Varian SpectrAA 200 Atomic Absorption Spectrophotometer with Graphite Furnace Atomization

Software:

Complete instructions for developing a method and executing an analysis are beyond the scope of this introduction.  A person-to-person discussion with an experienced user is the best way to become familiar with the operation of the Varian Instrument.  The screenshots below will give you a little preview of what you will see.

Methods:

The collection of instrument and software parameters that defines how an experiment will be carried out is called a Method in the software.  You cannot run a A collection of methods, and associated data, can be stored in a Worksheet.  The screenshot below show the window that pops up after you have started the software, opened a New Worksheet, and have clicked on the Add Method button in the New worksheet window. 

A.  Load From:   Typically, you will select Cookbook here.  This will allow you to modify prefabricated methods to suit your needs.

B.  Method Type:   Select you vaporization/atomization source.  The instrument is typically configured with the graphite furnace in place, so Furnace is the typical choice here.

C.  Select an Element: From the list, scroll down and select your element of interest.  You can add matrix annotation as well.

Once you have made selections for each of these options, click OK.

Configuring a Method:

Once you have selected a general method for you analysis, you must configure several variable associated with the method.  If you selected a Cookbook method, suggestions for these variables will be made.  You may change these suggestions to suit your needs.

A.  Page Tabs:   This collection of tabs corresponds to a wide range of user-defined parameters for your analysis.  By viewing the window associated with each clickable tab, you can define things like calibration tolerance, background correction method, concentrations of standards to be used, temperature program for the furnace, and many other options.

B. Method Tabs:   It is possible to store more than one method in a worksheet.  If this is the case, each method will be represented by a tab.  Clicking on the appropriate tab will switch to the new method.

Collecting Data

Before collecting data, it is necessary to ensure proper alignment of the optics and of the sampling arm so that samples are deposited appropriately onto the platform inside the graphite tube.  It is also wise to flush the sample capillary with acid solution and run the furnace through a cleaning cycle.  Each of these operations is best learned by having an experienced user walk you through them.  Once they are complete, actual data collection can begin.   Data collection and analysis are initiated in the window shown below.

A.  Operation Buttons: These allow the user to perform instrument optimization, select the samples to be analyzed, and initiate and stop analysis.  Prior to pressing Start, cells in the sample table (labeled E) must first be selected using the Select tool (the green highlighter icon).

B.  Single Run Results:   This section of the window provides temperature and absorbance versus time plots for the current sample.  It is particularly useful for monitoring the sample to sample response of your solutions.

C.  Calibration Curve:  As data points are collected, they are added to this plot and the calibration curve recalculated.  Based on the tolerance you set in the Method window, the software will sound a warning if it appears that there are problems with the calibration.

D.  Numerical Data:  This table lists absorbance values for each blank, standard, and sample and %RSD (if replicate measurements were taken).

E.  Sample Table:  Results for individual samples are tabulated here.  These results are reported in concentration units and are calculated based on the calibration curve shown in C above.  Several runs can be stored in a single table by selecting blank cells for each run.