Milton Roy

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%. 

All assays performed on digester samples were conducted in 100 mM Tris buffer pH 7.5 with substrate incubations at 37 C. Glucose-releasing assays used the same Tris buffer with 0.5% sodium azide added. Colorimetric products from enzyme assays were detected and recorded using a Milton-Roy model 601 spectrophotometer equipped with sipper and data printer. 

SEC System, Data Processing, and Chromatography Procedures. The SEC/LALLS system contained a Model IlOA pump (Altex), Model 7125 injector (Rheodyne), KMX-6 Low-Angle Laser Light Scattering Photometer (LDC/Milton Roy), and a Model 98.00... 

Differential Refractometry (dn/dc). Stock solutions of polymer were prepared with known concentrations (w/v) in the solvent of choice, and the specific refractive index increment (dn/dc) was measured at 26 deg C with a KMX-16 Laser Differential Refractometer (LDC/Milton Roy). Sample concentrations typically were ca. 5 x 10 3 gm/ml. 

Low Angle Laser Light Scattering Photometry. Weight-average molecular weights were determined with a KMX-6 photometer (LDC/Milton Roy). The light source was a 2 mW vertically polarized helium-neon laser (A =... 

Chromatography conditions. HPLC was performed using a Milton Roy HPLC system (Riviera, FL, USA), consisting of a Constametric 3000 Series isocratic pump, a Rheodyne injector (Rheodyne L.P., Cotati, CA, USA), and a... 

Milton Roy, in Sample Preparation Accessory (SPA), Milton Roy, LDC Division, Riviera Beach, FL, USA. 

Samples were eluted in the reverse direction by using the Milton-Roy pump with the pulse dampener removed. The eluant flow (50-75 mL/min at 200-300 lb/in.2) was monitored at 254 nm by using an Altex 153 detector with a biochemical flow cell. Elution with each solvent was continued until the detector response returned to base line. All columns were eluted with acetonitrile this solvent was preceded by 4.5 M NaCl/0.04 M HC1 and 0.04 M HC1 elutions on the MP-1 column and by 4.5 M NaCl and distilled water elutions on the MP-50 column. The aqueous column effluents were adjusted to pH 2 (MP-1) or pH 11 (MP-50) and then extracted three times with dichloromethane. The acetonitrile column effluents were saturated with NaCl to separate the water, which was extracted twice more with acetonitrile. Fifty percent aliquots of the processed organic solvents from each respective column were concentrated in Kudema-Danish evaporators to a final volume of about 10 mL (any remaining water was removed as the low-boiling azeotrope in the process) to give 25,000 1... 

The salt water circulating system proved to be one of the most troublesome problems, because of rust build-up in the recirculating system. However, this was solved by pumping the sea water through only once. The sea water is pumped from a 5-gallon glass bottle by a Milton Roy stainless steel positive-displacement, variable-volume pump which has a maximum capacity of 1.1 gallons per hour at 950 p.s.i. The sea water is collected in a pressure tank with a controlled air pressure dome. 

For the calibration and evaluation of kinetic response of pH electrodes, a Milton-Roy sapphire and Hastalloy pump (capable of 6,000 psi) were built into the pressure line in order to feed acid, base, or buffered solutions through the test vessel by way of stainless capillary tubing of 0.030-in. i.d. Outflow from this system can be controlled by means of two Hoke Micro-Metering valves which, when mounted in series, can provide an "engineered leak with an outfall that can be matched by the pump to allow system flows from 0.6 cm3/min to 16 cm3/min. Such a pumpable system allows fresh reference solution to be continuously added to the system while maintaining constant pressure. This avoids a possible pH drift caused by reactions between the walls of the test chamber and the reference solution. This system also allows... 

Figure 9.28. Optical diagrams for refractive index detectors for LC (a) Fresnel type by permission of LDC/Milton Roy (h) deflection type by permission of Millipore Corporation, Waters Chromatography Division.

Before each experiment, the jacketed stainless steel (Top Industrie, Dommarie-Les-Lys, France) reactor is opened. A precise amount of substrates and water (Table 2) are introduced within the reactor. After sealing, pressurization is achieved by pumping liquid carbon dioxide (Minipump, Dosapro-Milton Roy, Pont-St-Pierre, France) to the desired final pressure (12.5 MPa). The reactor is then isolated from the C02 circuit. Then 20 mg of lipozyme TM of various diameter distributions (Table 1) is introduced in the reactor with an original system, giving the zero time of the reaction and the stirring is switched on. A 6-way UPLC valve (Rheodyne 7125) permits to withdrawn 50 pi samples for analysis without depressurization. 

A Milton Roy pump was used for introduction of liquid feeds into the reactor. In runs with such feeds, the storage burette, the pump head, and the feed lines were heated to maintain appropriately low viscosity for pumping. The selected pressure of the system was maintained bv a pressure regulator attached to the hydrogen cylinder. The hydrogen flow rate was controlled by a Brook s high pressure rotameter, and by two needle valves at the outlet (Figure 14). 

LDC/Milton Roy/Ghromatix Technical Note LS 7, Division of Thermo Separation Products, Rivera Beach, FL, 1979. 

The HPLC equipment consisted of a Milton Roy CM4000 ternary gradient pump, a lOOm Reodync sample injection valve, and a Reodyne valve for solvent back flushing, which was controlled by a Spectra Physics 4270 integrator to carry out the data acquisition. 

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