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These are Specific Procedures for the Graphite Furnace and Flame operations.
GENERAL INFORMATION: The AAnalyst 800 atomic absorption (AA) spectrometer features a combined flame/graphite furnace. It provides automatic exchange of the atomizers (controlled via computer), whereas previous instruments' had to be changed by hand. This improves reproducibility, saves time, and is easier to use. Solid-state detector technology and simultaneous background correction have quieted background noise and boosted detection sensitivity anywhere from 5 to 20%. Specific protocols are described: General User Guide, Graphite Furance, and the Flame Burner. Users must be familar with the procedures for care and cleaning of the instrument..
Model Spectra AA 800
FEATURES
Real Time Double Beam Spectrometer with Wavelength Range 190 - 870 nm.
High-efficiency
optical system for lowest detection limits At the heart of these
advanced AAnalyst systems is an exceptionally efficient optical
system featuring a unique solid-state detector with a photoactive
surface optimized to provide the highest quantum efficiency in
the UV region. Combine our state-of-the-art detector with proven
monochromator efficiency and spectrometer throughput, and even
elements such as As and Ba can be measured with outstanding signal-to-noise
ratios.
Longitudinal Zeeman-effect
background correction provides lowest detection limits With longitudinal
Zeeman-effect background correction, the amount of light throughput
is doubled by eliminating the need for a polarizer in the optical
system. All other commercial Zeeman designs incorporate inefficient
polarizers that reduce light throughput and diminish performan
ce. With
this unique design, the AAnalyst systems provide the lowest detection
levels available. To further improve detection levels and accuracy,
the AAnalyst systems also include optimized sampling frequency
and interpolated background correction.
THGA furnace provides uniform temperature distribution -- The patented THGA tube used in the AAnalyst systems
provides a uniform temperature distribution along its entire length.
This eliminates cooler temperatures at the tube ends and removes
most interferences. With the THGA tube design, accuracy and sample
throughput are improved by reducing the need for the time-consuming
standard additions technique.
Consistent temperature control enhances performance -- In conventional furnace systems, the heating rate
during atomization depends on the input-line voltage. As voltage
varies from day to day, season to season or among laboratory locations,
so does the heating rate. The AAnalyst high-performance systems
use enhanced power control circuitry to maintain a uniform heating
rate, so no matter where a system is located, you can be sure
that it provides outstanding, consistent performance.
WinLab32 software
Designed with extensive input from laboratory managers and AA
users around the world, WinLab32 software provides all the tools
and features needed to start running samples quickly and meet
the requirements of today’s laboratory. Easy to learn and
easy to use The extensive Wizard features of WinLab32 make complex
tasks easy with step-by-step instructions and Tool Tips, provides
additional information about screen text and entry fields. Status
panels display the status of each instrument component for easy
monitoring. The Analysis List combines standard, sample and method
information into one list, showing the exact order in which the
analysis will be run. This list also displays the analysis status
at all times and can be printed as a summary at the end of the
run. Improved productivity WinLab32 software improves laboratory
productivity
by reducing the time required for method development, sample analysis
and report generation. Furnace method development is completely
automated, helping to optimize the pyrolysis and atomization temperatures
as well as sample and modifier volumes. You can create methods,
review or reprocess data offline, even add samples anytime during
an analysis, without
interrupting the active analysis. Recall Calibration eliminates
the need for initial calibration, while Edit Calibration gives
you complete control over the quality of your calibration curve
before you proceed with QC and sample analysis.
This procedure must be modified for the 800
An example of step by step AAS instructions for an Iron Method illustrating typical operation of the Perkin Elmer 5100 aa:
1.
Turn on AAS, computer, and printer.
2. Double click on the Instrument Icon from Windows initial screen.
3. The WinLab32 for AA window will open - do not proceed until
the 5100 icon underneath the AAS icon is highlighted.
4. While you're waiting for the icon to light up, open your acetylene
tank and air line. Acetylene pressure should be at 14 psi (this
is marked on the gauge in black) and air pressure should be about
45-50 psi (neither air pressure nor acetylene pressure should
vary much between sessions, but it's important to always check
it, especially after changing tanks). The gauge that reads pressure
in the tank is the gauge on the right. The gauge on the left reads
how much fuel is in the tank. NOTE: when first opened, the acetylene
tank, will usually read above 15 psi (red zone). Don't adjust
the pressure right away, because 93% of the time, after about
10 minutes, it will have sunk to 14.1 psi always check the pressu
re after you light the
flame. NOTE: the acetylene tank should be replaced when the fuel
level drops below 75 psi (using the scale on the inside of the
circle on the left hand gauge). Since contaminants sink to the
bottom of the tank, it is not advisable to drain a tank to absolute
empty .
5. Under "Windows" at the top of the page, scroll down
and open the Element Parameter file. This file is your method
file; you can't run an element unless you have defined a method.
6. The Element Parameter file will ask you whether you want a
previously defined file, or a new one (so it is possible to use
the same method for different sample runs). In the Element Parameter
file, you have three pages to fill out - Main, Calib, and Options.
7. Main
8. - specify the element (standard wavelength and slit width will
automatically appear), select an appropriate sampling time (default
is 5 sec), make sure the flame sensor is on, and confirm that
the fuel is acetylene and the oxidant is air. "Time average"
and "AA" remain as is. Calib
9. (Calibration) - enter the concentration of your standards and
how you want to refer to them (i.e. Sl, or standard 1, or whatever).
The most important thing to do is to make sure that if, for example,
you have a 10 ppm standard, the standa rd units are set at mg/L.
To change standard and sample units you just double click on the
line. It is possible to have standard units and sample units different.
You decide the number of significant digits (up to the machine's
precision level of course) by entering "5.0" as a standard,
or "5.00", etc. Last, click on Nonlinear to change the
type of standard curve that will be drawn; absorbance vs. concentration
for Fe is only linear up to about 10 mg/L. Options
10. - highlight the printing options you prefer and type in any
comments about your samples. This page prints out at the beginning
of your run automatically. Save your Element Parameter file. The
computer will always use the Element Parameter file most recently
opened when you begin running samples. Close your newly named
file.
11. You should be back at the Lab Benchtop. Now you will open
four files that you will need to manually run your samples. Under
Windows, scroll down and select "Flame Control", "Manual
Control", "Display Calibration", and "D isplay
Data".
12. OK, but before you begin running samples, you need to adjust
the lamp, and then optimize the burner head position, the fuel,
and the nebulizer.
13. NOTE: For Fe, you must use the longer burner head with
the BLACK PIN. When running samples that use acetylene and air,
you use the longer burner head with the black pin, but for any
elements that require the hotter N20 flame, you use the shorter
burner head with the red pin. I know from experience that the
AAS will not light if you mix up the burner heads!
14. Adjust the lamp by first opening "Adjust Lamp" under
Windows (see, there really is logic to all this; before you know
it you won't need this sheet!). If you have created your Element
Parameter file (as you should have by now) the AAS has already
selected the Fe lamp. Your lamp current should read 25 or 30,
and your lamp energy should be in the 60's or 70's [in the past
lamp energy has fluctuated, and Perkin Elmer maintains that even
at a low lamp energy precise sample measurements are possible,
but if lamp energy drops dramatically it is probably a sign something
is wrong - call Perkin Elmer!]. Now, open the lid covering the
lamps, and maximize the absorbance bar by 1) moving the whole
lamp forward and backward and 2) turning the two knobs you will
see near the
15. back end of the lamp, which adjust the lamp's position.
16. Optimize the vertical position of the burner head by first
lowering the burner head with the large right hand knob next to
the nebulizer. Then open "Continuous Graphics" under
Windows and Autozero by clicking on "Autozero" under
< B>Continuous. Raise the burner head until you get a reading,
that is, when your .000 goes up, to .004, then .018, etc. Lower
the burner head until you have 0.000 again, then lower it one
quarter of a turn more.
17. Now it's time to light the AAS. Don't close your Continuous
Graphics window, just click on the Flame Control window. After
opening your air and acetylene lines (air comes through a line
from a compressor next door, acetylene is in a tank) click on
the flame icon to light the flame. By the way, the exhaust system
should be turned ON now!!
18. Adjust the fuel and oxidant levels by using the Fuel Up/Down
and Oxidant Up/Down keys on the keyboard (towards the right on
the top line of F keys). For iron, I have found that a fuel of
2 and an oxidant of 8 - 10 works well. Basically, you wa nt a
lean flame (meaning the blue line on the burner head at the bottom
of the flame is about 1/8" high). You don't want a rich flame,
which is the result of a high fuel level.
19. To adjust the burner head horizontally and diagonally, go
back to the Continuous Graphics window. While aspirating a standard
(you'll probably want to make more of the standard you choose
to aspirate, since a lot of liquid can be used up in thi s step)
turn the large shiny left hand knob (horizontal) in both directions
until you reach maximum absorbance. Repeat this process with the
inside-the-compartment-to-the-right-of-the-burner-head shiny knob
(diagonal). Some people like to readjust the ver tical knob at
this point, to fine tune it. I don't, but try it yourself and
see what you prefer.
20. The nebulizer is also adjusted using the Continuous Graphics
window. Loosen the lock on the nebulzier by turning the "locking
ring" counterclockwise. This will allow you to adjust the
sample flow rate by twisting the "knob ring"; the knob
ring being the ring which the nebulizer tube directly connects
into (the locking ring is immediately behind the knob ring, touching
the knob ring in fact when it is completely tightened). When the
nebulizer tube is no longer locked (i.e. the locking ring has
b een loosened) you can adjust the rate at which the tube sucks
samples by twisting the knob ring. Now, put the nebulizer tube
in a standard, and turn the circular knob ring until bubbles come
OUT of the tube in your standard; then turn the circular knob
ring in the other direction until you reach a maximum absorbance
on your Continuous Graphics window.
21. NOTE: it is my experience that the nebulizer sucking rate
does not change much at all in between running samples. When you
have a good rate, I recommend not messing with it unless you're
having problems. Once you have adjusted the nebulizer using absorbance
a few times, you will get a fe el as to what is a good rate for
the solution to drop in the neck of the volumetric flask. NOTE.
Remember to always "relock" the locking ring after making
an adjustment!!
22. Now you can close the Continuous Graphics window. Then, click
on the Manual Sampling window, where you will want to double click
on the line above the "save data on/off" icon, to name
the file where your sample data will b e stored. If you do not
name a file and thereby cause the "save data on/off"
icon to be highlighted, your data will not be saved!!!
23. Now you're ready to begin running your standards/samples.
You will always begin a sample run by running a standard curve.
Simply put the nebulizer tube in your first standard (your "zero"
standard") and scroll down under Calibration to autozero
. When the READ icon stops being highlighted, that means the AAS
is finished reading that standard, so you will remove the tube,
wipe it with a ChemWipe, put it in your second standard, and scroll
down to your next standard . Repeat this process until all your
standards have been analyzed. NOTE: some people think the neb
tube should always be placed in distilled water in between samples,
to flush the tube. I have tried it with and without the de-ionized
water and found that if you let the nebulizer tub e sit in your
standard for one second before its analyzed, then you don't need
to do the distilled water wash every time. I tell the AAS to delay
analyzing the standard/sample after I hit READ by typing in 1.0
second Delay in the Elem ent Parameter file, Main section. Experiment
yourself!
24. You have to use the mouse to analyze standards (and the nebulizer
tube must be in the standard before you click on autozero, Sl,
S2, etc.) but to analyze samples you can either use the mouse
to click on the large READ icon on the Manual Cont rol screen
or the keyboard (in the middle, top row). After your first standard
curve is run, rinse with de-ionized water and then put the nebulizer
tube in your first sample, hit READ (mouse or keyboard), and then
keep the tube in the sample un til the READ icon is no longer
lit up. Rinse with de-ionized water, then put the tube in your
next sample, hit READ, wait, etc. I recommend running a standard
curve after every 10 to 15 samples. In between every sample, I
always wipe the neb ulizer tube with a ChemWipe.
25. The Display Data window will show you the concentration of
your most recent sample/standard. The Manual Control window will
keep track of the total number of samples/standards you've run.
To view your most recent standard curve, click on the Display
Calibration window. To edit a standard curve, click on Edit Calibration.
26. When you've finished running all your samples/standards, you
turn off the flame (using keyboard or Flame Control window), close
the acetylene/air lines, and bleed the gases remaining in the
lines (click on bleed gases in Flame Control window).
27. To save your data file in, for example, ASCII, so that you
can transfer the information into a spreadsheet, go to the Data
Benchtop. Then scroll down to Reformat Data. A window will open
that will allow you to call up your data fi le (double click on
the data line), and then choose various options for what you want
saved in your ASCII file. The options are too numerous to list
here; most are pretty straightforward, but for a detailed listing
consult the manual. Once you've made your choices, simply click
on Execute Reformat.
28. To view your ASCII file, exit the software. At the C prompt,
type x. Scroll up using the arrow keys until you find Data - AAS.
Hit return twice and you will see a listing of all the Data files.
Then follow the commands at t he bottom of the page: hit V to
view the document, C to copy it onto a disk, etc.
AAnalyst 800
Atomic Absorption Spectrometers
Specifications
System Design: The AAnalyst™ 800 is a fully-integrated benchtop
design atomic absorption
spectrometers, incorporating all spectrometer, flame and graphite
furnace components in a single instrument,
offering fully automated exchange of flame and furnace atomizers
at the touch of a button.
Optical System Photometer: Real-time double-beam optical system
(single-beam for Zeeman furnace operation with the
AAnalyst 800). Front-surfaced, reflecting optics with protective
coating. Optical system sealed within protective
cover.
Monochromator: Littrow design with motorized drive for automatic
wavelength selection and peaking.
Wavelength range: 190 - 870 nm. Diffraction grating: 1800 lines/mm
blazed at 236 nm and 597 nm. Grating area:
64 x 72 mm. Reciprocal linear dispersion: 1.6 nm/mm (nominal).
Focal length: 267 mm. Spectral bandwidths:
0.2, 0.7 and 2.0 nm, dual height; motorized slit drive for automatic
slit selection.
Detector: Wide-range segmented solid-state detector, including
a built-in low-noise CMOS charge amplifier array.
Automatic Lamp Selection: 8-lamp holder with built-in power supplies
for hollow cathode and electrodeless
discharge lamps. Computer-controlled lamp selection and alignment
via AA WinLab™ software. Lamp elements
and recommended operating currents are automatically recognized
and set when using Perkin-Elmer Lumina™
hollow cathode lamps.
Flame System Gas Controls: Fully computer-controlled with oxidant
and fuel monitoring. Keyboard-actuated remote ignition
system with air-acetylene. Acetylene flow is automatically adjusted
prior to the oxidant change when switching
to or from nitrous oxide-acetylene operation. TotalFlow™
control of the oxidant and fuel gases for constant
fuel:oxidant ratio.
Safety Functions: Interlocks prevent ignition if the proper burner
head, the nebulizer/end cap, or the burner drain
system is not correctly installed; the liquid level in the drain
vessel is incorrect; or gas pressures are too low.
Interlocks also will automatically shut down burner gases if a
flame is not detected, or if any of the other interlock
functions are activated. Provision is included for safe shutdown
from all operating modes in the event of a power
failure.
Burner System:
Premix burner design that can be moved automatically into the
sample compartment via software control and a motorized carriage.
Alignment of the flame in the light beam is fully automatic, using
a motorized
burner mount for vertical and horizontal burner adjustment and
automatic software-controlled self-optimization of the burner
position. The burner is equipped with a high-strength inert mixing
chamber, angled to ensure proper
drainage. Includes adjustable Universal GemTip™ corrosion-resistant
nebulizer and an all-titanium, 10-cm, single-slot burner head
for air-acetylene operation.
Background AAnalyst 800: Continuum source double-beam background
correction using a high-intensity deuterium arc lamp.
Correction AAnalyst 800: Longitudinal AC Zeeman-effect background
correction using a modulate 0.8 Tesla magnetic field oriented
longitudinal to the optical path. The magnet is automatically
switched on during the atomization step only. Rollover detection
is built-in. Also built-in is continuum source double-beam background
correction for uses with flame operation.
Furnaces AAnalyst 800: Built-in fully computer-controlled Transversely
Heated Graphite Atomizer (THGA™). The graphite tube is transversely
heated providing a uniform temperature profile over the entire
tube. AAnalyst 800: The graphite furnace can be moved automatically
into the sample compartment and positioned via software control
and a motorized carriage. An external protective gas stream around
the graphite tube prevents the entrance of outside air to maximize
tube life. An internal purge gas goes through the graphite tube
to remove the volatilized matrix vapors during drying and thermal
pretreatment. The two gas streams are computer-controlled independently.
Pneumatic opening and closing of the furnace for easy tube change.
Common Furnace Program Flexibility: Analytical programs with up
to 12 steps can be set up. Each step can be programmed
Features: with the following parameters:
Temperature: Ambient up to 2600°C (up to 3000 °C with
AAnalyst 800) in steps of 10 °C.
Ramp Time: 0 to 99 s in steps of 1 s.
Hold Time: 0 to 99 s in steps of 1 s.
Internal Gas Flow: 0 mL/min (gas stop), 50 mL/min (mini-flow),
250 mL/min (full flow); can be switched over
to another type of gas (Alternate Gas).
Furnace Opening and Closing: Pneumatically-operated by software
command.
Required Inert Gas: Argon. inlet pressure 300
kPa (3 bar) minimum. Maximum gas consumption is 700 mL/min
with the AAnalyst 800, 1220 mL/min with the AAnalyst 800.
Water Coolant: A circulatory cooling system is included with the
AAnalyst 800.
When operating the AAnalyst 800 without the circulatory cooling
system, cooling water meeting the following
specifications should be used: Sediment-free drinking water; 20-40
°C; flow rate not less than 2 L/min; pressure
between 2.5 and 4.5 bar; pH between 6.5 and 7.5; hardness not
greater than 14°dH or 100 ppm.
Furnace Sampler Table: Installed in front of the furnace unit.
Removable sample tray with 88 and 146 sampling
Autosampler positions for sample and reference solutions and 1
overflow container for pipet washing. Minimum sample
requirement: ca. 0.1 mL.
Dispensable Volume: Sample and Reagent: 1...99 mL, selectable
in increments of 1 mL.
Max. dispensable Vol. 99 mL (sample volume + reagent volume).
Flushing volume 1.3 mL, fixed.
Electronics: The autosampler is powered from the spectrometer
and is software-controlled.
Data Control Complete PC control using AA WinLab software operating
under the Microsoft® Windows 95® operating
System environment. Provides complete control of the instrument
and its major accessories plus data handling and storage.
Data Handling: Instrument readings linear in absorbance (-0.500
A to +2.000 A), concentration or emission
intensity with continuously variable scale expansion from 0.01
to 100 times. Integration times operator-selectable
from 0.1 to 60 sec. in increments of 0.1 sec. Reading modes include
time-averaged integration, non-averaged
integration (peak area), and peak height measurement. Includes
built-in statistics. Up to fifteen (15) standards and
a choice of proven calibration equations. Reslope of the analytical
curve using a single operator-selected
calibration standard. Built-in IEEE-488 interface for computer
connection and use of optional accessories.
Minimum PC Configuration: Intel® Pentium® processor; 90
MHz; 16 MB RAM; 1 serial, 1 parallel
(bidirectional) interfaces; 500 MB hard disk drive; 3.5"
disk drive; CD-ROM drive; SVGA graphics board and
compatible monitor; mouse pointer; MS Windows 95. A compatible
printer is required for hard copy data display.
Dimensions AAnalyst 800: 110 cm wide x 65 cm high x 70 cm deep
(104 cm deep with furnace autosampler).
AAnalyst 800: 187 kg (without controller and cooling system).
Power 230 V (+5%/-10%), 50/60 Hz; 5000 VA (AAnalyst 800).
Requirements Electrical Protection: As defined in EN 61010-1-1993
(IEC 1010-1); insulation class I; insulation category
(overvoltage category) II; pollution degree 2. Technical Certification:
Designed and tested to be in compliance with the legal requirements
for technical instruments Standards including IEC 348 and VDE
0411 and CSA 22.2 No. 151 and the U.S. Federal Communications
Commission standards for radio frequency interference. Also complies
with German legal requirements for radio interference suppression
(better than grade A/0871). The instrument is developed and produced
in compliance with ISO 9001.
The AA WinLab software provides required control parameters for
GLP and instrument performance validation.
Safety and EMC standards: EN 61010-1-19993 (IEC 1010-1: 1990 +
A1, A2, modified). Electromagnetic
compatibility: EN 50 081-1:92 for emission, EN 50 082-1:92 for
immunity.
Environmental Ambient temperature: +15 °C to +35 °C. Relative
Requirements humidity: 20 to 80% non-condensing.
Cooling System Self-priming recirculatory system with fan-assisted
heat exchanger (standard with the AAnalyst 800) for constant cooling
of the graphite furnace. Water temperature during operation approx.
36 °C; water flow 2.5 L/min.
Power requirements: 230 V (+5%/-10%), 50/60 Hz; approx. 140 VA.
Dimensions: 20 cm wide x 375 cm high x 50 cm deep,
18 kg with coolant.