721N Spectrophotometer Operating Manual
TABLE OF CONTENTS 1. APPLICATIONS AND FEATURES... 3 2. SPECIFICATIONS AND STANDARD ACCESSORIES... 4 3. PRODUCT APPEARANCE AND FUNCTION KEYS... 6 4. INSTALLATION... 9 4.1 INSTALLATION ENVIRONMENT... 9 4.2 CHECK-UP WHEN UNPACKING... 9 4.3 INSTALLATION... 10 5. OPERATIONS... 11 5.1 BASIC OPERATIONS... 11 5.1.1. Warming up... 11 5.1.2. Zero adjustment... 11 5.1.3. Adjust 100%T... 11 5.1.4. Wavelength measurement... 12 5.1.5. Change the groove position to get sample into optical path.... 12 5.1.6. Change the scales... 12 5.2 PRACTICAL OPERATIONS... 13 5.2.1. Measure the transmittance of transparent materials... 13 5.2.2. Determine the transmittance curves of transparent materials... 13 5.2.3 Determine the transmittance of transparent solutions... 14 5.2.4. Do quantitative measurement with standard curve method... 14 5.2.5. Use the direct reading... 15 6. MAINTENANCE AND ERROR RECOGNITION... 17 6.1 DAILY MAINTENANCE... 17 6.1.1 Notice... 17 6.1.2 Inspect the instrument... 17 6.1.3 Replace the source lamp... 17 6.1.4 Clean the liquid storage container... 18 1
6.2 CHECK THE FUNCTION OF MAIN DEVICE... 18 6.2.1 Check the wavelength range... 18 6.2.2 Check the transmittance repeatability... 18 6.2.3 Check fixed-point noise... 18 6.2.4 Check the wavelength repeatability... 19 6.3 IDENTIFYING AND HANDLING THE COMMON MALFUNCTIONS... 19 2
1. Applications and Features 721N visible spectrophotometer, compact and easy-to-use spectrophotometric equipment, can be used to measure transmission, absorption and concentration direct-reading at wavelengths from 360nm to 1000nm. It can be widely applied to departments related to medical health, clinical examination, biochemistry, petro-chemistry, environmental monitoring and quality control as qualitative and quantitative analyses. The main features are the following: 4-digit LED display Reasonable structure with advanced optical system, using precision machining high-quality CT monochromator and sealed grating, the optical properties of which are superior to the traditional LITTROW monochromator, with obvious advantages in the indicators such as resolution, photometric accuracy, stray light and stability. And its size is smaller. Special precision pre-adjustment lamps and lamp holder fittings. Not necessary to re-adjust optical path for installation which is convenient for users without any professional maintenance skills. Precision-linkage cutoff filter system automatically switching to appropriate wavelength filters, further reducing stray light Sample cells made of special engineering plastics, resistant to solvent as well as strong acid/alkali, which enhances its anti-corrosion properties. Effusion dish and liquid storage container, which can be removed and cleaned, are mounted on the bottom to increase the service life. 4-position colorimetric cell shelf, with optional rectangular optical path colorimetric dish with diameter from 1 cm to 5cm. Automatic zero and 100%T adjustment Concentration factor setting and concentration direct-reading functions 3
2. Specifications and Standard Accessories 1. Optical system: diffraction grating C-T monochromator 2. Wavelength range:360nm~1000nm 3. Source lamp: halogen lamp 10W/8V 4. Wavelength accuracy: ±3.0nm 5. Wavelength repeatability: 1.5nm 6. Transmittance accuracy: ±0.8 %( ) (SRM930D) 7. Transmittance repeatability: 0.3 %( ) 8. Spectrum bandwidth: 6nm 9. Stray light: 1.0 %( ) (360nm, NaNO 2 ) 10. Display scale: (T):0.0~199.9% (A):-0.3~2.999 (F):1~9999 (C):0~9999 11. Power supply: 90~250V, 50/60Hz, 40W 12. Dimension: 350mm 300mm 220mm 13. Weight: net weight: 4kg; gross weight: 6kg 14. Basic set: 1. Main device: 1pc 2. Power cord: 1pc 3. Operating manual: 1pc 4. Product Quality Certificate: 1pc 5. Fuse (2A): 2pcs 6. 1cm rectangular colorimetric dish (glass): 4pcs 7. 1cm optical path colorimetric dish shelf: 1pc 8. Packing list: 1pc 15. Optional spare parts 1. Fuse (2A/3A) 2. Illuminant light components with pre-calibration lamp bracket 4
3. Rectangular colorimetric dish: 1cm, 2cm, 3cm, 5cm 4. 5cm optical path colorimetric dish shelf 5. Pr-Nd filters 6. Holmium trioxide filters 5
3. Product Appearance and Function Keys 1. /100% key: automatically adjusts 100%T when "transmittance lamp is bright (Press once again if the first press doesn't work); automatically adjusts absorbance 0 when "absorbance lamp lights (press once again if the first press doesn't work); increases concentration factor settings when "concentration factor lamp is bright. Press for 1 second, then the values increase rapidly, then press MODE to confirm set values automatically; increases concentration direct-reading settings when "direct-reading lamp lights. Press for one second, the values increase rapidly, and then press MODE to confirm set values automatically. 2. /0% key: automatically adjusts 100%T (range<10%t) when "transmittance lamp lights; *Don't use "absorbance" lamp when it is bright, otherwise it ll be overloaded; reduces concentration factor settings in the same way as for /100% when "concentration factor lamp lights reduces direct-reading settings in the same way as for /100% when "direct-reading method lamp lights. 3. FUNCTION key: is used as an extension functional key for presetting 4. MODE key: selects display scales 6
lamps lights up in the sequence of "transmittance, "absorbance, "concentration factor, and "direct-reading, press to start another circle of lightening lamps. 5. Display window 4-digit LED number Displays data and error information 6. "Transmittance lamp: displays transmittance data 7. "Absorbance lamp displays absorbance data 8. "Concentration factor lamp: displays concentration factor data 9. "Concentration direct-reading lamp: displays direct-reading data 10. Sample cell: tests samples 11. The pull rod of the groove shelf: changes the position of sample groove (4) 12. Wavelength display window: displays the wavelength 13. Wavelength regulation button: adjusts the wavelength 14. Power socket: connects the power cord 15. Main switch: ON/OFF power supply 7
6 7 8 9 5 4 3 2 1 10 11 12 13 14 15 8
4. Installation 4.1 Installation environment This instrument is suitable for analytical experiments under lab conditions, the following requirements are demanded due to the fact that it works with PC: 4.1.1 Temperature: 5 ~35, relative humidity is less than 85%. 4.1.2 It is mounted on a steady working platform, free from vibration, direct sunlight, strong electromagnetic field interference, dust and corrosive gas. 4.1.3 Power voltage:90~250v Frequency:50/60Hz 4.1.4 Clean the instrument surface with room temperature water, do not use cleaning solvents such as alcohol or acetone 4.1.5 If the equipment is to be used on the spot, please use the original package while being moved. On-site working environment usually complies with the above requirements. Please make special orders if users have special requirements. 4.2 Check-up when unpacking 4.2.1 Note: the instrument and computer are packed in paper cardboard boxes (wooden boxes are required for long-distance transportation). 4.2.2 Please check the package before unpacking. If the package is incomplete or Collision traces are found, please contact the insurance and transportation department. 4.2.3 Open along the sealing tapes; carefully remove the main device and computer (please save the outer package for the later using). Check the main device's Standard and optional components according to the packing list. Contact the area sales or our company if there is any problem. 9
4.3 Installation 4.3.1 Remove the fixing tapes which are for transportation, clean the surface, then check the power switch at the bottom of the device. Make sure voltage requirement is consist with the local power supply, then put the main device on a stable working station, keeping clearance more than 10 cm away from the wall. Connect power cord to the outlet at the lab. 10
5. Operations 5.1 Basic operations 5.1.1. Warming up After the instrument is started, lamps and electric components need heat balance; therefore, measurement will be done in 30 minutes after it is warming up. For urgent usage, adjust 0%T or 100% any time. 5.1.2. Zero adjustment Purpose: adjusts both sides of the basic scale (along with 100%T adjustment), enter the correct testing module; Timing adjustment: after warming up, change measuring wavelength or having tested for a period; or before high precision measurement; Operation: open the sample cover (automatically shut the light valve) or shade the optical path with opaque materials in the sample cell, then press 0%, then zero is automatically adjusted. 5.1.3. Adjust 100%T Purpose: adjusts both sides of the basic scale (along with zero adjustment), and enters the correct measuring status; Timing adjustment: after warming up, change measuring wavelength or testing for a period or before high precision measuring (generally, do 100%T adjustment before zero adjustment as to make the automatic increase inside the device to the full reach); Operating: empty sample used as background is put into the light valve of the sample cell, shut the sample cover (automatically open the light valve), press 100% to automatically adjust 100%T (press once more if error occurs); Note: when adjusting 100%T, the automatic gain system re-adjustment may 11
influence 0%T. Check 0%T after adjustment. If there's any change, re-adjust 0% for once. 5.1.4. Wavelength measurement Use the only knob on the equipment to adjust the current measuring wavelength. The wavelength displays on the window to the left of the knob. Read the readings vertically. Note: this machine uses precision-linkage cutoff filters system, so when the knob rotates, there will be metal gratings. Low gratings at 360nm-1000nm are normal. 5.1.5. Change the groove position to get various samples into optical path. In the standard specification, the testing sample groove shelf has four positions. It can be controlled by the pull rod on the front of the device. Open the sample cell cover to observe the positions: the closest one to the user is 0, then 1, 2, 3 in sequence. The corresponding pull rod reaches 0 by pushing backward to the end, then pull 1, 2, 3 outward respectively. When the rod is at the right position, the user may feel it. Please push it a bit to make sure the position is right. 5.1.6. Change the scales This equipment has four scales: Transmittance: measures the transmittance features of transparent liquids and solids; Absorbance: uses as quantitative analysis with standard curve method or absolute absorption spectrometry; also used in kinetic tests; Concentration factors: sets concentration factors when direct reading with the concentration factor method; Concentration direct-reading: sets and reads with standard sample method to read directly; also directly reads the concentration when setting concentration factors; 12
Use MODE to adjust the scales, which displays with the lamps for transmittance, absorbance, concentration factor, direct-reading respectively, the initial status is transmittance, press to select by following the above procedures. 5.2 Practical operations 5.2.1. Measure the transmittance of transparent materials Warm up 5.1.1 1 Set wavelength 5.1.4 2 Set the blank 5.1.5 3 Set the scale to "transmittance 5.1.6 4 Adjust 100%T 5.1.3 5 Adjust zero 5.1.2 6 Adjust 100%T 5.1.3 7 Add samples 5.1.5 8 Read data 5.2.2. Determine the transmittance curves of transparent materials Within the required wavelength to be measured, repeatedly execute this method according to the required intervals in phase 1-8 of section 5.2.1, and write down the responding transmittance values on the paper, to display the transmittance curves. 13
5.2.3 Determine the transmittance of transparent solutions Warm up 5.1.1 1 Set wavelength 5.1.4 2 Set the blank 5.1.5 3 Adjust 100%T 0%T 5.2.1 5-7 4 Set the scale to absorbance 5.1.6 5 Add the sample in the optical path 5.1.5 6 Read data 5.2.4. Do quantitative measurement with standard curve method 1 Get standard samples with known content 2 Prepare sample solutions and background solutions due to rules of analysis 3 Set wavelengths, blanks, zero adjustment, "absorbance", and read sample absorbance 5.2.3 1-6 4 Repeat the above procedures and read the samples' absorbance 5.2.3 2-6 5 Read the absorbance, draw the coordinate maps based on samples' known contents, and draw the best relative curves 6 Read the unknown samples' absorbance, and find 5.2.4-3 14
responding concentration on the curve 5.2.5. Use the direct reading When the analysis procedure is stable and the basic standard curve passes the original point, users apply direct-reading to do quantitative measurement instead of through complex standard procedures. This method needs to prepare one sample solution with concentration at 2/3 of the quantitative range. The operation is as follows: 1 Measure the absorbance of standard samples 5.2.4 phase 1-3 2 Set the scale at concentration direct-reading 5.1.6 3 Press or to set the reading at the known content(or 10 times of contents) 4 Add unknown sample solutions 5.1.5 5 Read the displaying data, i.e. The content value(or 10 times of contents) 5.2.6. Use concentration factors directly After the 3rd procedure, if the scale is set at concentration factor, the reading in the display window is the sample's concentration factor. Record the factor, then users read the figure without measuring it again until is switched off. The procedure is as follows: 1 Switch on, warm up, set the wavelength, set the background solution, adjust 0% and 100%T 2 Set the scale at concentration factor 5.1.6 3 Press or to make the display value is the factor value 4 Set the scale at concentration direct-reading 5.1.6 5 Set unknown sample solution 5.1.5 15
6 Read the displaying value, i.e. the concentration value 16
6. Maintenance and error recognition 6.1 Daily maintenance 6.1.1 Notice 6.1.1.1 Comply with requirements in 4.1 for daily use; 6.1.1.2 Do not use organic solvents such as ethanol-ether to clean the equipment. Use a cover when it's not used; 6.1.1.3 Clean the colorimetric dish with petroleum ether after using, and dry it with lens paper, is kept colorimetric dish box for the next use. 6.1.2 Inspect the instrument It is necessary to open the cover when it is required to check up the device, including the inner structures, optical path, and electric circuit, or to replace the source lamp. The procedures are as follows: 6.1.2.1 Power off; 6.1.2.2 Open the wavelength knob cover and remove the knob; 6.1.2.3 Remove five M4 screws from the bottom of the equipment, open the cover to check the equipment (avoid touch the high-voltage part on the back of the device base). 6.1.3 Replace the source lamp The equipment uses the long-service combining source lamp pre-corrected by the factory. Replace the damaged lamps based on the following steps: 6.1.3.1 Open the upper cover (see 6.1.2); 6.1.3.2 Remove the old illuminant light's parts: remove the connecting cable, 2 M4 screws on the lamp shelf, and other parts; 6.1.3.3 6.1.3.3 Re-install the new illuminant parts according to the reverse order as that in 6.1.3.2; observe the reflector at front, adjust the position of 17
the parts, and make sure the rectangle spots in the middle of the incident slit. 6.1.4 Clean the liquid storage container 6.1.4.1 Lift the equipment up a little, and move the front end out of the desk; 6.1.4.2 Take out the container on the bottom (beware of liquids flowing out during this procedure); 6.1.4.3 Dump the liquid, clean the container with water and dry it; 6.1.4.4 Mount the container back to the original place; 6.1.4.5 Put the equipment back to the original place. 6.2 Check the function of main device After the equipment finishes testing and maintenance, use the following to check to make sure the equipment has the standards. 6.2.1 Check the wavelength range 6.2.1.1 Switch on the host and pre-heat for 30 min, the mode is on transmittance ; 6.2.1.2 Turn the wavelength knob to both sides of the wavelength range, press 100%, 100%T will be achieved. Open the sample cell door, 0% can adjust to 0%T. 6.2.2 Check the transmittance repeatability 6.2.2.1 Set the host's wavelength to 550nm, equipment to 0%T and 100%T. 6.2.2.2 Set the transmittance to 40%T and check the display value around the samples which are evenly absorbed nearby successively for three times (i.e. neutral filters). The maximal difference should be between±0.3%t. 6.2.3 Check fixed-point noise 6.2.3.1 Set the wavelength to 550nm, and adjust to 0%T and 100%T. 18
6.2.3.2 Set the scale to absorbance. 6.2.3.3 Observe the data in the window, which should be within the range of 0.002A. 6.2.4 Check the wavelength repeatability 6.2.4.1 Set the scale to transmittance. 6.2.4.2 Use the (Pr-Nd) filters (optional accessories, provided by ordinary companies) as samples. 6.2.4.3 Regard air as blank, adjust the equipment to 0%T and 100%T, add the sample into the optical path, read the responding wavelength values to standard peak value among 520nm~540nm. 6.2.4.4 Repeat 6.2.4.3 three times, the wavelength reading errors should be 1.5nm. 6.3 Identifying and handling the common malfunctions Malfunctions Causes solutions 1) The equipment is powered on, but is not on 2) Instable data display 1. Not connected to the power 2. Fuses broken 3. Connectors loose 1. Not enough pre-heating time 2. Unstable AC power 3. Drastic vibration around the working environment 4. Bad plug-in connections 1. A Check the plug, should be well connected between 90~250V B Check if the power cable breaks C Check if the power plug breaks 2. Replace fuses 3. Re-plug plug-ins 1. Warm up for 30 mins 2. Maintain the power at 90~ 250V without sudden change 3. Change working environment 4. Open the cover and re-plug all plug-ins 19
3) Energy not 1. Illuminant light not light 1. Broken illuminant light to be measured 2. The light valve not open changed, or no voltage output 3. The colorimetric ware 2. Check if the light valve works completely cover the light 4. No signal output 3. Put in at the right position 4. Receiver broken to be changed, or not plugged in, or back contact 4) Cannot adjust 1. Not enough light energy 1. Select the right gain key; to 100%T 2. Colorimetric dish not in position check the light from the illuminant light in the incident slit; low light voltage adjust higher 2. Adjust it to the right position 5) Abnormal 1. Wrong solutions to the 1. Dealt with properly photometry samples 2. Reduce matching errors 2. Colorimetric dish not 3. Check with (Pr-Nd) glass and match adjust wavelength 3. Big wavelength errors 6) Err3 displays 1. Wrong operation 1. Power off then on again 20