Milton Roy Spectronic

The decomposition kinetics of the N-Br-amino acids was studied spectro-photometrically by following the fall in absorbance at the wavelength of the absorbance maximum of the N-bromoamino acid, in a Milton Roy Spectronic 3000 Array or a Beckman DU65 single-beam spectrophotometer, both equipped with a cell carrier thermostated to within 0.1 °C by water flow. Kinetic experiments were initiated using a hand-driven HI-TECH SFA-12 Rapid Kinetics Accessory with a 1.00 cm flow cell. 

The Milton Roy Spectronic(R)-20 definitely provides a low-cost and easy to operate instrument, that is still capable of achieving absorbance readings accurate to 1 or 2%. 

Ultrafiltration was used to determine the extent of europium binding to humic acid. While stirring, Eu(III) + Eu- 152 tracer was added to a 10 ml solution of humate at pH 4.2 (ace tate buffer) in an Amicon model 8050 ultrafiltration cell. After a 500 /xL aliquot was withdrawn for counting, the cell was immediately pressurized. An Amicon YM2 filtration membrane (1000 molecular weight cut-off) would retain the humic acid plus the bound europium while unbound Eu(III) would elute. One ml of filtrate was collected and tested for the presence of humate by measuring the visible spectrum of the solution with a Milton Roy Spectronic 1201. On cessation of filtration, 500 /xL aliquots were removed from the filtrate and the residual solution above the membrane. The samples were counted for the presence of Eu-152 in a well-type Nal(Tl) crystal connected to a single channel analyzer. 

The rate of Sm(III) dissociation from humic acid was studied using a ligand exchange technique. A solution of the Sm(III)-humate complex was equilibrated for a fixed time, then an aliquot of arsenazo III was added. The Sm(III)- arsenazo III complex is so stable (9) that it prevents reformation of the Sm(III)-humate. The rate of Sm(III)-Ars complex formation is quite rapid (9) and we found that the observed formation of the Sm(III)-arsenazo complex was determined by the rate of dissociation of the Sm(III)-humate. The formation of the Sm(III)-Ars complex was monitored spectrophotometrically by the increase in absorbance at 665 nm. Reactions were monitored either with a Milton Roy Spectronic 1201 (ti/2 ... 

The IR spectra of the polymers were measured on a Perkin Elmer 16 PC FTIR spectrophotometer. The NMR analyses were performed on a Bruker ARX 300 NMR spectrometer in deuterated chloroform using TMS as internal standard. The UV spectra were recorded on a Milton Roy Spectronic 300 Array spectrophotometer and the molar absorptivity (Emu ) was calculated on the basis of the repeat unit of the polymer. The relative molecular weights of the polymers were estimated using a size-exclusion chromatograph (SEC) system equipped with a Waters 510 HPLC pump, ultrastyragel... 

The stock solution of each dye was prepared as 20 mg/L except those insoluble ones. All the samples were put into the rotating merry-go-round in which they were exposed to same amount of UV light. 2 ml samples were removed from each quartz tube at predetermined time. The samples were analyzed under the respective absorption A.max for each dye by a Milton Roy UV-Visible spectrophotometer, model Spectronic Genesys-2. 

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