Page 4 - Shimadzu AA-6880
P. 4

Enhanced Flame Analysis




                                                                                                                                      Advantages of the Double-Beam System

                                                                                                                                         Long-term stability                                       High sensitivity
                                                                                                                                                                                                                        A
                                                                                                                                         The graph shows the results of                            The graph shows the direct   b s
                                                                                                                                         measurements on 2 ppm copper (Cu)                         measurement results for 0.1
                                                                                                                                         conducted over at least one hour.   Absorbance            ppm lead (Pb).
                                                                                                                                         (The plot shows mean values for 11
                                                                                                                                         repeated measurements.) Over the
                                                                                                                                         course of more than 600
                                                                                                                                         measurements, the instrument          Measurement time                                Conc(ppm)
                                                                                                                                         achieved a relative standard   Data Showing Long-Term Stability for       0.1 ppm to 0.4 ppm Calibration Curve for Lead (Pb)
                                                                                                                                                                   Flame Cu Measurements
                                                                       Monochromator                                                     deviation within 1%.
                                               Detector

                                                                                                                                      Support for Developing Analytical Conditions

                                                                                                                                         Automatic gas flow rate optimization
                                                                                                                                         Automatic searching for optimal fuel gas flow rate (Japanese Patent 2099886). It is important
                                                                                                                                         to determine the optimal gas flow rate for the flame when using an organic solvent or after
                                                                                                                                         changing the burner height. The AA-6880F Series automatically optimizes the gas flow rate
                                                                                                                                         by measuring the changes in absorbance between a blank and a standard sample. The
                          Chopper mirror          Reference beam                                                                         difference between the two is displayed on the screen. The gas flow rate achieving the
                                                                                                                                         highest sensitivity is detected and this value is automatically set as the gas flow rate value.
                                                                                                  D2 lamp


                                                Sample beam
                                                                                                                                      Optional Autosampler Reduces Analysis Workload
                                                                                            Beam splitter                                Low carryover
                                                                                                                                         Great care must be taken to avoid carryover during flame analysis. The new ASC-6880
                                                                                                                                         autosampler rinses the nozzle at the rinsing port on the overflow mechanism after each   Discharge
                                                                                                                                                                          -4
                                                                                                                                         sample measurement is complete. This ensures 10  max. carryover during measurements
                                    Burner head (or graphite tube)                                                                       of multiple samples. The graph shows the results of consecutive analyses of 10 ppm, 20
                                                                                                                                         ppm, and 50 ppm sodium (Na) standard solutions in the EMISSION mode. No carryover
                                                                                                                                         could be detected when measuring the 10 ppm standard sample immediately after
                                                                                                                                         measuring the 50 ppm Na standard sample.                    Conventional method Overflow method  Data showing low carryover




                                                                                                                                      Trace Sample Analysis Using Micro Sampling

                                                                                                                                         Micro sampling
                                                                                     Hollow cathode lamp                                 At least 1 mL (1000 µL) volume of a liquid sample is required for the continuous intake of
                                                                                                                                         sample during normal flame analysis. With micro sampling, however, approximately 50 to 90   Sampling port  Sampling port
                                                                                                                                         µL of sample is injected in one shot into the flame and quantitation is based on the height
                                                                                                                                         and area of the peak signal obtained. This method offers the advantages listed below.
                                                                                                                                         Advantages                                                           Solenoid         Solenoid
                                                                                                                                                                                                                               valve
                                                                                                                                                                                                              valve
                                                                                                                                                                                                              (closed)         (opened)
                                                                                                                                            Permits analysis of small sample volumes
                                                                                                                                            Multi-element analysis of small sample volumes                 1. Sample injected into  2. Solenoid valve opens to inject sample
                                                                                                                                                                                                               micro sampling port.      in one shot into the flame.
                                                                                                                                            No blockage of burner slot with samples having a high salt concentration
                                                                                                                                            Synchronized with the autosampler for auto-dilution measurements
                                                                                                                                         * Synchronization with the autosampler requires the optional micro sampling kit.
                                                                                                                                         Example of micro sampling analysis
                                                                                                                                         Examples of the measured waveforms (overlaid) and calibration curve for micro
            Double-Beam Optics and Stable Hardware Achieve Superior Stability                                                            sampling analysis are shown to the right.
                                                                                                                                         A 2-ppm Cu standard solution was prepared by auto-dilution using the autosampler.
            The AA-6880 Series incorporates newly developed 3D double-beam optics.                                                       The autosampler can also be used to conduct dilution measurements of the sample.
            The optical system has been designed to produce maximum performance for each measurement method through                      (Injection volume: 90 µL)
            optimal adjustment of the light beam and light beam digital filter, and by using optical components that restrict light
            losses.



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