Spectrophotometric determination of osmium (VIII) with promazine hydrochloride

Promazine hydrochloride is proposed as a new reagent for the spectrophotometric determination of osmium (VIII). The reagent forms orange oxidation product with osmium tetroxide at room temperature in acidic media. The effects of acid concentration, time, temperature, and foreign ions are reported. Beer's law is obeyed in the osmium concentration range 1–10 μg/ml.     

Spectrophotometric determination of palladium(II) with 5 (p-dimethylaminobenzylidene)rhodanine

A sensitive spectrophotometric method has been developed for tlie deternination (of pallaudium, busing 5(p-dimethylaminobenxylidene)rhodanine reagent in formic, hydrochloric, or propionic acid solution. The systems conform to Beer's law. The specific absorptivity is in the range 0.38 to 0.40 per p.p.m.-cm in the different solvents. The optimum range for 1.00-cm optical path is about 0.4 to 2.5 p.p.m. of palladium. At higher concentrations of palladium a violet-red precipitate forms within a few minutes. In propionic acid solution maximum color is attained at room temperature in 10 to 15 min, and is stable for more than two hours. The system is somewhat sensitive to hydrogen ion concentration; maximum absorbance and stability are attained at 0.01 N hydrochloric acid in tlie final .solution, Platinum (IV), ruthenium (III), iron(lll), iron (III), chromium (VI), and copper(ll) interfere if present in amounts several times greater than the amount of palladium ; gold(ll1) interferes very exensively. Tlie mole ratio method, the continuous variations method, and the slope ratio method all show the mple ratio of DMABR to palladium to be 2 : 1 in the color-forming reaction.     

Spectrophotometric determination of titanium(IV) with 1-phenyl-2-methyl-3-hydroxy-4-pyridone

Analytical and Bioanalytical Chemistry -     

Spectrophotometric determination of osmium using acenaphthenequinonemonoxime (AQM)

A water-soluble dark-brown complex formed by osmium with acenaphthenequinonemonoxime exhibits an absorption maximum at 430 nm. The composition of the complex comes out to 1:2 (metal:ligand) as revealed by Job's method of continuous variations, logarithmic method, and Gerade method of Asmus. The pH range for complete formation of the complex is 6.5–8.5. Its sensitvitiy has been found to be 0.0323 μg/cm². The effect of diverse ions has also been investigated.     

Spectrophotometric determination of osmium with quinisatin oxime

A spectrophotometric determination of osmium has been developed, based on the purple color (absorption maximum at 515 mμ) formed by reaction of osmium with quinisatin oxime in buffered solution of dimethyl formamide and methanol. The absorbances are reproducible, and the system conforms to Beer's law. The method compares favorably in sensitivity with existing methods for osmium. The optimum concentration range (for 1 cm optical path) is about 2 to 10 p.p.m. of osmium. Although the maximum color develops slowly, it is stable for 7 days or longer. Several elements, notably iron, cobalt, and ruthenium, interfere, so that separation, is necessary. A reaction ratio of 1:2 for osmium and quinisatin oxime was clearly indicated; some evidence was also obtained for the presence of higher complexes.     

Spectrophotometric determination of osmium with 1,5-diphenylcarbazide

The formation of the bluish violet osmium-diphenylcarbazide complex in weakly acidic solution is utilized for the determination of osmium by spectrophotometry. When measurements are made at 560 nm, after extraction of the complex into isobutyl methyl ketone, Beer's law is obeyed up to 150 mug of osmium. Relatively few ions interfere, and these can be masked with EDTA and fluoride.     

Spectrophotometric determination of osmium with ethylisobutrazine hydrochloride

The sheath flow cuvette is used for refractive index determinations of neat solutions within picoliter probe volumes. In this detector, a sample stream is injected as a narrow stream into the center of a flowing sheath stream under laminar flow conditions. The sample stream retains its identity as a thin cylinder through the center of a 250-m square flow chamber. The propagation properties of a focused helium-neon laser are perturbed by interaction with the sample stream. Detection limits of RI=3×10^–6 were obtained within a 20 micrometer radius sample stream, corresponding to about a 400 picoliter probe volume. For analyte with refractive index significantly different than the solvent, detection limits are possible which correspond to a few picograms of analyte within the probe volume.     

Spectrophotometric determination of iron with bis(2-hydroxymethyl-5-hydroxy-4-pyrone-6)ketone

Summary A method has been developed for the direct spectrophotometric determination of iron by using the reddish-orange coloured complex formed in the interaction of iron with bis(2-hydroxymethyl-5-hydroxy-4-pyrone-6)ketone. The red colour follows Beer's Law and is stable. The method is sensitive, reproducible and accurate. Of the several anions and cations studied, only a few interfered seriously in the determination of iron. However, the ones that do interfere seriously can be separated by conventional methods of separation.

---

Zusammenfassung Zur direkten spektrophotometrischen Eisenbestimmung wird der rötlich-orange gefärbte Komplex benutzt, der sich aus Eisen und Bis(2-hydroxymethyl-5-hydroxy-4-pyron-6)keton bildet. Die Färbung befolgt das Beersche Gesetz und ist beständig. Das Verfahren ist empfindlich und liefert genaue und reproduzierbare Ergebnisse. Die wenigen Ionen, die erhebliche Störungen verursachen, können zuvor nach üblichen Verfahren abgetrennt werden.

     

Spectrophotometric determination of iron with 2-hydroxy-3-napthoic acid

2-Hydroxy-3-napthoic acid is presented as a new, highly sensitive and selective reagent for its colour reaction with ferric ion. The sensitivity of the reaction is 0.025 μg/cm² (SANDELL). The blue-coloured complex is maximally absorbed at 590 mμ and obeys Beer's law up to 24 p.p.m. of iron. The optimum range of concentration is from 4 to 20 p.p.m. of iron, where the percent relative analysis error per 1% absolute photometric error is 2.9. The composition of the complex, as evaluated by JOB's method and as verified by the Molar and Slope ratio methods, shows that in solution, the complex contains the iron and the reagent in a ratio of l : 1. The empirical formula of the complex is suggested to be [Fe(C₁₁H₇O₃)]⁺². The molar extinction coefficient is 2212 and the instability constant of the complex is about 4.29 ? 10^-4. Coloured ions or those ions that give coloured products are tolerated to a limited extent during the determination of iron.