Perkin-Elmer spectrophotometers

Pectolytic activity was also studied in batch reactors, following the reaction progress in thermostated quartz cuvettes. The reaction medium (3 cm ) was prepared with 1.5 g/L pectin in the standard buffer and 0.063 mg of enzyme. The absorbance of the reaction mixture against the substrate blank was continuously recorded at the spectrophotometer (Perkin Elmer Lambda 2, USA). Typical reaction time was 15 minutes, but initial reaction rates were estimated considering only the absorbances recorded during the first 200 seconds, range of totally linear response. 

The above two modifications have been duly incorporated in a double-beam spectrophotometer. Figure 21.6, depicts the schematic diagram of the optical system involved in a Lambda-2 microcomputer-controlled UV-VIS Spectrophotometer (Perkin-Elmer). 

Apparatus. Infrared spectroscopy, Perkin-Elmer Model 257 infrared spectrophometer, Perkin-Elmer Corporation (Norwalk, CT) ultraviolet spectroscopy, Perkin-Elmer Model 559 UV-vis spectrophotometer, Perkin-Elmer Corporation, Coleman... 

An atomic absorption spectrophotometer (Perkin-Elmer 4000) was used with standard operating conditions to determine dissolved and total Mn, irrespective of oxidation state. Dissolved organic carbon was determined with an organic carbon analyzer (Beckman model 915B TOCmaster). 

Apparatus Use a suitable atomic absorption spectrophotometer (Perkin-Elmer Model 3100 or equivalent) fitted with a graphite furnace (Perkin-Elmer HGA 600 or equivalent). Use a lead hollow-cathode lamp (Perkin-Elmer or equivalent) with argon as the carrier gas. Follow the manufacturers directions for setting the appropriate instmment parameters for lead determination. 

Apparatus. Infrared spectrophotometer Perkin-Elmer model 421 recording spectrophotometer or equivalent, equipped with 6X beam condenser and holder for 1.5-mm. diameter KBr, discs. 

Fig. 10. Improvement of the infrared spectrophotometer. Infrared spectra of fully oxidized bovine heart cytochrome c oxidase cyanide derivatives measured with (A) a dispersive infrared spectrophotometer (Perkin-Elmer Model 180) and (B) a FTIR spectrometer equipped with a mercury/cadmium/tellurium detector (Perkin-Elmer Model 1800). Concentrations of the enzyme (O.VmM) and cyanide (19.4 M) were identical in both measurements.

The infrared absorption spectrum of gemifloxacin mesylate was recorded on FT-IR model Spectrum BX spectrophotometer (Perkin-Elmer, USA) using a KBr disc ( 2 mg of gemifloxacin mesylate was dispersed in 200 mg KBr). The obtained infrared spectrum is shown in Fig. 4.3, and the assignments of the characteristic bands are tabulated in Table 4.2. 

Infrared (IR) spectra were recorded using an IR spectrophotometer Perkin Elmer model 399B on KBr pellets obtained by pressing under reduced pressure a mixture of 1 mg sample and 400 mg KBr, spectrometry grade. 

To determine the stability of ascorbic acid under the various concentrations of citrate buffer and pH, the following experiment was performed with the use of a double wavelength, double beam, spectrophotometer (Perkin-Elmer 557). 

In order to obtain information about the binding parameter for the intercalation process, the absorption spectra of solutions containing a constant concentration of PF and varing amounts of DNA were measured by using a spectrophotometer (Perkin-Elmer, Model 552). 

Infrared spectra of all the catalysts were recorded on spectrophotometer (Perkin-Elmer 1600 FTIR) in the frequency range 1000-400 cm" ... 

The HPLC was a Du Pont 8800 quaternary solvent system with a Hewlett-Packard (HP) 1040A photodiode array detector (5-8). Flexible disks were used for data storage, and postrun data evaluation was performed by the detector s computer (HP 85). Samples were injected with a loop injector 10 p,L was used for analytical scale, and 200 jlL was used for preparative scale. Spectra were run on a spectrophotometer (Perkin-Elmer Lambda 3) for static absorbance and on a spectrofluo-rometer (Perkin-Elmer MPF-66) for fluorescence. Field-ionization mass spectra were obtained at a resolution of 45,000 (corresponding to a 0.01-daltons error for a mass of 450). 

IR Measurements. IR measurements were made on 1430 Ratio Recording Infrared Spectrophotometer (Perkin-Elmer). Nad cells were used. 

In this procedmre, the phospholipids are first adsorbed on silicic acid from chloroform-acetone solution, and the nonadsorbed lipids are measured in carbon tetrachloride solution with a high-resolution infrared spectrophotometer (Perkin-Elmer Model 421). Absorbance readings are taken at stationary instrument settings (frequencies or wavelengths) corresponding to the carbonyl absorption peaks of triglycerides and cholesteryl esters. From suitable calibration data, concentrations of these two components can be calculated. 

Figure 5. Diffraction from a CCA of PNIPAM spheres at 10 C and at 40 C. The spectra were recorded using a UV-visible-near IR spectrophotometer (Perkin Elmer X-9). The dispersion was contained in a 1.0 mm quartz cuvette oriented at normal incidence to the incident beam. The observed diffraction switching behavior was reversible these spectra were recorded after the seventh consecutive heat-cool cycle. Inset Pictorial representation of the temperature switching between a swollen sphere array below the phase transition temperature and an identical compact sphere array above the transition (Adapted from ref 16).

The polymerization reaction was followed in situ by RTIR spectroscopy by using either a dispersive IR spectrophotometer (Perkin Elmer 780) or a Fourier transformed IR spectrophotometer (Brucker IFS 66) equipped with a MCT detector cooled by liquid nitrogen. The time resolution of the dispersive instrument was 100 ms. For the FTIR spectrophotometer, the number of spectra taken per second depends on the spectral resolution and varies between 57 at 4 cm and 100 at 12 cm ... 

Uric acid was determined by the method of Archibald (2). Calcium was determined using atomic absorption spectrophotometry (atomic absorption spectrophotometer Perkin Elmer 107). 

Atomic Absorption Spectrophotometer (Perkin-Elmer Model 603)... 

The presence of amide in fatty amides was determined by FTIR spectra. FTIR spectra of the products were recorded by the FTIR spectrophotometer (Perkin Elmer FT-IR-Spectrum BX, USA) using KBr disc technique. The presence of amide (CO NH) proton in fatty amides was... 

The chemical structures of the palm fibers were evaluated by FTIR. The spectra were obtained on an FTIR spectrophotometer (Perkin Elmer). A sample was prepared by mixing the material and KBr in a proportion 1 200 (w/w). For each sample, 16 scans were accumulated with a 4cm" resolution. 

UV-VIS extinction spectra were measitred with a Lambda 35 spectrophotometer (Perkin Elmer, USA). Particle size distribution, based on hydrodynamic diameter, was evaluated by Nano S (Malvern, UK), a dynamic light scattering analyzer (DLS). Urueacted metal cations, extracted from the sample by a semi-permeable osmotic membrane (Visking tube), were detected by ICP-AES qirantitative analysis (Liberty 200, Varian, Austraha) in order to determine the reaction yield. Suspensiorts were dropped and dried on a copper grid, then observed by high resolution transmission electron microscopy (HRTEM) (Tecnai F20) and by the STEM mode with microanalysis EDX. 

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