scinco Mega-900 UV-Vis User manual

0
5.
Mega-900 UV-Vis Spectrophotometer
Instruction Manual
Janurary 2016

Mega-900 SCINCO
Introduction
Thanks for your purchase of the SCINCO CO., LTD. Mega-900 spectrophotometer.
UV-Visible Spectrophotometer is a well-accepted, documented technique with many
applications. The technique is extensively used for the analysis of agricultural
products and is widely used in public health, environmental protection, life sciences
industries and many other organic and biochemical applications.
For obtaining maximum performance and trouble-free operation, we give you the
following suggestions:
◆Upon receiving your instrument, please check all the items listed in the
packing list are included and install the instrument according to the instruction
manual.
◆The spectrophotometer is a precise electronic instrument. Please read the
instruction manual carefully before operation. If the equipment is used in a
manner not specified by the manufacturer, the protection provided by the
equipment may be impaired.
◆Avoid collision and handle the instrument carefully during transportation.
◆If the tested solution is harmful to humans, please wear gloves or use other
protection methods.
◆Please keep the accessories in a safe place for the use in future maintenance.
For more information, please visit www.scinco.com

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Contents
Contents.....................................................................................................................I
Chapter 1 Instrument Introduction..........................................................................1
1.1 Components inspection....................................................................................1
1.2 UV/Vis spectrophotometer and method............................................................1
1.2.1 UV/Vis spectrophotometer method................................................................1
1.2.2 UV/Vis spectrophotometer ............................................................................1
1.2.3 Condition of measure method .......................................................................2
1.3 Components description ..................................................................................3
1.3.1 Front view .....................................................................................................3
1.3.2 Rear view......................................................................................................4
1.3.3 Side view ......................................................................................................4
1.3.4 Sample cell holder.........................................................................................5
1.4 Specifications...................................................................................................6
Chapter 2 Installation...............................................................................................7
2.1 Installation location.........................................................................................7
2.2 Installation......................................................................................................7
2.3 Start ...............................................................................................................8
2.4 Performance inspection in the installation process.......................................10
2.4.1 The accuracy and reproducibility of wavelength..........................................10
2.4.2 Flatness of the baseline ..............................................................................11
Chapter 3 Instrument operation ............................................................................13
3.1 About double beam measurement................................................................13
3.1.1 What’s the double beam..............................................................................13
3.1.2 How to use double beam instrument...........................................................14
3.2 Application examples ...................................................................................15
3.2.1 Photometric measurement example............................................................15
3.2.2 Spectrum measurement example................................................................16
3.2.3 Quantitative measurement example............................................................18

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Chapter 4 Optional accessories ............................................................................23
4.1 CH19-1 Thermostatic cell holder....................................................................23
4.2 DS19-1 Angle-changeable solid sample holder..............................................24
4.3 IS19-1 Integrating sphere...............................................................................25
4.4 LS19-1 Long pathlength cell holder................................................................26
4.5 MH19-1 Micro cell holder ...............................................................................27
4.6 MH19-2 Ultra-micro cell holder.......................................................................28
4.7 MR19－1 Specular reflection accessory.........................................................29
4.8 MS19-1 Manual 8-cell holder .........................................................................30
4.9 PS19-2 Sipper pump......................................................................................31
4.10 S19-1 Solid sample holder............................................................................33
4.11 SS19-1 Short pathlength cell holder..............................................................34
4.12 TR19-1 Test tube cell holder.........................................................................35
Chapter 5 Maintenance ..........................................................................................36
5.1 Points for attention:........................................................................................36
5.2 Daily care.......................................................................................................36
5.3 Trouble shooting and maintenance................................................................36
Appendix 1 Light source replacement..................................................................39
Replace the tungsten lamp...................................................................................39
Replace the Deuterium lamp ................................................................................40
Appendix 2 Fuse replacement...............................................................................42

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Chapter 1 Instrument Introduction
1.1 Components inspection
After the instrument has been unpacked, please check up carefully the parts provided
against the packing list for acceptance. In the event of error or damage, contact the
sales agent immediately for prompt solution. A complete set of the instrument is
according to the packing list in the instrument package. The packing list shall be taken as
the criterion. The company keeps the right to revise.
1.2 UV/Vis spectrophotometer and method
1.2.1 UV/Vis spectrophotometer method
UV/Vis spectrophotometer method is an instrument analysis method that
measures the molecule’s absorbance of radiation in ultraviolet and visible
spectrum. The absorption of molecule corresponds to the excitation of valence
electrons and electrons in the molecular orbital between different electronic energy
level, this method can be used for qualitative and quantitative analysis of organic
and inorganic compounds.
Lambert-Beer’s law is the basic law of radiation absorbance; it’s the foundation of
spectrophotometer analysis method. The absorbance (A) of solution is directly
proportional to the path length (b) and the concentration (c) when the wavelength
of the incidence light is fixed. Lambert-Beer’s law states that
ClA 

, where

is the constant of proportionality, called the absorbtivity.
1.2.2 UV/Vis spectrophotometer
UV/Vis spectrophotometer is the general analysis instrument which is basic on
the principle of UV/Vis spectrophotometer method. UV/Vis spectrophotometer can
be classified by single beam spectrophotometer, double beam spectrophotometer,
and double wavelength spectrophotometer according to the difference of optical
structure.
All kinds of UV/Vis spectrophotometer is composed of five basic component, they
are light source, monochrometer, cell holder, detector and signal processing
system.

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1.2.3 Condition of measure method
The choice of measuring wavelength
Normally taking the wavelength which has the most absorbance as the
measuring wavelength (
max

) to attain the highest analysis sensitivity is called
most absorbance principle. And the absorbance will change little along with
wavelength’s changing around the
max

, so we can get a better precision. But we
would like to take the low sensitivity measuring wavelength as the absorption
peak wavelength when measuring high concentration compounds, in order to
guarantee the corrective curve has enough linear range. If the absorption peak in
the wavelength
max

is too thin, we can adopt a little lower sensitivity wavelength
to measure on the condition that satisfies the need of analysis sensitivity, which is
to decrease the deviation of Beer’s Law.
The choice of absorbance range
Because of the unstable of light source, inaccuracy of reading, or alternation of
lab condition in the measurement, any photometer has some measuring error.
Because the transmittance T in the absorbance law is negative logarithm to the
concentration C, from the curve of negative logarithm we can see, the relative
error of the same transmittance in different concentration is different. The relative
error is very big when the concentration is too high or too low, so we should
choose the proper absorbance range to decrease the relative error of the result.
In practice, we can adjust the concentration of the solution or the length of the
cell to make the absorbance in the require range.
The choice of bandwidth
Bandwidth will affect the sensitivity of measurement and linear range of
correction curve. If the bandwidth is too wide, the monochromatic light of incidence
will be less, the correction curve will deviate from Beer’s Law, and the sensitivity
will be lower. If the bandwidth is too thin, the gain of the instrument will be very
high, the noise will be increase, and it’s not good for measurement. Measure the
deviation of absorbance along with the bandwidth so as to choose the proper one.
The absorbance will not change if the bandwidth is in a range, but the absorbance
will decrease if the bandwidth is as wide as some level. So the widest bandwidth
which is not decrease the absorbance is the proper one we should choose.

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1.3 Components description
When unpacking, the instrument is present as shown in Figure 1.1, next is the
detailed description of all components of the instrument.
Figure 1.1 Instrument overview
1.3.1 Front view
The front view is shown as Figure 1.2, the name and function of all
components is described below:
Figure 1.2 Front view
①Instrument cover
②Front baffle of sample compartment—standard front baffle for sample
compartment. It should be replaced when using some accessories.
③Chassis—the steel made chassis can greatly reduce vibration, and ensures
the credibility of the instrument.

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④Instrument label
⑤Sample compartment cover—Open the cover to gain access to the sample
compartment. The sample compartment is used to hold sample, it can be
replaced by manual 8-cell holder, long path length cell holder, and fixed cell
holder and so on.
1.3.2 Rear view
The rear view is shown as Figure 1.3, the name and function of all components
is described below:
Figure 1.3 Rear view
①Fan
②Foot packing—Shockproof rubber washer is used.
③RS-232 interface—Communicate with PC.
④Power supply—Connect to power supply: AC 220V, 50Hz.
⑤Fuse 1—Can be replaced (refer to “Appendix 3 fuse replacement”).
⑥Fuse 2—Can be replaced (refer to “Appendix 3 fuse replacement”).
⑦Instrument nameplate
1.3.3 Side view
The side view is shown as Figure 1.4, the name and function of all components
is described below:

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A Left side view B Right side view
Figure 1.4 Side view
①Power switch
②Light source house cover—Open the cover to gain access to the light source
house, where you can replace the deuterium lamp and tungsten lamp (refer
to “Appendix 1 light source replacement”).
1.3.4 Sample cell holder
The sample cell holder is configured according to the user’s requirements. The
general configurations are fixed cell holder, manual 8-cell holder, and long path
length cell holder. We can also provide you multiple kinds of sample cell holders
for your selection. Please refer to “chapter four Accessories” for the detailed
information.
The following figure 1.5 shows the fixed cell holder which is used as standard
configuration. This kind of sample cell holder is the most general structure, there
are two standard cell holders, and one is reference cell holder for blank sample,
while another is sample cell holder for measured sample.
Figure 1.5 Fixed cell holders

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1.4 Specifications
Figure 1-3
Model
Mega-900
Wavelength range
190nm ~ 90nm
Spectral bandwidth
Continuous slit 0.1 ~ 5.0 nm with 0.1 nm interval
Setting wavelength
The start and end wavelength can be set by the span
of 1nm. The goto-wavelength operation can be set by
the span of 0.1nm.
Wavelength accuracy
±0.3nm (with built-in automatic correction)
Wavelength
reproducibility
≤0.15 nm
Wavelength of
changing lamp
Set the wavelength of changing lamp within the
scope of 322-392nm at 1nm interval
Photometric system
Double beam, dynamic feedback direct ratio
recording system
Photometric scope
-4～4 Abs
Recording scope
Absorbance:-9.999～9.999 Abs
Transmittance:-999.9～999.9 %T
Photometric Accuracy
±0.3 %T (0~100%T)
Photometric
reproducibility
≤0.1 %T (0~100%T)
Stray light
≤0.01%T（220nm NaI）
≤0.05%T（340nm NaNO2）
Baseline flatness
±0.001 Abs ( scan with 850~200nm)
Stability
≤0.0004 Abs/h (2hr warm-up, kinetic scan at 500nm)
Noise
≤0.0004 Abs (500nm)
Note:
1. The above specifications are got at 2nm spectrum bandwidth. The specifications
are different at other spectrum bandwidths.
2. The above specifications are subject to change without notice.