a humidity sensor. Measurements at 2030 “C indicated that Ca-IC”aN03, certain multi-nutrient fertilizers, and some with low K content were especially hygroscopic. Mixtures were often more hygroscopic than their constituents separately. The critical humidity (70%) was below the mean yearly humidity. These fertilizers should be protected against the effects of humidity during handling, transport, and storage. The presence of water in fertilizer causes the existence of a water vapor pressure, which conditions the transfer of moisture between the fertilizer and the atmosphere. A new technique was proposed (58),using psychrometers to continuously measure the water vapor content of a current of gas passing across a mass of fertilizer, under conditions such that there is moisture equilibrium between the gas and the fertilizer. The vapor pressure of a fertilizer changes gradually with time. This phenomenon is related to the behavior of the fertilizer during storage.
NITROGEN
An extensive collaborative study was conducted to evaluate a comprehensive nitrogen method developed by Gehrke et al. (13) and a Raney powder method ( 2 ) for acceptance as official methods of the AOAC by Rexroad and Krause (63). Twenty-nine laboratories participated, 10 samples were used, and the new methods were compared to the official method 2.045 (sulfuric-salicylic acid) (46). Evaluation of the data and overall consideration led to the recommendation that both new methods be adopted as official methods for determination of total nitrogen in all fertilizer samples. The literature cited includes data covering ruggedness tests, extensive research, and applicability to samples with high C1/N03 ratios or with a combination of nitrate and organic materials. An automated spectrophotometric method, utilizing Technicon AutoAnalyzer modules, has been developed for the rapid, accurate, and precise analysis of total nitrogen in water and dilute acid soluble fertilizers developed by Gehrke et al. (14). The Missouri Automated Nitrogen Method (MANM), using manual reduction, is now being used routinely in the Missouri State Fertilizer Control Program as the screening method on all fertilizer samples. I t has also been shown that complete automated reduction of nitrate can be accomplished within the flow system using a CrII-TiIv catalyst combination. The AMANMmethod with automated reduction has been found to be rapid, accurate, and precise for water and dilute acid soluble liquid and solid fertilizer samples. Woodis et al. (74) observed that the effect of decomposition of the polyethylene envelopes of Kel-Paks in the presence of salts of metallic reductants caused rapid fluctuations and excessive rise in temperature with consequent loss of ammoniacal N . Complete Kel-Paks can be used without difficulty in methods such as 2.044 (45) which do not use metallic reductants, but only the contents of the Kel-Paks without the envelopes should be used when Raney catalyst or Cr powders have been used to reduce nitrates. An automated spectrophotometric method utilizing the Technicon AutoAnalyzer was developed for the simultaneous determination of urea, ammonia, and ammonium nitrate in low pressure and direct application nitrogen fertilizers by Karl Wrightman (76). Ammonium ion was determined by reacting it with alkaline phenol and hypochlorite to form a blue compound closely related to indophenol. The amount of NH4N03 was determined by measuring a brown addition compound (FeS04.NO) resulting from the reaction of FeS04 and NO. Urea was determined by the for-
mation of a yellow addition product with p-(dimethylamino) benzaldehyde in mildly acid medium. An extremely broad range of concentration was used with high precision and accuracy obtained for ammonia and ammonium (w/w), and urea nitrate from &SO% from 0-3570 (w/w). Rommers and Visser (64) have modified the well-known spectrophotometric determination of N as NH3 to produce a blue colored indophenol. They used a chloramine-T solution, a phenol solution, and a HsB03 medium for color development. The standard deviation is 0.0013 ppm a t a level of 0.2 ppm N in 50 ml of the color-developed solution. The method is applicable to 0.05-20 pg of N. The solution obtained after color development is suitable for solvent extraction with iso-BuOH. The determination of ammonia nitrogen in fertilizers containing urea or ureaaldehyde condensate has been published by Niedermaier He used a saturated K2C03 solution for adjusting the alkalinity. The evolved NH3 was removed in a stream of air and adsorbed in 0.1N H2SOa. The liberated NH3 was determined titrimetrically. Tsap et ul. (69) showed that ammonia-N of the soil and fertilizers was determined by titration with NaBrO according to: (NH4)2SO1 3NaBro 2NaOH + N1 3NaBr Na2S04 5H20. The end point was determined amperometrically, Groeneveld and den Boef (16) determined the concentration of nitrate in fertilizer with chromium (11). The excess of Cr (11) was titrated with 0.2NK1O3. The standard deviation is 'V 0.5%. Urea, phosphate, and NH4+ did not interfere. Morris et al. (4.2) presented a comparison of the automatic Dumas and Kjeldahl methods for the determination of total nitrogen in fertilizers. Representative N-P-K fertilizers were analyzed for total nitrogen by the automatic Dumas method, using a tungstic oxide catalyst-assisted combustion a t 900 OC, and by the macro Kjeldahl method. The automatic Dumas method gave slightly higher results than the Kjeldahl method; however, a statistical evaluation of the experimental data showed that the Kjeldahl method was generally more precise. Katz et al. (29) have developed a procedure for the determination of water insoluble nitrogen which did not require alteration of the sample by grinding. Samples of the fertilizer were washed in a column with the equivalent of 100 inches of water. The residual nitrogen was then determined by conventional Kjeldahl procedures. The procedure was as reproducible as the present official method but was applicable to all types of sources of water-insoluble nitrogen. Since grinding was eliminated, particle size-solubility relationships and coatings
(a).
+
+
+
+
+
were not affected as compared to field application. Leicknam et ala (36) investigated an isotopic analysis of nitrogen by using optical spectrometry. The isotope content can be determined in N 10 min, to within =t39;b near the natural abundance. The isotopic ratio is obtained by an analysis of the spectra recorded between 2992 and 2975 A. This method is applicable to the analysis of ammonia salts, fertilizers, and plant materials. Doty et al. (8) have investigated the application of neutron activation analysis to the determination of nitrogen in various feeds and feedstuffs. Samples were bombarded with fast neutrons to induce the *4N (n, 2 n) laN reaction. 1 3 3 is a positron emitter with a 10 min half-life. The positrons annihilate in or near the sample to produce 0.51 Mev gamma rays, which are then counted in a detector system. Phosphorus and silicon interfere in this analysis. The commonly used method for determination of biuret by reaction with Cu salts in alkaline solutions cannot be used for analysis of complex fertilizers. Makarevich and Koyander (38) have developed a method for determination of biuret on the basis of the formation of a yellow complex with nickel. The absorption maximum is a t 265 nm. The content of biuret was read from standard curves. Mishra et al. (40) have developed an indirect polarographic method for the estimation of micro amounts of biuret in commercial urea. Cd (11) gives a reversible polarographic diffusion wave having Eljz = 0.73 V in NH3 buffer (pH 9.2). Urea, even if it is present in a 100-fold excess, has no effect on the reduction wave. Singhal et al. (63) used atomic absorption spectrophotometry for the estimation of low contents of biuret in urea. A deviation of only =t1.201, was found a t 20 ppm. The biuret is reacted with Cu(0H)z to form a Cu-biuret complex. Though the stoichiometric ratio of CU to biuret was not obtained, a linear relationship was found between the absorbance and the biuret concentration. PHOSPHORUS
The alkalimetric variation of the gravimetric quimociac method was shown by collaborative testing (6) to be accurate and precise for determining total phosphorus, citrate insoluble phosphorus, or direct available phosphorus. The method was recommended for adoption as official first action. A study using the official vanadium phosphomolybdate spectrophotometric method to determine water soluble P20bin fertilizer showed t h a t incomplete recovery may occur if a substantial portion of the P20sis present as short chain linear polyanions (49). Minor modifications of the method were recom-
ANALYTICAL CHEMISTRY, VOL. 43, NO. 5, APRIL 1971
65 R
mended, including the use of a greater volume of acidulant and a more precise definition of the term “incipient ebullition.” Hoyt and Jordan (21) reported a n automatic colorimetric method to simultaneously determine phosphorus, iron, and aluminum in phosphate rock and various solid and liquid fertilizer systems. A combination of in situ sample dilution technique with a sample splitting technique resulted in a n analysis rate of 60, 90, or 120 determinations per hr (20, 30, or 40 samples per hr with 3 elements per sample). Phosphorus was determined in the molybdovanadophosphate complex a t 420 nm. The precision and error were better than = k l % relative throughout the range of 0.1 to 75% Pzos. Bruna et al. ( 3 ) determined phosphate with ammonium molybdate, then extracted the molybdophosphate complex with a n organic solvent mixture by using azPas labeled reagent. Two manually controlled, semi-automatic rigs were developed and used to determine sulfate and phosphate in 10-15 mill at concentrations ranging from a few ppm to several thousand. The sensitivity was high, and the precision was -1%. Application of the method to the determination of phosphate in fertilizer was described. A wide-range automatic P205method was presented by Jordan (24). The method analyzes phosphate from 0.01 to 7.5 mg P205 per ml without range expansion aiid with in situ dilution. Parameters involving elimination of samplewash crossmixing and modification of known published technology were described. Precision at 40 samples per hr throughout the concentration range of 0.1 to 7501, was better than =ko.3y0 relative and accuracy was better than O.4y0 relative. Homogenized granular fertilizers, diluted liquid fertilizers, and raw materials in fertilizer plants were analyzed for phosphate and other components by automatic analyzer systems (31). The physicochemical and mechanical properties of 7 superphosphates from various raw materials were studied from different plants in the USSR in 1965 (34). Data were given for the contents of available P205, insoluble P&, free moisture, granulometric compositions, caking, hygroscopic points, and mechanical properties. Powdered simple superphosphate was the least free Bowing and had the greatest tendency to cake. Hartwell and Hewitt (19) conducted a collaborative study on the effect of a washing technique in the determination of citrate insoluble and available P205in triple superphosphate. Results showed differences of 0.11 to 1.51y0in direct available phosphorus from 8 samples, when a n “active” versus a “static” wash 66R
was employed in the initial step (removal of water soluble phosphorus). The most variation was noted with samples containing more than 1.5% citrateinsoluble phosphorus. The average values for citrate-insoluble phosphorus were 1.42y0 with the active wash and 1.21% for the static wash (std deviations were 0.15% and 0.19%, respectively). The authors recommended adding a precautionary note to the AOAC method 2.029 or 2.037 when washing to remove water-soluble phosphorus. Water-soluble P205was determined in polyphosphates and fertilizer materials (33). Samples were extracted by grinding 1-g samples, shaking 3 hr with 100 ml distilled H20,and diluting to 250 ml with distilled H20. The insoluble residue was filtered off with a No. 2 filter disk and 2-6 fine filter papers, and analyzing the filtrate for soluble P only if transparent aiid cloud free. P was determined by hydrolyzing the pyrophosphate with HN03, precipitating with magnesia, and weighing as Mg2P207. A rapid method for the determination of water-soluble phosphate in soils and fertilizers as the Zn iYH4P04 was described (41). The phosphate solution was boiled with a n equal amount of dia standard solution of lute “,OH, ZnSOl was added, held 30-60 min, centrifuged, and the precipitate washed with 1% NH4Cl. The Zn in the precipitate was determined by titration with EDTA in NH4Cl-NH40H buffer, using Erichrome Black T indicator. The amount of phosphate was calculated from a n equation given. Discrepancies in the analysis of superphosphate for iron, aluminum, and phosphorus were found to be related to the digestion procedure used for sample preparation ( 5 ) . Various acid digestions and combination acid-base digestions were used. The expected data were obtained when the acid digestion was preceded by a highly caustic digestion. The residue from 1+1 HC1 digestion was largely composed of iron, aluminum, and P205that closely fits the structure A10.7Fe0.3H2P3011with most of the Mg and M n in the acid soluble fraction. Chemical and atomic absorption data were combined to confirm the structure of acid-insoluble material identified by X-ray diffraction analysis. Two other methods were used to determine P205 in phosphates, phosphorites, and liquid fertilizers (67). Phosphate ions were determined by amperometric titration with HgN03 and by precipitation with molybdate followed by titration of the molybdate with Complexon 111. Both methods gave good results, even in the presence of Ca2+, Mg2+,Ala+,and Fea+. Singhal et al. (62) estimated P in rock phosphate by its depression effect on
ANALYTICAL CHEMISTRY, VOL. 43, NO. 5, APRIL 1971
the atomic absorption of Ca. Interfering ions were removed with amberlite IR-l20(H+). Fluorine does not interfere at low concentrations but depresses Ca absorption at high concentrations. Results showed good agreement with those of chemically analyzed samples. The same authors analyzed P up to 6 ppm by its depression on the atomic absorption of Sr (61). They also used a flame photometric method employing the depressing effect of P on the Ca-0 band (622 nm) in a coal gas flame (57). Cation interferences were removed again by a cation exchange resin; and a n addition method instead of the calibration method was used. The bending of the interference curve with Ca (toward the concentration axis) was eliminated by adding 1000 ppm K. Results were in good agreement with those obtained from other methods. A study was made of citric acid-soluble P2Or in fused defluorinated phosphorites (51). IR spectra of the samples a t 550-560 and 600 cm-’ showed two clear absorption maxima for the less soluble crystalline material, and only one broad maximum for the more soluble amorphous samples. A “splitting function” was defined based on the absorption at 560, 580, and 600 cm-1, which was linearly dependent on the citric acid-soluble P20a. This was used to analyze this material rapidly and with sufficient accuracy. 1IcKinney and Rosenberg (37) used X-ray diffraction to analyze for phosphorus in phosphate rocks. A model was developed for using a small computer to correct for matrix variation from each of 6 elements in the samples. Sample preparation, standardization, and computer programs for the calculations were discussed. Direct thermometric analysis was used to determine phosphate in fertilizers (56). The analysis was conducted by adding a reagent which reacts with the phosphorus, aiid measuring the temperature variation of the sample during the reaction. Methods to compensate for heat loss to the ambient atmosphere and secondary reactions were described. Results were obtained directly in per cent. The relative error was generally less than 1%. Several elements can be determined simultaneously, with a single analysis requiring 30-60 min. A cell for the digestion of solid materials by means of a solvent was described ( I ) , with means for introducing the sample, digestion with stirring, and removing the liquor for analysis. This can be used to determine the composition of phosphate rock. POTASSIUM
A collaborative study was conducted on a modification of the official STPB
method (2.085) for K20 in fertilizers in 1968 (16). The modified method uses a n aliquot from t h e direct available P2Os extract, thus eliminating a separate sample weighing and solution preparation. This automated method for potassium in fertilizers was collaborated again in 1969 (17). The method utilized basic Technicon equipment and was a modification of the method published by Ussary and Gehrke in 1965 (71). The collaborative study showed promise for the automated method but lacked sufficient participation from laboratories having AutoAnalyzer equipment. A repeat of the 1969 collaborative study was conducted in 1970 (18) with excellent participation. Samples were sent to 12 laboratories and 9 complete sets of data were returned. The study was designed according to the plan of closely matched pairs by Youden (78). Single determinations were made on each sample by the automated flame photometric method (17), and by the official S T P B method 2.085. The means and standard deviations from the automated method compared favorably to those by the official STPB method. This modified automated flame photometric method of analysis was adopted as a n “official AOAC method of analysis” a t the October 1970 AOAC meeting. A group of Russian scientists (79) reported a rapid titrimetric method for the determination of %K20 in industrial fertilizer samples. Semimicropoteiitiometric titrations were carried out on the respective samples with a n LP5pH meter and a glass-calomel electrode system with a 10-ml microburet. The dried 0.1-0.2 g sample is dissolved in 0.5 ml H20,and heated to boiling. Et4NOH, prepared according to Kreshkov, and 20 ml EtOAc are added. The mixture is stirred for 1 minute, and is titrated with standardized methanolic HClO4 from -400 V to f600 V. The equivalence point occurs between +200 V and +300 V. Time required for a single analysis is 20 minutes. Satisfactory agreement was found for a series of titrimetric, gravimetric, and flame photometric values of K as %KpO in fertilizers containing 10-4370 K20 by weight with a n error of &2%. A German scientist, Teicher (66), reports a potassium determination by the volumetric tetraphenylborate method with electric end point indicator (dead stop method). After the precipitate of K tetraphenylborate had formed, the excess N a tetraphenylborate was titrated with 0.02M T1No3. If chelaters are present, the sample must be ashed. The procedure takes approximately 30 minutes and the error was &0.5’%. Ostmann et al. (48) describes a potassium determination in fertilizers by the electrometric titration method of H. J. Schmidt (1957) , involving addition of
excess NaBPhr and titration with T1NO, of the excess after digestion. The end point was detected by the change in the polarization resistance of a n amalgamated Ag double electrode. A correction curve was obtained by analyzing synthetic standards. The absolute standard deviation was 0.08% for 1422% K 2 0 in fertilizers. The basic principles of neutron activation analyses were applied by Eckhoff (IO) in the study of agricultural samples. A uniform irradiation and counting of 15 minutes irradiation at 50 kw power, 5 minutes decay, and 3 minutes count yielded the required analytical information. Seven elements, including potassium were routinely determined. Ordogh (47) also gives some selected activation analyses which are particularly useful in the fertilizer industry for the determination of K, P, and N. The use of highly acidic cation exchangers (KU-2) for a quantitative analysis of nitrogenous and potassium fertilizer ingredients has been described (60). Commercial resin KU-2 was changed to the H+ form by the B. V. Aivazov method (1968), and a column of 25.0 X 0.9 cm dimensions was filled with resin to a height of 15 cm. Ten ml of the fertilizer solution were passed through the column at a rate of 5 ml/ min. The resin was washed with 40 ml of distilled HzO at a rate of 10 ml/min, then the combined filtrates were titrated for the respective ingredients with 0.2147 NaOH in the presence of phenolphthalein. This method is simple for the determination of NI14+, C1-, and K + in fertilizer ingredients and is accurate to within 12.5%. MICRONUTRIENTS
An X-ray fluorescence method was described for the determination of iron in phosphate rock (12). The intensity of the F e K a radiation from the samples was measured without interference by other components and read against a calibration curve prepared from pure reagents that had the average composition of phosphate rock (without Fe203) plus varying amounts of added Fe203. Results by this method, in the range of 0-1% Fe, were nearly identical with, but slightly higher than those by a colorimetric method. Melton, Hoover, and Howard (39) proposed a fast and accurate method for determining water-soluble boron in fertilizers. The water-soluble B was extracted into a mixture of 2-ethyl-1,3hexanediol and methylisobutyl ketone for determination by atomic absorption spectrophotometry. The extraction procedure brings the fertilizer sample, water, and solvent in contact simultaneously. The organic layer which
contained the extracted B was aspirated into the flame. There were no significant interferences from elements commonly found in fertilizers. Takoda and Nakano (66) report enhancing the sensitivity in the flame photometric determination of Na by heating the atomizing chamber of the premix burner. The relative intensity of the emission of Na increased linearly with the temperature of the chamber u p to 50 “C, remained constant up to 80 “C (&fold enhancement) , and decreased slightly at higher temperature. I n the presence of organic solvents, such as EtOH or ILIe2C0, this effect was less prominent. A procedure was developed (52) for the determination of molybdenum in fertilizers based on extraction into chloroform using 8-hydroxyquinoline. The determination is by atomic absorption in the premixed nitrous oxide-acetylene flame. ?\lethylisoamyl ketone was added to the chloroform extract to improve the burning qualities. The method is sensitive and precise but appears to have a positive bias of about 5%. An apparatus for making direct thermometric analyses is described by Sajo (56) for the rapid determination of phosphate, nitrate, and sulfate content of fertilizers. The apparatus incorporates a thermistor in one branch of a suitably arranged measuring bridge and the temperature variation is read on a mobile scale galvanometer. Analysis is executed by adding to the sample solution a reagent which reacts in a selective fashion with the component to be determined and measuring the temperature variation during the course of the reaction. Results are obtained directly in YO. Several elements can be determined simultaneously in the same solution with a single analysis taking 30-60 min. King et al. ( S I ) determined the sulfate content of fertilizers continuously with a n automatic analyzer by a turbidometric technique. Woodis, Johnson, and Cummings (76) reported an indirect chelometric method for the sulfate content in fertilizers. Sulfate was determined by precipitation with a measured excess of lead salt and titration of the excess lead with EDTA. Interfering ions, including phosphate, were removed with ion exchange resins. I n addition to being more reliable, the chelometric method is more rapid than the classical barium sulfate method. When the sample is in solution, a single determination can be made in 90 minutes by the proposed method, compared to a minimum of 4 hours by the gravimetric barium sulfate method. An accurate and rapid method of aiialysis for fluoride in phosphate rocks was reported (21). Fluoride was determined in the sample solution either
ANALYTICAL CHEMISTRY, VOL. 43, NO. 5, APRIL 1971
67R
colorimetrically with the Lralizaranfluoride-blue complex or by measurement with the fluoride electrode at p H 7.0 (Na citrate buffer). The latter method was more precise. Sample preparation methods (11) were also studied and i t was found t h a t only the ion-exchange technique gave consistently low results. Yamazoe et al. (77‘) proposed a spectrophotometric determination of fluoride in fertilizers. To determine fluoride in fertilizers, a colorimetric method in which t h e color was developed by a lanthanum-alizarin complexone reagent was studied. Since elements such as All Fe, or P interfered, it was essential to distill the fluoride as hydrosilicofluoric acid. The acidity of the distillate was neutralized with NaOH before the addition of Alfusone (the mixed reagent of alizarin complexone, lanthanum salt, and buffers) solution. Addition of acetone increased t h e sensitivity and was ~ solution. The optimal at ~ 4 0 of7 the wavelength for the spectrophotometric determination by Alfusone was 620 nm. This method was suitable for determining semimicroamounts of fluoride, and was superior to the thorium nitrate method in its accuracy. Jordan et al. (25) determined total fluoride and/or fluosilicic acid concentrations directly, using the fluoride ion selective electrode, thus eliminatiiig the traditional differential hot and cold titration method. Samples can be analyzed a t 20-30/hr with excellent precision; results are equivalent to those obtained with the standard test procedure No. 13 703-60. Microdeterminations of calcium and magnesium were carried out by Kar (28). Calcium (0.5-1 mg) can be separated from 5 2 0 mg of I l l g on the basis of the selective carrying of Ca by SrS04 in 40-48y0 EtOH media, and individually titrated with EDTA. Varju (72) analyzed for Cu, hln, and F e in processed superphosphate and crude phosphate by extracting with N a pyrrolidone dithiocarbamate aqueous solution, followed by HzS04 decomposition and then examining spectrographically by the rotating disk method. The Cu, Mn, and Fe content of the sample was expressed as t h a t extractable with citric acid, HzO, and respectively. Only a very small amount of the trace elements extracted from the soil by the vegetation can be replaced by the Cu, Mn, and F e content of commercial superphosphates. Also, Schmidt et al. (59), spectrographically determined the Cu, Mn, and F e content of rock phosphates and superphosphates in H2S04,citric acid, and aqueous extracts. The elements studied were enriched by the extraction-separation method of Scharrer and Jude1 (CA, 51, 24576), the separated organic metal complexes were decomposed by HzS04 68R
wet oxidation, and the concentrated HzSO4 solution studied by rotating disk spectrography (Saakacs et al., C A , 64, 4459). The relative error of this method was +8.6’%. There was a positive correlation between the free acid content and solubility of the trace elements. The trace element levels in the superphosphate were not adequate to replace those used by plants. Investigation of the assumed interferences of inorganic and organic compounds in fertilizers on the analyses of Cu and Zn showed that the presence of these compounds had no effect on the determination of Cu by atomic absorption spectrophotometry (68). Results from the analyses agreed well with the results from polarographic analyses. A method for concentrating Co, Cu, and Zn in the presence of ethyl xanthate was developed (56) for analyzing fertilizers by using @-naphthol as the coprecipitation reagent for these 3 elements with simultaneous separation from the other accompanying elements which were concealed by NH4 citrate addition. The proposed method permitted determination of 10-100 ppm of Co, Cu, and Zn. Khakimova et al. (30) reported a method for determining Mo in fertilizers polarographically, after first removing the interfering elements Fe, In, V, etc. by treating the samples with mineral acids and ion-exchange columns. Various fertilizers contained 0.04-1.04 X 10-3% MO. An automated colorimetric method was proposed by Hoyt and Jordan (61) that simultaneously determines P, Fe, and A1 in phosphate rock and various solid and liquid fertilizer systems. Combination of a n i n situ dilution technique for 1’ with a sample-splitting technique results in a n effective analysis rate of as much as 120 determinations/hr (40 samples/hr, 3 elements/sample). I’ was determined a t 420 nm as the molybdovandophosphate complex. F e and A1 were both determined as Ferroii (8- hydroxy-7 -iodo- 5-quinolinesulfonic acid) complexes with the Fe complex determined at 610 nm, and the combined F e and A1 complexes determined at 366 nm. The precision and error were better than *1% relative throughout the range of 0.1 to 7570 PZ05,and u p to 10% Fe203and 10% A1z03. A group of Russian scientists (70) reported a n ion-exchange technique for separating P, Mo, Fe, Mn, Cu, Zn, Al, Ca, and Mg from phosphate fertilizers in HC1 extracts. A combination of KU-2 cation exchanger and a n anion exchanger in its chloride form were used to separate the trace elements prior to analysis. A high concentration of trace elements was attained by passing a large amount of the dilute sample solution through the KU-2 column and then eluting with a small volume of eluent.
ANALYTICAL CHEMISTRY, VOL. 43, NO. 5 , APRIL 1971
A spectral method was proposed (62) for determining M n and Cu from 5 X 10-5-1 X P b and F e from 3 X 10d4-l X lo-*%, and As from 1 X 10-a-l x in H8PO4. Calibration graphs were plotted by using the background as t h e internal standard. The analytical lines were Fe, 3020 1; Mn, 2801 1;Pb, 2833 1;Cu, 3247 1; and As, 2349 A. Satisfactory agreement of the results of spectral and chemical methods was obtained. The mean square error was 10-20%. Teicher (66) determined t h e trace elements Mg, Mn, Cu, and Zn in mineral fertilizers quantitatively by colorimetry, gravimetry, and by atomic absorption spectroscopy. The latter method was less time consuming and more accurate than the others. The diluted HCl extracts of ground fertilizer samples could be sprayed directly into the flame. This method was not sufficient for the detection of I3 and Co. McKinney and Rosenberg (37) developed a method for simultaneously determining phosphorus, silicon, calcium, iron, aluminum, and magnesium in phosphate rock by X-ray emission analysis, using a small computer to correct for matrix variation. A mathematical model was developed which utilizes the X-ray intensity from each of the six elements considered and the mass absorption coefficients of the elements to calculate concentrations. -4ccurate analyses for P, Si, Ca, Fe, Al, and M g were obtained by using this model. REFERENCES
( 1 ) Bauinann, A. N., Roberts, H. H., U.S. 3.449.082. (C1. 23-253: Golmn. 10 June i969,’ Appl. 23 Sep. 1965; 8 pp.). (2) Brabson, J. A., Woodis, T. C., Jr., J . Ass. Ofic. Anal. Chem., 52, 23-30 (1969).(3) Bruna, A., Caldera, P. G., Tarditi, P. L., Brussels, T., Sci. Tech. Aerosp. Rep., 6 (9), 1293 (1968). (4) Cappellina, F., Cappelletti, L., Automat. Anal. Chem., 2, 295-301, Mediad, Inc.: White Plains, N.Y., (1968). (5) Carel, A. B., Jordan, D. E., J . Ass. O$c. Anal. Chem., 52 (3), 577-81 (1969)
(Em).
(6) Caudill, P. R., J. Ass. O$c. Anal. Chem., 52 (3), 587-92 (1969). (7) Docherty, A. C., Proc. Fert. SOC.,No. 104,45-67 (1968). (8) Doty, W. H., Wood, D. E., Schneider, E. L., J . Ass. O$c. Anal. Chem., 52, 953-956 (1969). (9) Duncan, R. D., Brabson, J. A., J . Ass. Ofic. Anal. Chem., 52 (6), 1127-31 (1969). (10) Eckhoff, N. D., Nucl. Sci. Abstr., 22 (19), 39990 (1968). (11) Evans, L., Hoyle, R. D., Macaskill, J. B., New Zealand J . Sci., 13 ( l ) , 143-8 (1970). (12) Funasaka, W., Ando, T., Tomido, Y . , Bunseki Kagaku, 18 ( l ) , 74-5 (1969) (Jap). (13) Gehrke, C. W., Ussary, J. P., Perrin, C. H., Rexroad, P. R., Spangler, W. L., J . Ass. Offic. Anal. Chem., 50 (4), 965-75 (1967). (14) Gehrke, C. W., Wall, L. L., Sr., Killingley, J. S., Inada, K., to be
Dublished in J . Ass. Ojic. Anal. Chem. (1971). (16) Groeneveld, E. It., den Boef, G., 2. Anal. Chem., 238 (l), 19-28 (1968)
(Ger).
(16) Hambleton, L. G., J . Ass. Ofic. Anal. Chem., 52 (3),!566-9 (1969). (17) Hambleton, L. G . J . Ass. 0%. Anal. Chem., 53 (3), 456-6i) (1970). (18) Hambleton, L. G., to be published in J . Ass. Ojic. Anal. Chem. (1971). 119) Hartwell. W. ,I., Hewitt, E. B., J . A s s , Ofic. Anal. Cheni., 52 (5), 946-9 I
11969)
(20j-HeSlop, A. X I Skinner, J. M., Docherty, A. C., Analyst (London), 94 (1121), 681-7 (1969). (21) Hoyt, J. L., Jordan, D. E., J . Ass. Ofic. Anal. Cheni., 52 (6), 1121-6 (1969). (22) J. Ass. Ofic. Anal. Chem., 52, 382-385 (1969). (23) J . Ass. O$c. Anal. Chem., 53, 437 (1970). (24) Jordan, 1). E., J . Ass. Ofic. Anal. Chem., 52 (3), 581-7 (1969). (25) Jordan, L). E., J . Ass. Ofic. Anal. Chem., 53 (3), 447-450 (1970). (26) Jordan, 1). E.; Hoyt, J. L., J . Ass. Ofic. Anal. Chem., 52 (3), 569-77 (1960). (27,) Joseph, K. T., Parameswaron, hf., boman, S. D., Curr. Sci., 39 (7), 145-7 (1970). (28) Karl K . R., Singh, G., Alikrochim. Acta., (2), 388-92 (1969) (Eng). (29) Katz, S. E., Fassbender, C. A., Greenstein, M., J . A s s . Ojic. Anal. Chem.. 53. 808-811 (1970). (30) Khakimova, V. K., Aulesheva, hI., Nabieva, h1. ll.,U z b Khim. Zh., 14 ( l ) , 6-7 (1970) (Russ). (31) King, G. H., Scobie, A. G., Chem. Process Eng., (London), 5 1 (5), 62-3 (1970). (32) Koirtyohann, S. R.,Hamilton, M., to be published iri J . Ass. Ojic. Anal. Chenz. (1971). (33) Kiibasova, L. V., Aleksandrova, G. G., Isv. Vyssh. V’cheb. Zaved., Khim. Khim. Tekhnol., 11 (7), 840-50 (1968). (34) Kurshinnikov, I. M., RIalonosov, N. L., Khim. Sel. Khoz., 7 (0), 668-71 ( 1969). (35) Kuznetsov, V. I., Kurmaeva, T. V., Sb. iyauch. T r , Perm. Politekh. Inst., 44, 63-9 (1968) ( 1 1 ~ ~ s ) . (36) Leicknam, J. P., Middelboe, V., Proksch, G., Analytica Chim. Acta, 40 (3), 487-502 (1968) (Fr).
(37) McKinney, C. N., Rosenberg, A. S., Advan. X-Ray Anal., 13, 125-35 (1970). (38) Makarevich, V. kf., Koyander, A. E., Agrokhimiya, 1, 1 3 9 4 3 (1970)
(Ituss).
R., Hoover, W. L., Howard, P. A., J . Ass. Ofic. Anal. Chem., 52 (5), 950-3 (1969). (40) Mishra, M. B., Banerjee, B. K., Technology, 6 , 3 5 (1969) (Eng). (41) Moghe, V. B., Khetawat, G. K., Mathur, C. M., Sci. Cult., 34 (4),
(39) Melton, J.
186-8 (1968). (42) Morris, G. F., Carson, R. B., Jopkiewicz, W. T., J . Ass. Ogic. Anal. Chem., 52 (5), 943-6 (1969). (43) Nelson, G., Brit. 1, 157, 270 (Cl. Goin) 2 July 1969, Appd. 15, October; 4 PP. (44) Niedermeier, T., Landwirt. Forsch. Sonderk, 23 ( l l ) ,82-91 (1969) (Ger). (45) Oficial Methods of Analysis, 10th Ed., (Association of Official Analytical Chemists, Washington, D.C.) (1965). (46) Oficial Methods o Analysis, 11th Ed., (Association of fficial Analytical Chemists, Washington, D.C.) (1970). (47) Ordogh, M., Atomtech. Tujek, 11 (3), 132-32 (1968) (Hung). (48) Ostmann, 13. J., Landwirt. Forsch., 23 (2), 162-71 (1970) (Ger). (49) Palgrave, 1).A., Paton, T. J., Elson, R., J . Sci. Food Agr., 21 (6), 273-5 (1970). (50) Peterburgskii, A. V., Kulyukin, A. N., Agrokhimiya, 9, 124-6 (1970) (Russ). (51) Poletaev, E. V., Kalmykov, S. I., Kushnikov. Y. A.. Tr. Inst. Khim. N a u k , Akad. Nadk Kaz. SSR, 25, 42-7 (1969). (52) Polivanova, N. G., Fratkin, Z. G., Bogdanova, N. N., Nedolsina, N. P., “Ref. Zh., Khim. Abstr. No. 140-175, (1968). (53) Itexroad, P. It., Krause, G. F., J . Ass. Ofic. Anal. Chem., 53 (3), 450-6
x
(1960\. \ - - - - I .
(54) Rommers, P. G., Visser, J., Analyst (London), 94, 653-8 (1969). (55) Kunge, P., Neubert, K. H., Matzel, W., Kund, P., Albrecht-Thaer Arch., 13 (1). 17-24 (1969). (56) Sajo, I., Interceram, 18 ( l ) , 30-2 (1069) (Eng). (57) Sanyl, R . M., Singhal, K. C., Banerjee, B. K., Technology, 54 (4), 316-18 (1968). (58) Scartazzini, H., Ind. Chem. Belge, 32 (Spec. No. Pt. 2), 384-5 (1967).
(59) Schmidt, H. J., Landwirt. Forsch. Sonderk., 23 ( l l ) , 177-80 (1969) (Ger). (60) Sell, R., Kern, L., Chem.-Zta, ”. Chem.. App., 93 (Z), 67 (1969). (61) Singhal, K. C., Banerjee, B. K., Technology, 5 (2), 117-19 (1968). (62) Singhal, K. C., Banerjee, B. K., Technology, 5 (3), 239-41 (1968). (63) Singhal, K. C., Sinha, R. C. P., Banerjee, B. K., Technology, 6, 95-7 11969). (64) Skinner, J. M., Automat. Anal. Chem., 2, 327-32, Mediad, Inc., White Plains, New York (1968). (65) Takada, T., Nakano, K., Bunsaki Kagaku, 19 (I), 115-17 (1970) (Jap). (66) Teicher, K., Landwirt. Forsch. Sonderk., 23 (111, 177-81 (1969) (Ger). (67) Teodorovich, I. L., Rumyanstseva, L. S., Khim. Sel. Khoz., 6 (8), 633-4 (1968) (Russ). (68) Toyoda, T., Niken Kaiho, 21 (5), 1-7 (1968) (Jap). (69),Tsap, M . L., Seonchik, 0. A,, D yachenko-Okladnyuk I.K. Fr., 1, 54550 (1969). (70) Tsitovich, I. K., Gaidukova, H. G., Khim. Se2. Khoz., 6 ( l o ) , 789-91 (1968)
(Russ).
(71) Ussary, J. P., Gehrke, C. W., J . Ass. Ogic. Anal. Chem., 48, 1095-1100 (1965). (72) Varju, M., Agrokem. Talajton, 18 (21), 313-20 (1969) (Hung). (73) Varju, M., 2. Pflanzenemaehr. Bodenk., 124 (11, 12-18 (1969) (Ger). (74) Woodis, T. C., Jr., Brabson, J. A., Buch, W. G., Jr., J . Ass. Ofic. Anal. Chem., 51 (6), 1290-5 (1968). (75) Woodis, T. C. Jr., Johnson, F. J., Cummings, J. Xi., Jr., J . Ass. Ofic. Anal. Chem., 53 ( 5 ) ,928-30 (1970). (76) Wrightman, K., Advances in Automated Analysis, Vol. 2 (p. 61), (Mediad, Inc., White Plains, New York), (1970). (77) Yamazoe, F., Nzppon Dojo-Hirogaku Zasshi, 41 (l),37-42 (1970) (Jap). (78) Youden, W. J., Stabilized Techniques f o r Collaborative Tests, (Ass. Offic.
Anal.
f 1967).
Chem.,
Washington,
D.C.),
(79) Zagotovskaya, A. A., Aleksandrovich, V. F., Vesti Akad. Novuk Belarus. SSR, Ser. Khim. Novuk, 1, 108-11 (1969) (Russ).
COXTRIIIUTION of the Missouri Agricultural Experiment Station. Journal Series No. 6198. Approved by the Director.
ANALYTICAL CHEMISTRY, VOL. 43, NO. 5, APRIL 1971
69 R
