A new densitometer CS-900, employing the dual-wavelength and the zig-zag scanning method, has been originally designed for the purpose of a direct quantitative measurement of the chromatogram spots developed and separated on a thin-layer plate. It has been proven that the dual-wavelength method can eliminate the baseline noise caused by local irregularities of thin-layer's thickness while the zig-zag scanning method can minimize all feasible errors based on non-uniformity in size and shape of the spot and also can improve the accuracy of the U.V. densitometry of invisible spots.
Repeatability was checked by 1-arninoanthraquinone using the internal standard method to eliminate the spotting errors of micro-syringe. Coefficients of variation were well within 1 to 2% even if the two different thin-layer plates are independently used for the standard samples to make a calibration curve and for the samples to be measured.

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A method of the spectrophotometric determination of small amounts of niobium with 2-(2-thiazolylazo)-5 dimethylaminophenol (TAM) in the presence of triethanolamine (TEA) solution is described.
The outline of the procedure for the determination of niobium with TAM is as follows; Take into a 100-ml beaker an aliquot of the sample solution containing less than 30 μg of niobium. Add 10 ml of distilled water, 1.5 ml of TAM-alcoholic solution and 3 ml of TEA, and adjust the pH to 3.8 with 0.2 M citric acid or 0.2 M disodium hydrogen phosphate solution by using a pH-meter. Transfer the solution to a 50-ml volumetric flask and dilute to volume with water. After the solution has stood for 60 minutes, transfer the aqueous solution into a 1 cm cell and measure the absorbance at 605 nm against a reagent blank..
The niobium-TAM complex is blue-violet in an acidic aqueous solution and is stable for 45 minutes up to 6 hours. The absorbance is constant in a pH range of 3.2 to 3.8. The complex of niobium shows an absorption maximum at 603 nm and the molar extinction coefficient at this wavelength is estimated to be 4.8 × 10⁴. The sensitivity for niobium is 1.9 ×10^-3 μg/cm² per 0.001 of absorbance. The complex of niobium is extremely stable and is obeyed to Beer's law up to 1.2 μg/ml of niobium. The molar ratio of niobium to TAM in the complex was confirmed to be a 1 : 1 ratio by the method of continuos variation.
Titanium (IV), copper (II), aluminum (III), zirconium (IV), iron(III) and carbonate ions interfered with the determination of niobium by decreasing the absorbance.
For the determination of niobium in steel, take 0.1 to 0.5 g of stainless steel into a 200-ml teflon beaker, and 5 ml of aqua regia and dissolve by heating on a water bath. Transfer the solution to a separating funnel with a small amount of water, and remove interfering elements by extracting with methyl isobutyl ketone from 7 N hydrochloric acid solution in the presence of nitric acid. After the treatment of the aqueous solution with sulfuric acid, the solution was made up to 500 ml with water. An aliquot of the solution is used for the spectrometry described above. The coefficients of variation by the present method were 1.4% and 3.6% for stainless steel and carbon steel, respectively. The results of the analysis of niobium were in good agreement with those by the JIS method.

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Aluminum ions interfere with the determination of fluoride by the alizarin complexon(ALC)-extraction method. A method is described for eliminating the interference, in which fluoride ions are liberated by co-precipitating aluminum ions with iron(III) hydroxide at pH 10. Fluoride ions are then extracted into an organic solvent and determined by the ALC method. This method was easier than others, and reliable results were obtained.
The recommended procedure is as follows. A sample solution containing 5 to 50 μg of fluoride and less than 250 μg of aluminum ions is prepared and made up to about 50 ml with water. Five milliliters of 0.1 M iron (III) chloride solution are added and pH is adjusted to about 10 by the addition of 2 M ammonium hydroxide. The solution is boiled for a few minutes, and filtered through a filter paper. Precipitates are washed thoroughly with warm water. The filtrate and washings are combined, and the pH is adjusted to 57 with dilute hydrochloric acid. The solution is transferred to a 100 ml volumetric flask and made up to the volume with water.
A 20 ml portion of the solution is transferred to a 100 ml separating funnel, and 20 ml of lanthanum-ALC reagent solution {prepared by mixing 75 ml of acetate buffer solution(pH 4.4), 25 ml of 0.003 M ALC solution, 200 ml of acetone, 25 ml of 0.003 M lanthanum chloride solution, and about 180 ml of water} is added.
After allowing the solution to stand for about 10 min, 10 ml of N, N-diethylaniline in iso-amyl alcohol (volume fractions≈5%) is added, and the fluorine compound is extracted into the alcohol by shaking for 3 min, and the two layers are allowed to separate by standing. After the drainage of the aqueous layer, the organic layer is washed with about 20 ml of acetate buffer (pH 4.4) solution.
The absorbance of the organic layer is measured at 580 nm using a reagent blank as reference.
By this method, 2550 μg of fluoride ions in the synthetic samples which contained less than 250 μg of aluminum was determined with 94% recovery.

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In the presence of cyanide ion, cupric ion acquires oxidizing characteristics, owing to the formation of stable cyano complexes of copper(I). Under such a condition, phenolphthalin is oxidized to phenolphthalein (red in an alkaline medium).
This color reaction has been used by Maute et al. to determine hydrogen cyanide in acrylonitrile samples. However, the absorbance is affected seriously by pH of the solution, reagent concentration, temperature and the standing time. Therefore, the optimum condition for the operation at each stage of the procedure was investigated, and the following procedure is es tablished.
A neutral sample solution containing 025 μg of cyanide ions are taken in a 25 ml volumetric flask, and 1 ml of 0.5 per cent phenolphthalin in 0.1 N sodium hydroxide solution and 1 ml of 0.039 per cent copper(II) sulfate pentahydrate solution are added. It is made up to the mark with water, mixed, and allowed to stand at 30°C for 2 hours. The absorbance of the colored solution is measured at 553 nm against the reagent blank.
In this procedure, the mole ratio of copper and cyanide in the complex has been confirmed to be 1 : 2 by the continuous variation and mole ratio methods.
Beer's law is obeyed up to 25 μg of cyanide, and the absorbance is stable at least for 24 hours. The apparent molar extinction coefficient based on CN- is about 2.4 × 10⁴ /lmol·cm, and the sensitivity of this method is one-third of pyridine-pyrazolone method. This procedure is applied easily for the determination of cyanide ions in the sample free from interfering ions.

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Trace lead concentrations in natural stream waters and snow were determined by isotope dilution mass spectrometry.
Owing to the extremely low concentrations of lead, cleaning of sampling containers and analytical laboratory wares were carried out with special care. Sampling bottles of conventional polyethylene were cleaned by 2 solutions of cold concentrated nitric acid and two solutions of 1% nitric acid. Chemical wares of FEP teflon and quartz were cleaned by 3-day exposures to two solutions of hot concentrated nitric acid and a 3-day exposure to 1% nitric acid.
After the sampling in the field, samples were kept frozen until time of analysis.
A known amount of ²⁰⁸Pb spike was added to about 200 ml of acidified sample solution and cooked one day at 55°C in order to assure the isotopic equilibration of spike and sample lead. Lead was then extracted with 44 ml of dithizone-chloroform solution(3.8 mg dithizone/250 ml chloroform) at pH7.58.5 Lead was backextracted into an aqueous layer of 10 ml of 0.1 N nitric acid. The lead extraction by 5 mlof dithizone solution was repeated in the presence of 1 mlof 25% ammonium citrate and 2 ml of 1% potassium cyanide at pH7.58.5 After the back-extraction with 1 N nitric acid solution, the sample was mounted on a rhenium filament with silica gel and phosphoric acid. The isotopic ratios were measured in a solid source mass spectrometer (12 inch radius, single focussing, thermal emission source, equipped with electron multiplier) at the California Institute of Technology. The lead concentrations were 0.02 μg/kg in stream water and 3 μg/kg in snow. The error is considered to be within 3%. The lead contamination from reagents was 0.85×10^-9 g Pb per one extraction. No lead contamination was detected from the sampling bottle.

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Spectrophotometric determination of micro amounts of ε-caprolactam in waste water was studied. ε-Caprolactam was converted to hydroxamic acid with hydroxylamine and determined in the form of iron(III) complex of hydroxamic acid. By this method 15 ppm ε-caprolactam in aqueous solution were determined within ±2% error. Amines or acids, which may be present in the waste water of a nylon-6 plant, did not interfere.

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The fluorescent X-ray spectrographic analysis has been made on gallium phosphide layers which are epitaxially grown on germanium substrates by means of the PCl₃ chemical transport method. The measurements have been performed on small size specimens typically having the dimension of 6 mm×6 mm with the thickness less than 50 μm.
The radiations PK_α and GaK_α from the specimens are used for determining phosphorus and gallium in the layers, respectively. Their intensities are normalized by a standard material which consists of a sufficiently thick layer of stoichiometric gallium phosphide.
The calibration curves are drawn for mole fractions ranging from 47.4 to 52.4% gallium according to the calculated data based on the reported values of X-ray mass absorption coefficients, etc.
The results of calculations for the PK_α analysis show that the PK_α intensity is not influenced by the thickness when the layer is thicker than about 5 μm. For the PK_α analysis it is believed that the thickness of the specimens more than about 5 μm can be regarded as to be infinite.
The results of calculations for the GaK_α analysis show that the GaK_α intensity is influenced remarkably by the thickness when it is less than about 50 μm. Accordingly, for the GaK_α analysis the thickness should be known. The thickness are estimated by the analysis of the GeK_α data.
In the case of the PK_α analysis on a series of specimens the experimental mole fractions of phosphorus are distributed around 50% within a range of ±0.5%. In the case of the GaK_α analysis the experimental results are scattered more widely especially with the layers thinner than 10 μm.

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Recoveries of chlorine by the “oxygen bomb” method were investigated by using Chloramine T (sodium p-toluenesulfonchloramide trihydrate) and p-chloroaniline as standard chlorine-containing compounds and by the improved mercury(II) thiocyanate spectrophotometry. The mean recovery was approximately 95% with a coefficient of variation of 2%. When the residual gas was released abruptly after the combustion, the recovery was reduced to about 86%. No significant change in the recovery was observed on addition of water as an absorbent. Chlorine in filter paper was determined by the oxygen bomb method.
The “oxygen bomb” is a useful tool to determine chlorine in organic materials, since the chlorine cannot be recovered entirely by dry or wet ashing methods.
The procedure for the determination of chlorine in filter paper is as follows. (1) Preparation of the sample solution. Fold a sheet of filter paper to form a small square. Wrap up the filter paper in a sheet of rice paper, and tie the parcel with a cotton thread. Put the sample on the platinum capsule, and join the remaining ends of the thread through the coil of a platinum wire as depicted in Bunseki Kagaku, 21, 285 (1972). The whole procedure up to here should be performed with rubber gloves in order to prevent the sample from being contaminated by fingers. Impregnate the sample with a few drops of methanol. Ignite the sample by the same procedure as described in Bunseki Kagaku, 22, 546 (1973). On cooling, release gradually the residual gas spending about 20 minutes. Transfer the bomb washings to a 100 ml volumetric flask and dilute to the mark. (2) Preparation of the iron(III) perchlorate solution. Heat 50 g of iron(III) nitrate with 75 ml of perchloric acid (60%) under a ventilating hood until the fume of perchloric acid is evolved. Filter the deposit with a glass filter on cooling, and wash with a small portion of 1 M perchloric acid. Dissolve 29.6 g of the salt in 33 ml of perchloric acid (60%) and dilute to 100 ml with water. (3) Determination of chloride ion. Pipet a 10 ml aliquot of the sample solution in a 25 ml volumetric flask. Add 5 ml of the iron(III) perchlorate solution and 3 ml of the mercury(II) thiocyanate solution which is prepared by dissolving 0.463 g of mercury(II) thiocyanate in 100 ml of methanol. Dilute the mixture to 25 ml and allow to stand for 15 minutes. Transfer the solution to a 1 cm cell and measure the transmittance at 460 nm against water. The reagent blank must be run each time the iron(III) perchlorate solution has been prepared, since the water content of the solid reagent is not constant.

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In the analysis of fluorine in glass, the carbonate fusion is time-consuming when the melt is leached with water and filtered to remove the bulk of aluminum, and the result is erroneous when it is dissolved in water, neutralized to pH 6 and then the citrate buffer is added because of the coprecipitation of fluorine with aluminum hydroxide.
Four buffer solutions of citrate were examined in the ability of masking of aluminum. The more concentrated solution of citrate was found to be more satisfactory for the determination. It was unnecessary to add sodium chloride to the buffer solution. Since the TISAB (total ionic strength adjustment buffer) contains a very small amount of citrate and a large amount of sodium chloride, it is very unsatisfactory. The tolerance for aluminum increases markedly with a decrease in the concentration of fluoride ion in a buffer solution of 0.5 M citrate at pH 6. The reason is discussed theoretically. The following elements in the amounts(ppm) indicated can be tolerated; Ti, Cr, Pb, V(10), Ni, Mg(25), B(40), Cd, K, CO₃^2-(50), Fe(150), Ca(200), Si(500), and P(10000).
According to the above result, the accuracy of the fluoride determination in the presence of an excessive amount of aluminum can be confirmed by repeated measurements after each 10- or 5-fold dilution until the last two data coincide while the concentration of citrate is kept 0.5 M, as the accuracy of the potential measurement is constant over a concentration level down to 10^-5 M F^- where Nernst's equation holds.
Fuse 0.15 g of glass with 1 g of sodium hydroxide, which has been dehydrated by heating with a small amount of ethanol, in a 100 mlnickel crucible at 500°C for 20 min. Cool and dissolve in 30 ml of hot water. Adjust the pH of the solution to 2 with HCl(1 : 1) in a polyethylene beaker. Add 10 ml of a buffer solution [294 g of sodium citrate dissolved in 1 l adjusted to pH 6 with HCl(1 : 1)], and dilute to 100 ml with water. Mix a 10 ml aliquot with 10 ml of the buffer and measure the potential.
In the case of phosphate rock, shake a 0.3 g sample with 5 ml HCl(1 : 1) and 150 ml of water in a 250 ml polyethylene volumetric flask for 1 hr, dilute to the mark, and treat a 50 ml aliquot of the solution by the procedure described above. For water sample, take an aliquot containing more than 0.5 mg F^-, render alkaline with sodium hydroxide and evaporate to about 70 ml.
Results for five glasses, three phosphate rocks, and a well water agreed well with the certified values and those by other methods.

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The present report deals with the separation and determination of chlorpropamide and its decomposition products.
In the absence of decomposition products: If there is no decomposition product as demonstrated by thin-layer chromatography, chlorpropamide can be easily determined by alkalimetric titration, by the Kjeldahl method or by the ultra-violet absorptiometric method.
In the presence of decomposition products: Decomposition products are identified by thin-layer chromatography. A sample is spotted on a silica gel F 254 plate and developed with chloroform-methanol 25% ammonia (100: 25 : 1 by volume) solvent. After development, the spots are detected by iodine vapor, the ninhydrin reagent and a UV-lamp. The procedure of determination is as follows: (a) Chlorpropamide: One milliliter of sample was diluted to 200.0 ml with water. A 10 ml aliquot was taken and its pH is adjusted below 1 with diluted hydrochloric acid. The solution is extracted with isoamyl acetate and the extract is made to 100.0 ml with isoamyl acetate. Five milliliters of this solution is mixed with 2.0 ml of dinitrofluorobenzene (DNFB) and heated in a test tube with ground stopper at 140°C for 20 min. After cooling, the absorbance at 400 nm is measured against a blank solution. (b) p-Chlorobenzene sulfonamide: Five milliliters of sample is diluted to 50.0 ml with water. Ten milliliters of this solution is taken and its pH is adjusted below 1 with diluted hydrochloric acid. The solution is extracted with chloroform and the extract is made to 250.0 ml with chloroform. The absorbance at 266 nm is measured against a blank solution. The content of p-chlorobenzene sulfonamide is determined from the difference between this absorbance and the absorbance equivalent to the content of chlorpropamide as determined by the procedure described in (a). (c) n-propyl amine: Ten milliliters of sodium hydroxide solution is added to 10.0 ml of sample, the solution is extracted with isoamyl acetate, and the extract is made to 20.0 ml with isoamyl acetate. Five milliliters of this solution and 2.0 ml of DNFB are mixed and allowed to stand for 30 min at room temperature in a test tube with ground stopper, then the absorbance at 400 nm is measured against a blank solution.
When a 4.7% chlorpropamide solution (pH 9.2) is heated for 5 h at 100°C, p-chlorobenzene sulfonamide (R_f 0.75) and n-propylamine (R_f 0.40), besides chlorpropamide (R_f 0.50), were identified in the resulting solution by thin-layer chromatography. Chlorpropamide in the solution decreased by 8.9%, p-chlorobenzene sulfonamide increased by 6.7% andn -propylamine increased by 0.5%.

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An extraction-atomic absorption procedure for the microanalysis of chromium was developed with tetradecyldimethylbenzylammonium chloride(zephiramine) as an extracting reagent.
The atomic absorption measurements were made with a Perkin-Elmer atomic absorption spectrophotometer (Model 403) equipped with a multielement (chromium-cobalt-copper-iron-manganese-nickel) hollow-cathode lamp supplied by Perkin-Elmer Company. An air-acetylene flame from a 10 cm slot burner was used throughout the work.
The recommended procedures are as follows : A sample solution of chromium(VI), containing 025 μg of chromium, was taken in a 50 ml extractive tube (20 mm in inside diameter and 250 mm long) with a stopper and the pH of the solution was adjusted to 0.93.5 by adding the hydrochloric acid-acetate buffer solution. Two milliliters of 3 M potassium chloride and 2.0 ml of 2.5 × 10^-2 M zephiramine were added to the sample solution. The sample solution was diluted to 30 ml with water. The resulting aqueous solution was shaken with 10.0 ml of methyl isobutyl ketone(MIBK) for about 5 minutes. The absorbance at 3579 Å due to the chromium in the organic phase was then measured with the atomic absorption spectrophotometer against a MIBK reference.
It was found that chromium(VI) anion reacted with zephiramine and the resulting ion-pair was extracted quantitatively into MIBK in the pH range 0.9 to 3.5. Ninety-nine percent of chromium present in an aqueous solution was extracted into MIBK by one extraction. A calibration curve was linear up to 25 μg of chromium. The chromium concentration in the organic phase per 1 percent of absorbance corresponded to 0.035 μg/ml. The ion-pair(Zeph.⁺, HCrO₄^- ) extracted in MIBK was stable for 48 hours at a room temperature. The presence of Cl^-, Br ^-, NO₃^-, ClO₃^-, SO₄^2-, PO₄^3-, Mn(II), Ni(II), Zn(II), or Fe(III) caused no interference with the determination, whereas I ^-, ClO₄^-, or MnO₄^- interfered, as shown in Table II. The presence of 100 μg of chromium(III) did not interfere with the determination of chromium(VI). The total chromium in a sample can be determined by oxidizing chromium(III) to chromium(VI) with a potassium permanganate solution. The advantage of the proposed method is a rapid reactivity of chromium(VI) with zephiramine and less interference from diverse ions than other conventional extraction-atomic absorption methods with some extractants, such as ammonium pyrolidine dithiocarbamate (APDC), acetylacetone, and tri-n-octylamine etc.

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In the course of precipitation of magnesium ammonium phosphate from homogeneous solution by means of hydrolysis of p-nitrophenylphosphate with an alkaline phosphatase in the presence of cobalt, the behavior of cobalt and the conditions for the quantitative precipitation of magnesium in the presence of cobalt were studied.
Precipitates of magnesium ammonium phosphate are contaminated with a considerable amount of cobalt under such conditions that cobalt does not precipitate in the absence of magnesium. When a certain amounts of precipitates of magnesium ammonium phosphate, which was prepared separately, was added to a solution containing cobalt (II) ions, phosphate ions, and ammonia-ammonium chloride, the concentration of cobalt in the mother liquid was decreased after two hours and cobalt phosphates were precipitated on the surface of the magnesium ammonium phosphates. This fact suggests that precipitation of cobalt phosphates is induced by the magnesium salt.
When magnesium ammonium phosphates were precipitated from homogeneous solution in the presence of cobalt, two types of contamination with cobalt were observed; contamination due to inclusion of cobalt ion in the lattice of magnesium ammonium phosphate and that due to secondary precipitation of cobalt phosphate on the surface of the magnesium precipitate. The contamination of the first type is not removed easily by digestion of the precipitate in concentrated ammonia-ammonium chloride buffer solution, while the contamination of the second type can be almost removed.
The effects of EDTA and potassium cyanide as masking reagent were studied; but both agents prevented quantitative precipitation of the magnesium ammonium phosphate and inhibited the enzyme action.
Addition of concentrated ammonia-ammonium chloride buffer solution is very effective to decrease the contamination. Although it inhibits the enzyme action slightly, quantitative precipitation of magnesium ammonium phosphate can be satisfactorily achieved by using a suitable excess amount of the enzyme.
The following procedure is recommended for determining 10 mg of magnesium in the presence of less than 10 mg of cobalt. Add 20 ml of ammonia-ammonium chloride buffer solution (pH 9.5), 3 ml of 0.4 M disodium p-nitrophenylphosphate solution, and 6 ml of 0.1 % alkaline phosphatase solution to the sample solution, and dilute to 50 ml with water. Keep the solution at 30°C for more than 8 hours. Filter the precipitate, dry it at 50°C, and weigh as MgNH₄- PO₄·6H₂O. The relative error is less than 0.7%.

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Although polystyrene porous polymer resin (Amberlite XAD-2) did not adhere to the glass surface, a thinlayer plate of this resin could be prepared by adding 10% polyvinyl alcohol-1500 as the binder. The plate was useful for reversed phase thin-layer chromatography (TLC) because of its non-polarity. Several compounds i.e., fat soluble vitamins (ethanol or n-hexane), flavonoids (70% methanol), fatty acids (methanol/0.01 M NaOH = 99 : 1) and malonates (mixture of methanol or ethanol and water), were separated using solvents indicated in the respective parentheses. R_f values of the malonates varied with the alcohol concentration in the developping solvents. When the R_f values were plotted against V_R values which was determined by high speed liquid chromatography using the same solvents, the plots approximated to the curve drawn by an equation derived from the partition theory. Consequently, V_R value could be predicted by calculation from R_fvalue on TLC prior to high speed liquid chromatography.

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The solvent extraction of cobalt(II) and nickel(II) with 1, 1, 1-trifluoro-4- (2-thienyl) -4-mercapto-3-buten-2-one (STTA) in cyclohexane has been investigated, and on this basis a new method for mutual separation and spectrophotometric determination of the metals by back-extraction has been developed. When a sample solution the pH of which had been adjusted to 5.56.0 was shaken with a 10^-3M STTA-organic solution, the extraction of cobalt(II) and nickel(II) proceeded rapidly and quantitatively. Nickel(II), however, could be stripped out of the organic phase by shaking with an aqueous solution of pH 1.5, while cobalt remained in the organic phase. After the phases separated, the organic phase was reserved for cobalt, while the aqueous phase which contained nickel was adjusted again to pH 5.56.0 and shaken with a 10^-3M STTA-organic solution. Then, two organic phases, the former containing Co(STTA)₃, and the latter Ni(STTA)₂ was respectively shaken with an aqueous buffer solution of pH 9.510.5 to remove most of the excess of STTA from the organic phase. Cobalt and nickel up to 10^-6M in the final organic phases could be determined individually by measuring the absorbance at 370 nm or 450 nm against the reagent blank. The molar absorption coefficients expressed in cm² l mol^-1 of the chelate in cyclohexane were found to be 3.5×10⁴ (370 nm) and 1.0×10⁴ (450 nm) for Ni(STTA)₂, 9.0×10⁴ (370 nm) and 1.3×10⁴ (450 nm) for Co(STTA)₃, respectively. Anions, such as oxalate, citrate, and hexacyanoferrate(II), as well as EDTA interfered with this extration. Nickel contents as small as 10^-6M in samples of cobalt chloride hexahydrate of analytical reagent grade and in pure cobalt metal could be determined by the present method.

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The rapid determination of sodium hydroxylalkanesulfonate in α-olefin sulfonate (AOS) was investigated by means of NMR spectroscopy; this led to a convenient method for routine analysis of AOS.
From comparison of NMR spectrum of sodium C₁₆-3-hydroxylalkanesulfonate with that of sodium C₁₁-2-alkenesulfonate, any specific signal easily accessible for the determination could not be found. Therefore, in order to eliminate the influence of double bond, the hydrogenation of sodium C₁₁-2-alkenesulfonate was carried out with the ordinary manner using Pd/C catalyst. NMR spectrum of the hydrogenated product turned out to have a very simple pattern(See Fig. 2) in which only one signal based on CH₂-SO₃ proton appeared in the 2.44.0 ppm region. Authors found that sodium hydroxylalkanesulfonate in AOS was able to be determined by using the signals of CH₂-SO₃ at 2.73.1 ppm and CH-O at 3.43.7 ppm.
By using this method, sodium C₁₆-3-hydroxylalkanesulfonate in mixtures of sodium C₁₆-3-hydroxylalkanesulfonate and sodium C₁₁-2-alkenesulfonate was determined accurately and rapidly over a wide range (6.390.2 mol%).

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Phosphorus in organic compounds was determined by atomic absorption spectrophotometry. At this moment, it is difficult to determine phosphorus directly by atomic absorption spectrophotometry. However, molybdophosphoric acid produced by the reaction of phosphoric acid with ammonium molybdate is extractable with organic solvents and hence phosphorus is capable to be determined indirectly by the measurement of the molybdenum extracted by atomic absorption spectrophotometry. Although nitrous oxideair fuels have usually been employed for the determination of molybdenum, this time an attempt was made by using an acetylene-air fuel, instead of nitrous oxideair.
Measurements were made with a Hitachi Model 207 atomic absorption spectrophotometer and the working conditions are as follows: lamp current 10 mA; acetylene flow rate 4.5l/min; air flow rate 13.0l/min; slit width 0.18mm and wavelength of Mo is 3133 Å.
Procedures : To 5ml of a standard phosphorous solution (5μg/ml), 5ml of 60% perchloric acid was added and the mixture was diluted to 40ml with water. To this 3ml of 10% ammonium molybdate was added and molybdophosphoric acid produced was extracted with MIBK, and the extract was washed twice with water. The MIBK was used for the measurement. According to this method, a calibration curve of phosphorus shows a linear relation up to the concentration of 2.5μg/ml. Recovery was 101.9% by the back extraction with 3 M ammonia water.
Under the conditions, an ionic sample such as histamine diphosphate was dissolved in water and treated by the usual procedure, while such non-ionic samples as triphenylphosphine and pyridoxal phosphate were decomposed by boiling with concentrated sulfuric acid and concentrated nitric acid and then they are treated similarly to the ionic sample. The standard deviation was 0.200.28.

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