Sequential bench-top Spectrometer
The Perkin-Elmer Plasma 40 is a compact sequential ICP emission spectrometer that fits on a standard laboratory benchtop. The monochromator covers the spectral range from 160 to 800 nm and has two gratings used in the first order. For the U.V. region, a blazed holographic grating with 4200 lines/mm and blazed at 210 nm is used. For the visible wavelength range, a ruled grating with 1800 lines/mm and blazed at 490 nm is used. Grating selection and wavelength calibration are performed automatically. The spectral resolution at 320 nm is 0.019 nm. Background correction can be automatically or manually implemented using multiple point, off-peak compensation. Typical analytical throughput, when the lines are within a 50 nm wavelength range, may be up to 20 elements per minute. It is inversely related to the wavelength range to be covered. The monochromator can be purged to extend the useful wavelength range to 160 nm. The internally mounted rf generator has a “free-running” oscillator type with a nominal central frequency of 40 MHz and a maximum operating power of 900 W. Rf shielding and filtering are according to FCC, VDE and CSA regulations. The plasma torch assembly includes a corrosion-resistant Ryton R sample introduction system (endcap, cross-flow nebulizer and spray chamber). The demountable torch uses precision-bore quartz tubing for the outer and intermediate argon flow. The sample aerosol injector may be either alumina (standard) or quartz (optional). A built-in peristaltic pump provides constant solution flow at nominal rates of either 1 or 4 ml/min. The load coil does not require water cooling.
All operating parameters are controlled by an IBM PC series computer or a compatible one with at least 512 kbyte RAM, two 360 kbyte floppy disk drives, a Hercules monochrome/graphics adapter, a 12-inch monochrome monitor, a system clock and IBM PC DOS 2.1 or higher. An IEEE-488 (GPIB) interface controls communications between the computer, the instrument and peripherals (e.g. the AS- 51 autosampler). Analytical results are displayed on an Epson FX-85 printer. A O-10 V analog output is also provided for use with laboratory chart recorders. The system software includes five modes (ELEMENT, METHOD, REPORT, LIBRARY and EXEC) which are selected via the IBM PC function keys. ELEMENT mode is used to create element and line files. Line files include the wavelengths for the line and background correction, PMT voltages, integration times and data for up to five standards. Spectrum files are used to define the parameters for displayed spectra (wavelength range, read delay, etc.). A maximum of nine spectra may be displayed simultaneously and background correction points indicated on demand. The METHOD mode allows the operator to create customized, multi-element method files and to implement analyses in either the RUN, MANUAL or RUN AUTO modes. Analytical parameters such as number of replicates, read delay and output format may be specified. Up to 80 element files may be included in each method. Screen graphics are used during an analysis to monitor peak shape and emission intensity. The AS-51 autosampler may be used for fully automated analysis. REPORT mode allows selection of the report format and the desired data (intensities, intensity ratios, concentrations) and provides additional data handling and customized report generation facilities. EXEC mode allows the operator to easily program a sequence of instrument commands from the keyboard and function keys. The command sequence is then stored in an EXEC file. The LIBRARY mode provides access and manipulation of all ELEMENT, SPECTRUM, METHOD, DATA, EXEC and REPORT files.
