Phenylfluorone complexes

At wavelengths >500 nm the interference from the absorption of the reagent is slight. The molar absorptivity of the solution of the Ge-phenylfluorone complex, under the conditions given in the procedure below, is 5.3-10 at 510 nm (a = 0.73). 

Tin(IV) reacts with phenylfluorone (formula 22.1) in aeidic medium to form a sparingly soluble complex. At low coneentrations of tin, this complex oecurs in solution as a sol suitable for the spectrophotometric determination of tin [11,24,25]. The reagent solution is yellow, whereas the pseudo-solution of the Sn-phenylfluorone complex is orange-red. 

Germanium solutions in the presence of phenylfluorone (1) and lauryldimethylam-monium bromide yield coloured compounds, Zmax 508 nm, el.60 x 105. This allows germanium determination at concentrations of 8-80 Xg/L. Only Sb, Sn, Cr(VI) and Mo interfere with the analysis17. Precipition and filtration of the Ge(IV)-l complex formed in... 

With metal ions, some organic reagents form coloured compounds that are sparingly soluble both in water and in organic solvents. They are either polynuclear complexes, such as formed by phenylfluoron with Sn(IV) or with Ge(IV), or adsorption-type compounds such as those formed by titanium yellow with Mg. In such cases, the absorbance is measured for suspensions of coloured pseudo-solutions stabilized with protective colloids [e.g., gum arabic, gelatine, poly(vinyl alcohol)]. 

Many other organic reagents have been used to determine Co, including phenylfluorone (in the presence of CP, e = 1.16-10 at 620 nm) [84,85], and ferrozine [86,87]. A very sensitive method has been based on the complex of Co with a,p,y,5-tetrakis(4-sulphonyl)porphyrin (Co replaces Cd in the complex) (e = 2.4-10 at 432 nm) [88,89]. ]. Less sensitive methods for Co utilize EDTA, DCTA, EGTA and NTA ( = 200-300 nm) [90]. 

Phenylfluorone also forms coloured complexes with many metals, e.g., Sn, Sb, Ti, Fe(III), Nb, and Ta. Low concentrations of arsenic, silicon, and fluoride do not interfere in the formation of the germanium complex. Citric and oxalic acids are used to mask Mo, V, Sn, and Ti [19,20]. Preliminary separation of germanium as GeCU by extraction or distillation renders the phenylfluorone method specific for germanium. 

When the colloidal solution of germanium phenylfluoronate is shaken with CCU, the precipitate agglomerates at the interface. After removal of nearly all the CCLt and the aqueous solution (containing the excess of phenylfluorone), the precipitate is dissolved in acetone and the absorbance measured [21]. High sensitivity (e= 1.2-10 at 495 nm) is obtained, if phenylfluorone is added to a chloroform extract of Ge complex with N-p-chlorophenyl-2-furohydroxamic acid [8]. A DMF solution of phenylfluorone was also added to a toluene extract of GeCL (e = 7.1 10 at 525 nm [3].An aqueous solution of Ge was also... 

Among 2,3,7-trihydroxy-6-fluorones, the best results in the determination of Nb were obtained with phenylfluorone and o-nitrophenylfluorone (e = 1.3-10 - 1.7-10 ) [69-71]. A very sensitive method has been based on a mixed complex of Nb with o-nitrophenylfluorone and DAM (e = 1.9-10 ) [72]. Even higher sensitivity (e = 2.1 -10 ) has been obtained with the... 

Numerous indirect amplification methods have been devised for the determination of phosphate. The molybdenum in an extract of molybdophosphoric acid (Mo P = 12 1) has been determined with thiocyanate [63], phenylfluorone [64], dithiol (e = 1.7-10 ), Sulphonitrophenol S (e = 4.610 ) [65], or 2,2 -diquinoxalyl [66]. The indirect method that involves the Fe(ll)-ferrozine complex [67] is unusually sensitive (e = 9.7-10 ). In another method involving the complex of Ce(III) and Arsenazo III, the phosphate gives a sparingly soluble CeP04 and liberates an equivalent quantity of Arsenazo III [68]. 

There exist several indirect methods for the spectrophotometric determination of silicon. After extraction of molybdosilicic acid, the Mo has been determined with phenylfluorone [45], or 2-amino-4-chlorobenzenethiol (e = 2.0-10 ) [46]. When silicic acid is added to a solution which contains hydrofluorotitanic acid and H2O2, a yellow titanium peroxide complex is formed. Chloranilic acid has also been used for determination of silicon [47],... 

Other organic spectrophotometric reagents, recommended for determination of thorium are Bromopyrogallol Red [85], morin (e = 3.3-10 at 422 nm), quercetin [86,87], phenylfluorone [87], and 8-hydroxyquinoline [88], The anionic complex of 5,7-dibromo-oxine with Th forms an ion-associate with Rhodamine B which can be extracted into benzene (e = 8.8-10 at 552 nm) [89],... 

Methods with the use of fluorones also have high sensitivity. Among the reagents proposed are phenylfluorone [63], 3 -pyridylfluorone (e = 1.25-10 ) [64], and salicylfluorone (in the presence of CTA, e = 4.8-10 ) [65]. The V complex with salicylfluorone has been extracted into a mixture of n-butanol with CHCI3 (e = 1.2-10 ) [66]. 

FIA system using thiocyanate and malachite green in the presence of surfactants CPC and Triton X-100 was applied to determine Zn (and Co) in beverages, biological, environmental and pharmaceutical samples [7]. Detection limit of 15 ppb was obtained. Phenylfluorone in the presence of Triton X-100 and cetylpyridinium chloride was used for the determination of Zn in insulin (A. = 573 nm, e = 1.09T0 1 mol cm ) [8]. Zinc in industrial effluents was determined by the use of the complex with PAR [9]. Simultaneous... 

The photometric determination of Ge with phenylfluorone was, and still is, one procedure for the analysis of this element in inorganic and organic samples. The detection limit can be improved when the formed Ge complex is transferred into benzyl alcohol by extraction before measuring. The detection limit is then about 0.01 pg Ge mL (Henze 1986). 

This test can be used for the detection of Ge in paper chromatography. The complex of germanium and phenylfluorone is insoluble in organic solvents and accumulates at the interface between water and CCI4. This allows 0.02 y Ge to be detected in 1 ml of test solution. ... 

Diffuse reflection spectrometry with 8-hydroxyquinoline-5-sulfonic acid and phenylfluorone after sorbing on a disk of an anion exchange fibrous material Spec determination of the binary complex based on the extraction tetraphenylphosphonium or tetraphenylarsonium chloride Spec X = 490 nm of chelate (pH = 5.0)... 

In, Th, Zr) with some chelating reagents (e.g. chromazurol S, bromopyrogallol red, phenylfluorone) forms ternary complexes. 

C23H42CIN M 368.044 Used as 0.2% aq. soln. to increase sensitivity in photometric detn. of metals (e.g. Al, Be, Ga, Th, with some chelating reagents (e.g. chromazurol S, phenylfluorone) (forms ternary complexes). Commercially available as dihydrate. Colourless or pale yellow powder. Sol. H2O, EtOH, Me2CO. Mp 63-65° (dihydrate). 

Phenylfluorones are a variety of chelating xanthene molecules which form sparingly soluble coloured complexes with certain inorganic species. Phenyl-fluorone (2,6,7-Trihydroxy-9-phenyl-3H-xanthen-3-one) itself, for example, forms a reddish suspension with Ge(/V0, Ga(//7), Sn(iy), SB(//7) and other species. The coloured suspensions can be stabilized with a protective polymer such as poly(vinyl alcohol) for spectrophotometric measurement. 

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