Fluorescent derivatives ether

The fish tissue sample containing AMO residues was homogenized with phosphate buffer (pH 4.5), followed by protein precipitation with TCA and SPE on a C18 cartridge. Trace amounts of nonpolar interfering substances present in the SPE eluate were removed by LLE using ether. The final extract was reacted with formaldehyde and TCA at 100°C for 30 min. A fluorescent derivative was extracted with ether three times, and the extracts were combined, evaporated, and reconstituted in the mobile phase. No interfering peaks from the control fish extract were observed. A proposed chemical structure of the fluorescent derivative was reported and confirmed by both MS and NMR experiments (73). 

Used for the precolumn preparation of fluorescent derivatives of carboxylic acids using acetone as solvent and with crown ether and alkali as catalysts Reference 5... 

Antibiotics The AOAC has listed methods for sulfamethazine residues in swine tissues with determination either by GC-MS or GC-ECD of methylated derivatives and for sulfamethazine (and for the class of sulfonamides) in milk with determination by HPLC-UV. There is an AOAC method for the class of sulfonamide antimicrobials in animal tissues using solvent extraction and liquid partitioning with determination by TLC and fluorimetric scanning. For analysis of tetracyclines, AOAC describes methods based on buffer extraction from tissue samples and SPE (Cis) cleanup, or metal chelate affinity binding from milk samples, with determination in both cases by HPLC-UV. USDA/FSIS methods include (1) a method (similar to the AOAC GC-MS method for sulfamethazine) for confirmation of sulfonamide residues in edible tissues using solvent extraction and multiple liquid partitioning with determination of the methylated derivatives by GC-MS (2) methods for determination and confirmation of chloramphenicol in muscle by solvent extraction, liquid partitioning, and determination of the trimethylsilane (TMS) derivative by GC-ECD and GC-MS, respectively and (3) a method for determination of the beta-lactam antibiotic amoxicillin by aqueous extraction, cleanup by tricarboxylic acid precipitation, and ether extraction and formation of a fluorescent derivative for determination by LC. 

Fluorescent derivatives of prostaglandins were recently separated and determined by OPLC on HPTLC plates using ethyl acetate-diethyl ether-benzene-dioxane-hexane (45 12 5 8 30, v/v) mixture as eluent (88). The linearity of calibration graphs were good in the range 1-100 ng. This range was satisfactory for the determination because the detection limit of analytes were 10-40 pg. 

The new fluorescent poly(aryl ethers) derived from nonfluorescent monomers have gained significant attention from polymer scientists [20]. These polymers are prepared by the polymerization of phenolphthalein and its derivatives with activated aromatic difluorides. 

M -Dialkyldiazacrown ethers and their precursors fcis(alkylamino) derivatives of tri- and tetraethylene glycols were prepared <96CCCC622>. New hydroxy-bearing dibenzo-azocrown ethers have been conveniently prepared utilizing l,3-Ws(2-formylphenoxy)-2-propanol and a diamine, followed by reduction of the intermediate diimine <96P1197>. Fluorescent photoinduced electron transfer sensor 5 with monoaza-18-crown-6 and guanidinium receptor units demonstrated a fluorescence with T -aminobutyric acid in a mixed... 

Chlorophylls and their derivatives fluoresce independently from one another and their concentrations can be calculated by equations based on the total fluorescence — the sum of individual fluorescences when together or in mixtures. Equations for 80% acetone, diethyl ether, DMF, methanol and ethanol can be found in literature. 

Crowns with Polymethines Dyes. The ready synthesis, see Figure 3.18, of crown ethers attached to polymethines or hemicyanines has made these compounds a fertile area of research and application in metal ion sensing. AU of these polymethine derivatives are cation responsive e.g. (3.84b) forms complexes with Na, Mg, Ca, Sr and Ba with an increase in fluorescence intensity. 

A more comprehensive approach was reported in 1975 by Brabander and Verbeke (612). In this method, tissue samples were extracted with methanol and the acidified extract defatted with petroleum ether to be loaded onto a Dowex 50W-X8 anion-exchange resin. Following elution with aqueous methanol, the concentrated buffered extract was further defatted with diethyl ether. The sample was derivatized with 7-chloro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-Cl) to be further spotted on a silica high-performance thin-layer chromatographic plate developed in two dimensions using chloroform/ethanol and chloroform/propionic acid consecutively as eluents. Detection of the propylthiouracil, phenylthiouracil, and tapazole residues was carried out on the basis of the fluorescence induction of the NBD derivatives of the drugs with an alkaline cysteine solution. 

Fluoro-7-nitrobenzofurazan (4-fluoro-7-nitrobenzo-2-oxa-l,3-diazole) [29270-56-2] M 183.1, m 52.5-53.5°, 53-56°, 53.5-54.5°. Purified by repeated recrystn from pet ether (b 40-60°). On treatment with MeONa in MeOH it gave 4-methoxy-7-nitrobenzo-2-oxa-l,3-diazole m 115-116°. [Nunno et al. JCS (C) 1433 1970]. It is a very good fluorophore for amino acids [Imai and Watanabe Analyt Chim Acta 130 377 7987], as it reacts with primary and secondary amines to form fluorescent adducts with 470nm and Agn, 530nm. It gives a glycine derivative with m 185-187° [Miyano et al. Analyt Chim Acta 170 81 7985]. 

The excited state properties of bis-a-9-anthrylmethyl ethers 23 closely resemble those of l,3-di-9-anthrylpropane derivatives. The photoexcited parent compound 23a deactivates by fluorescence (0 = 0.03) from the locally excited state only, and it isomerizes by intramolecular 4ji+4ji cycloaddition with a quantum yield of 0.32 [66]. By contrast, excimer emission (see Table 4) does characterize the excited state properties of the 10,10 -diphenyl derivative 23b, which does not undergo intramolecular cycloaddition for steric reasons [66,67]. 

Another method of preparation is as follows 1 33 parts of fluorescein are dissolved in 5 parts of ether and treated with 25 parts of selenium chloride in the same solvent. A yellowish-red precipitate separates, and after long stirring at the ordinary temperature the ether is distilled off. The residue is stirred with water, the mixture filtered and the residue now dissolved in sodium hydroxide. After further filtration the filtrate is treated with hydrochloric acid, which precipitates seleno-fluorescei n. Further purification is effected by solution in alkali and reprecipitation. A reddish-brown powder is obtained, soluble with fluorescence in alcohol, but insoluble in water. In concentrated sulphuric acid it dissolves to give an orange solution. Its alkali salts are very soluble in wrater, giving red solutions. This process may also be applied to phthalins, which are obtained by the reduction of phthaleins and their halogen derivatives. If the selenium chloride is replaced by the oxychloride similar products are obtained.2 In place of the phthalins specified in the patents quoted, their O-acetyl compounds or O-acetyl compounds of the phthaleins may be used in indifferent solvents. The products are different from those obtained by the action of selenium on fluoresceins in aqueous alkali solutions.3... 

Some other 3-thienyl ether derivatives have been prepared. Poly[3-oligo(oxyethylene)-4-methyltiophene] showed an absorption peak at 550 nm (95JCS(CC)2293). On the other hand, poly[3-(N-succinimido(tetra-ethoxy)oxy)-4-methylthiophene] was prepared and it is able to react with amines to give the corresponding carbamate with a 15-crown-5 attached substructure. This polymer showed absorption at 429 nm and fluorescence at 543 nm (04T11169). 

A. P. de Silva Fluorescent sensing of alkali metal ions by crown ether derivatives... 

---