Phosphate fluorometric detection

Kitada et al. (5,41) used a rapid method for TBZ and BP in citrus fruits. The crops were extracted with ethyl acetate and separated on a reverse-phase C8 column with UV and fluorometric detection, respectively. Methanol phosphate buffer mixture at a flow rate of 1.0 ml/min gave satisfactory results as the mobile phase. Recoveries of postharvest residue were greater than 93%. Carbendazim and thiophanate-methyl were determined in chicory, beans, lettuce, strawberries, and tomatoes (5,42). After extraction with methanol, the extract was cleaned up on a Sep-Pak C g cartridge. The rapid method gives recoveries of between 90 and 100%. 

The US Army Medical Research Institute of Chemical Defence employs an automated microdistillation assay for cyanide in blood, using fluorometric detection (67). For assaying free CN , plasma is mixed with and dialyzed against pH 7.4 phosphate buffer. For an assay of total blood cyanide, blood is mixed with saline containing Triton X (which hemolyzes the red cells), treated with 0.5 % sulfuric acid and dialyzed against 0.25 % sulfuric acid. Cyanide is... 

Yu et al. (1986) achieved a detection limit of 3.8 pg for the TBA-MDA adduct using fluorometric detection (532 nm excitation 550 nm emission). The adduct was separated on a Zorbax Cl8, 3 //m column (0.63 x 15 cm) or an Altex ODS, 5 /rm analytical column (0.46x25 cm) the columns were eluted with 0.01-0.025 M phosphate buffer (pH 6.5)/methanol (60 40, v/v) at a flow rate of 1.0 ml/min. A presaturation column packed with Corasil silica (35-50 yum) was placed between the pump and the column. Reducing the pH of the mobile phase had little effect on retention time but symmetry and band broadening were worse at more acidic pH probably because the thionyl group of the TBA adduct is increasingly ionized at pH 6.5 and is less attracted to similarly charged residual silanols on the ODS columns. 

The quinoxalone derivatives of pyruvate and 2-ketobutyrate were separated on a /iBondapak Qg reversed-phase column (3.9 mm x 300 mm). The mobile phase was a mixture of acetonitrile, methanol, and 40 mM phosphate buffer (pH 7) (5 8 12, v/v/v) run at a flow rate of 1 mL/min. Detection could be carried out spectrophotometrically at 254 nm, or fluorometrically with excitation and emission wavelengths of 340 and 389 nm, respectively. 

Semi-quantitative determinations can be made using the visual comparison method [8]. Waldi [143] has worked out a quantitative procedure for Bg and Bg-S -phosphate as sodium salt the spots or zones, separated on silica gel H, were detected in the quartz lamp radiation, scraped off, eluted with 0.1 N hydrochloric acid and determined colori-metrically or fluorometrically against a reference solution [130]. 

In our HPLC system, thiamine compounds were converted to thiochromes by alkaline BrCN oxidation prior to separation. An ODS column was used as the stationary phase and 2.5% /V,/V-dimethylformamide (DMF)-25 mM potassium phosphate buffer (pH 8.4) as the mobile phase. The thiochromes were detected fluorometrically. After completion of ThcMP elution, the mobile phase was... 

A reversed-phase HPLC of thiamine phosphates followed by postcolumn fluorogenic oxidation was described by Kimura et al. (33). A pBondapak Cig column was used with a mobile phase of a 0.2 M sodium phosphate-phosphoric acid buffer (pH 4.3). The effluent was oxidized and detected fluorometrically. 

Wild A, Winter A, Hager MD, Schubert US (2012) Fluorometric sensor based on bisterpyridine metallopolymer detection of cyanide and phosphates in water. Analyst 137 2333-2337... 

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