Morin reagent

F1uorescence detection after derivitization with Morin reagent... 

Morin reagent is also used for the detection of peptides. The developed plates are dried and sprayed with 0.05% morin (3,5,7,2, 4 -pentahydroxyflavone) solution in methanol and activated for 2 min at 100°C. In this case, the peptides produce yellowish-green fluorescent spots on a green fluorescent background or dark absorption spots under UV hght. The detection limit is just about 2 p,g/spot. Detection of P-labelled opioid peptides is done by autoradiography. 

Color reactions are more or less clearly defined reactions of the substances with suitable reagents. Substance-specific reactions are not usually available, e. g. many compounds with aromatic skeletons give both a positive Vitali-Morin reaction [1 -4] and a positive Marquis reaction [4]. Again, numerous aldehydes react with electron-rich compounds in acidic medium to yield colored substances (cf. Chapters 2 and 3.1). 

Monoterpenes lb 448 Monoterpene glucosides la 327,328 Monoterpene hydrocarbons la 76 Monoterpene ketones lb 252-254 Monuron lb 252,418 Morazone la 45 Morgan-Elson reagent lb 63 Morin la 44,91... 

Analysis. Colorimetric methods provide for the determination of Al down to 10 ppb. AAS will analyze for Al down to 50 ppb, ETAAS to 10 ppb, and ICPAES to 1 ppb. ICPMS improves upon this by going down to 0.1 ppb. Alizarin is a reagent which provides for a spot test of Al dovm to 20 ppm. Al+ can also be detected in a spot test by morin in methanol down to 10 ppm. 

The flavone morin (700) (Natural Yellow C.I. 75660) dyes wool yellow, the actual shade being determined by the mordant which is used. It has also been mentioned as a spot test reagent for salts of aluminum, beryllium, zinc and other metals (B-54MI22401). 

Table 6 merely lists reagents such as xylenol orange (44) and arsenazo(III) (45) which are often used absorptiometrically, and morin (46) used also in fluorimetric procedures, together with other reagents for the commoner metals. It would be pointless to give practical details of procedures which can be found in standard text books3-7,22,30,33 or specialist publications.76,77 IUPAC have... 

Other organic reagents recommended for determining chromium include phenylfluorone [49] and o-nitrophenylfluorone (in the presence of CTA) (e = 1.1-10 at 582 nm) [50], Methylene Blue (e = 8.3-10" ) [51], Pyrogallol Red [52], morin [53], and 2,2 -diquinoxalyl [54]. Chromium was also determined by a sensitive method based on the ion-associate of Cr(VI) with Rhodamine 6G in aqueous solution containing poly(vinyl alcohol) [55], and after extraction into toluene [56]. 

Many other reagents have been used for determining iron, e.g., sulphosalieylic acid [106-109], ferron (7-iodo-8-hydroxyquinoline-5-sulphonic acid) (e = 4.0-10 at 610 nm) [110], Tiron [111,115], HTTA [116,117], pyrocatechol [118], phenylfluorone (in presence of Triton X-100 [119], morin (in the presence of a surfactant e = 6.3-10 ) [120-122], Alizarin S (extraction with Aliquat 336 in CHCI3] [123], Purpurin [124,125], salicylates[126,127], 2,2 -diquinoxalyl [128], sulphanilic acid in the presence of a surfactant [129], haematoxylin [130], and hydroxamic acid derivatives [13,14,131,132]. 

Other organic reagents recommended for determination of Mo include Alizarin Complexone [103], l-nitroso-2-naphthol [104], morin [105], rutin [106], quercetin [107], 1,5-diphenylcarbazone [108], quinalizarin in the presence of surfactant [109], tiron [12,31,39], and 2,2 -biquinoxalyl [110]. The FIA technique has been applied in the determination of Mo with the use of carminic acid [111]. 

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],... 

Flavone reagents quercetin [71,72] and morin (formulae 57.4 and 57.3) [73] have been recommended for determining tin. In the presence of antipyrine, the Sn(IV) compounds can be extracted into chloroform [73]. 

Fiber-optic sensors, particularly fluorescent sensors, have become the object of considerable interest among researchers. The action of most fluorescent sensors is based on the change in the fluorescence properties of organic reagents immobilized on a solid matrix upon contact with solutions of metals in a continuous system. Zelters et al. [187] studied the immobilization and complex formation of immobilized Morin with zirconium and tin in order to develop a procedure for sorption fluorimetric determination of these elements. The selection of polyoxiflavones for immobilization was determined as a valuable analytical procedure. 

Fig. 2. Flow diagram of the FI A system used. R reagent carrier solution (1x10 M Morin in ethanol water (4 96 v/ v) in 0.1 M HAc/ Ac buffer (pH 4.50)), P, Peristaltic pump, S Rheodyne sample injection valve, RC reaction coil (50 cm long, 0.5 mm i.d), D spectrophotometric detector Xmax = 415 nm), W waste, C computer, P printer.

A Fe(II)-Morin (1 2) complex was indicated by both methods. The reaction was very fast. Metal ions react with Morin in aqueous medium in the range pH 2.0-7.0 forming coloured complexes with different stoichiometry. Absorption spectra s those correspond to solutions of 5xlCf5 M of iron (ll)-Morin complex was measured against a reagent blank and the average molar absorption coefficient of 6.82 x ICH L moH cirri are shown in Fig. 3. 

The pH of the reagent carrier was however adjusted to 4.5 to obtain maximum peak height and minimum iron (III) interference in the analysis. In order to proceed with the final system design, the effect of sample volume, mixing coil length and flow-rate were studied using Morin at fixed concentration of 2.5xlCH M and pH 4.5. 

Morin (2, 3,4, 5,7-pentahydroxyflavone). Formula see flavones. C15H10O7, Mr 302.24, light yellow needles, mp. 303-304°C. M. occurs in various woods, e.g. in Moms alba (mulberry tree, Moraceae). M. was first isolated in 1830 and is used as a reagent in spot reactions to detect Al, Be, Zn, Ga, In, and Sc salts, in photometric analysis and as a textile dye. It shows anti-HIV activity... 

Numerous techniques have been described to evaluate total tin on ashed or wet mineralized biological, food, or environmental media by colorimetric determination of tin(IV) with phenyl-fluorone [51-53], catechol violet [54-59], salicylaminothiophenol [60], hematoxylin [61], quercetin [62,63], dithizone [64], or dichloro-8-quinolinol [65]. In general, these analytical reagents are nonspecific and best suited to samples where tin values in materials are not lower than about 0.2 ppm. A better sensitivity may be obtained with fluorimetric methods using morin [66,67] or diacetylmonoxime nicotinylhydrazone [68]. 

Sensors for metal ions are based on the use of non-fluorescent or weakly fluorescent reagents which form highly fluorescent complexes with the metal ions of interest. For example, the reagent morin (3, 5, 7, 2 4 -pentahydroxyflavone), immobilized on cellulose by covalent bonding, forms intense fluorescent complexes with aluminium (64) and beryllium (65) which are used to sense these ions. The detection limits for these transducers are reported to be 27 ppb for aluminium and 9 ppb for beryllium. 

Spray reagent 1% morin solution in acetic acid. Yields intensive... 

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