Hydrogen Microsensor Manual
Contents
1. 988 57968 71 206 98 16 9v 676 OL S0 ZIZ 89 6L 9LL LUS8L 79 762 9 508 96 918 9v 6c8 SL Ev8 6 858 Sy S 8 0 68 S6 TL6 99 ET6 88Y56 t5 5y6 65 156 79 696 65786 0 8c oc vc Te oz 8L 9L vL cL e 2 O N m 1 1 o Do dW3 21 22 UNISENSE UNISENSE DENMARK www unisense com info unisense com2. for 30 seconds After this period switch the polarization back to 1000 mV Repeat calibration procedures when the signal is stable again High and drifting signal The sensor tip is broken Replace the hydrogen microsensor The signal is very low Loss of the platinum tip due to excessive vibrations Replace the hydrogen microsensor Slow response Insoluble compounds deposited at the sensor tip Rinse with 96 ethanol rinse with 0 01 M HCI and rinse with water 19 TROUBLE SHOOTING Problem Possible cause Solution Problem Possible cause Solution Slow response The sensor might have lost hydrogen sensitivity temporarily Expose the sensor to high partial pressures of hydrogen gt 10 atm for at least 10 minutes to reactivate the sensor Unstable signal or the signal fluctuates if the set up is touched or equipment is being introduced in the medium you are measuring in Electrical disturbance of the sensor through the tip membrane Ground the set up using the blue grounding cable supplied with the picoammeter Connect the reference plug on the picoammeter blue plug with the medium you are measuring in If you encounter other problems and need scientific technical assistance please contact sales unisense com for online support we will answer you within one workday 20 Table 1 Equilibrium hydrogen concentrations umol litre at ambient hydrogen partial pressure of 1 atm in wat
3. method is to rinse with 96 ethanol NOT in the protection tube then rinse with 0 01 M HCl and rinse with water This will remove most substances Alternatively it is possible to rinse with 0 1M NaOH isopropanol or different detergent 17 REFERENCES e Revsbech N P and B Jorgensen 1986 Microelectrodes Their Use in Microbial Ecology p 293 352 In K Marshall ed Advances in Microbial Ecology vol 9 Plenum New York e Itoh T et al 2009 Molecular Hydrogen Suppresses FcepsilonRI Mediated Signal Transduction and Prevents Degranulation of Mast Cells Biochem Biophys Res Commun 389 651 656 Kajiya M et al 2009 Hydrogen From Intestinal Bacteria Is Protective for Concanavalin A Induced Hepatitis Biochemical and Biophysical Research Communications 386 316 321 Kajiya M et al 2009 Hydrogen Mediates Suppression of Colon Inflammation Induced by Dextran Sodium Sulfate Biochemical and Biophysical Research Communications 386 11 15 Vopel K et al 2008 Modification of Sediment Water Solute Exchange by Sediment Capping Materials Effects on O2 and PH Marine and Freshwater Research 59 1101 1110 TROUBLE SHOOTING Problem Possible cause Solution Problem Possible cause Solution Problem Possible cause Solution Problem Possible cause Solution Decreasing sensitivity Contamination of the anode surface e g by sulfide Switch the polarization to 1000 mV
4. This signal is your calibration value for zero hydrogen conditions HYDROGEN READING The hydrogen sensor responds linearly and conseguently a two point calibration is sufficient Prepare a water phase with a defined hydrogen concentration which is slightly above the maximum expected hydrogen to be measured A defined hydrogen concentration can be obtained by 2 different procedures 1 Use gas mixture controller to obtain a defined mixture of hydrogen and hydrogen free inert gas from a gas tank e g as bulk carrier gas For instance to obtain a hydrogen concentration of 10 uM in the calibration chamber at 20 C bubble the water in the calibration chamber vigorously with a gas mixture containing 98 77 N and 1 23 hydrogen partial pressure 0 0123 atm solubility 813 umol liter atm 10 umol liter see Table 1 For a Unisense 250 ml calibration chamber 5 minutes of bubbling at a rate of 5 per minute is sufficient time to achieve 99 of the concentration If the IMPORTANT Hydrogen sensors are sensitive to temperature and salinitv IMPORTANT Calibration must be performed after pre polarization when the sensor signal has stabilized Always use a calibration solution with the same temperature and salinity as the sample solution 11 equipment gas mixture controller is available this method can be convenient as you can switch between different constant hydrogen conditions without changing the w
5. Vh UNISENSE HYDROGEN SENSOR USER MANUAL HYDROGEN SENSOR USER MANUAL Copyright 2014 Unisense A S Version January 2014 HYDROGEN SENSOR USER MANUAL UNISENSE A S TABLE OF CONTENTS SUPPORT ORDERING AND CONTACT INFORMATION OVERVIEW ea GETTING STARTED nassen UNPACKING A NEW SENSOR POLARIZATION CONNECTING THE MICROSENSOR PRE POLARIZATION CALIBRATION Hydrogen reading MEASUREMENTS 2 tadas MOUNTING OF THE SENSORS ELECTRICAL NOISE INTERFERENCE ADVANCED USE u aaa rra oia STORAGE AND CLEANING THE SENSOR REFERENCES dara data TROUBLE SHOOTING abre rob ER bab Ee it WARRANTY AND LIABILITY NOTICE TO PURCHASER This product is for research use only Not for use in human diagnostic or therapeutic procedures WARNING Microsensors have very pointed tips and must be handled with care to avoid personal injury and only by trained personnel Unisense A S recommends users to attend instruction courses to ensure proper use of the products WARRANTY AND LIABILITY The Hydrogen sensor is covered by a 90 days limited warranty Microsensors are a consumable Unisense will only replace dysfunctional sensors if they have been tested according with the instructions in the manual within 14 days of receipt of the sensor s The warranty does not include repair or replacement necessitated by accident neglect misuse unauthorized
6. ater Use the solubility table Table 1 to find the correct mixture at temperatures other than 20 C To obtain correct concentrations the headspace above the water in the calibration chamber must be closed except for a hole only slightly larger than the microsensor shaft This effectively prevents ambient air from entering the vessel We recommend the Unisense Calibration Chamber for calibrations Add a defined volume of hydrogen saturated water to a defined volume of water in a calibration chamber For instance 1 ml of H saturated water contains 0 805 hmol at 20 C see Table 1 and to obtain water with a hydrogen concentration of 10 uM 3 08 ml hydrogen saturated water should be added to a total volume of 246 9 ml hydrogen free water in the calibration chamber After the addition of hydrogen saturated water to the calibration chamber mix it thoroughly by moving the sensor in its protection tube up and down for a few seconds and read the signal when it is stable Do not stir bubbles into the water or mix by bubbling as this will remove hydrogen from the water A magnetic stirrer is not recommended as a mixing tool as a magnetic stirring can introduce electrical noise to the signal The hydrogen in the water will slowly escape to the atmosphere Calibration chamber CAL300 WARNING Vigorous bubbling water with any gas may cause the water to cool considerably Monitor the temperature to find a suitable bubbling rate w
7. ements done in environments with high sulfide concentrations are not recommended 15 ADVANCED USE Unisense can construct hydrogen sensors for customer requested applications at additional costs The most frequently requested construction options are described at our web page The options include for instance customer specified dimensions response time stirring sensitivity pressure tolerance range and detection limit If your specifications for a special hydrogen sensor is not described at our web page please contact sales unisense com for further options and prices Examples of advanced applications Consumption production rates of hydrogen E g during enzyme assays in small samples in Unisense microrespiration chambers MRCh Measurements of hydrogen under high external pressure e g in closed pressurized systems underwater and deep sea applications Long term hydrogen monitoring If you have questions please contact salesaunisense com STORAGE AND MAINTENANCE Store the sensor in the protective plastic tube used for shipping The hydrogen microsensor can be stored with the tip exposed to water or air The room in which the hydrogen microsensor is stored should be dry and not too hot 10 30 C If the sensor is used regularly it can be stored polarized CLEANING THE SENSOR Depending on which substance is present on the sensor tip or membrane the sensor can be cleaned with different solutes The standard
8. ense com Unisense A S Tueager 1 DK 8200 Aarhus N Denmark Tel 45 8944 9500 Fax 45 8944 9549 Further documentation and support is available at our website www unisense com REPLACEMENT OF SENSORS Unisense will replace sensors that have been damaged during shipment provided that The sensors were tested immediately upon receipt in accordance with the delivery note and the manual The seal is still intact The sensors are returned to Unisense for inspection within two weeks The sensors are correctly packed for return to Unisense in accordance with the note included in the sensor box RECOMMENDED AMPLIFIERS One channel amplifier Microsensor Monometer Multi channel amplifiers Microsensor Multimeter OVERVIEW The Unisense hydrogen microsensor is designed for research applications within physiology biotechnology environmental sci ences and related areas With the minute tip size excellent response time and good sen sitivity the Unisense hydrogen sensor facilitates reliable and fast measurements with a high spatial resolution The Unisense hydrogen microsensor is a miniaturized Clark type hydrogen sensor with an internal reference electrode and a sensing anode The sensor must be connected to a high sensitivity picoammeter where the anode is polarized against the internal reference Driven by the external partial pressure hydrogen from the environment will pass through the sensor tip membrane and wi
9. er as a function of temperature Ref Wiesenburg and Guinasso 1979 J Chem Eng Data 24 4 356 360 96 119 88 979 62 159 65 159 67 799 149 T0 6 9 05 89 57969 0 90 9t 6Z 96 12 99 8h 08 5S 6 59 86 0 LS 8LL 0 8 7S S6L 97 708 or TE LY9 ET TSI 65 159 78 599 60 0 9 0119 LCS89 SL E69 EL EOZ GE ELZ 55 ZL 19 95 65 67 OL 9SL 78 59 571 ZO 6LL 05182 86 562 97 708 v8 18 8 EL ESI 70 859 6 99 79 699 vE 9L9 8b 89 75 169 St 00 12014 vS 07L OL LEZ OC vv 65 151 EL v9L 88 14Z 16 6 05 8 86 S6Z 9t v08 78 518 LT ET8 9 87 859 78 599 07 699 Sy S 9 71 789 689 1Z 869 7 96 91L 89 T 6T 6E 6L 1SZ E9 S9L LL TLL 9 08 56 8 v 96 16 708 v8 EL8 LLCC8 6S TEB vt 6C v99 79 699 00 529 07 189 6 889 86 569 9v v0 v8 ElZ 99 ET 78 VEL 374174 8E 6S 99 ELL 08 08 6 88L v 96 16 708 78 518 608 vl TE8 96 1v8 TE 60 0 9 Sy G 9 ST 189 05 789 79 769 89 T0 OL LLZ vS 07L 08 0 96 1b 0 17 291 0 18 6T 68 88 96 9 S08 78 518 LLTT8 vl TE8 Z9 ty8 6 158 0 uad s1uvd ALINIIVS SS 669 L6 vOL L9 LLZ SL 8LZ vE 97L LUSEL vO vbL gE SSZ 75 992 0 6 17 762 71 208 1T ET8 0 158 81078 SS 6v8 6 858 07 698 9v 6 8 81 068 1E 106 oc 16 67 OL 9EZ 0E Eh HELS T8 6S 79 692 16 621 CS 16Z Z0Y08 98 18 v0 E 8 LL 678 96 998 79 8 91
10. for both internal reference elec trode and sensing anode PRE POLARIZATION Just after connecting the sensor the signal will be very high and unstable then drop rapidly over the first few minutes After that the signal will drop slowly for up to 1 hour Therefore a period of polarization is necessary before you can use the sensor This is called the pre polarization period The signal should stabilize at 0 50 picoampere on the PA2000 the sign will be negative since sensor is positively polarized for zero hydrogen concentration depending on the specific sensor If the sensor is new or has not been operated for several days it WARNING Do not remove the seal and protective plastic tube before these steps and calibration are succesfully completed WARNING Incorrect polarization may destrov the sensor 5nid O31 must be polarized for at least 1 hour before it can be calibrated and used After shorter periods without polarization the sensor should be polarized until it has exhibited a stable signal for 10 minutes The signal depends on the specific sensor see the value in the specifications that came with the sensor If the signal does not stabilize or is too high or too low refer to the Trouble shooting section of this manual CALIBRATION Calibration must be performed after the sensor signal has stabilized during pre polarization ZERO HYDROGEN READING Place keep the sensor tip in water and read the signal
11. hich does not cool the water significantly and the concentration can only be considered constant for a few minutes Hydrogen sensors respond linearly in the range of 0 to 100 hydrogen and signals can be linearly converted to partial pressure Check and repeat calibration at appropriate intervals to ensure that all measurements can be calibrated to correct concentrations When the sensor is new the appropriate interval may be every 30 minutes later it may be 24 hours minimize the need for calibrations keep the sensor polarized between measurements unless the time between measurements exceeds several days or unless the picoammeter batteries are running out The membrane permeability of hydrogen microsensors changes with time so a change in signal of up to 50 may occur over months If the sensor functions according to the above procedure the seal and protective plastic tube can be carefully removed before making measurements 13 MEASUREMENTS Hydrogen sensors can be used for a wide variety of measurements see our web page for further information www unisense com The most common use of hydrogen sensors is for making profiles in e g sediment or animal tissue where a high spatial resolution is wanted or for hydrogen measurements in water samples MOUNTING OF THE SENSORS Although the Unisense microsensors are made of glass the tip is flexible and can bend slightly around physical obstacles The sensor is th
12. ll be oxidized at the platinum anode surface The picoammeter converts the resulting oxidation current to a signal IMPORTANT Unisense sensors are neither intended nor approved for use in humans THIS MANUAL COVERS THE UNI SENSE HYDROGEN MICROSENSORS H 10 tip diameter lt 20 um 25 tip diameter 20 30um H 50 tip diameter 40 60um H 100 tip diameter 90 110um dmn 10su9S 5nid Owa H 500 tip diameter 500um H MR for use with microrespiration chambers MR Ch H N Needle type sensor Customer specified Schematic view of a hydrogen sensor with a LEMO plug GETTING STARTED UNPACKING A NEW SENSOR When receiving a new microsensor remove the shock absorbing grey plastic net POLARIZATION The signal from the hydrogen sensor is generated in picoampere Therefore the hydrogen sensor must be connected to a polarizing picoammeter e g a Microsensor Monometer a Microsensor Multi meter or the Unisense PA2000 Hydrogen sensors should be polarized at 1000 mV The polariza tion voltage is set in the amplifier For details on how to set and check the polarization consult the user manual of the picoamme ter to be used If you are using a PA2000 amplifier please check the polarization voltage before connecting the sensor since incorrect polarization may destroy the sensor CONNECTING THE MICROSENSOR Connect the LEMO connector to the input terminal The LEMO connector contains connections
13. repair or modification of the product In no event will Unisense A S be liable for any direct indirect consequential or incidental damages including lost profits or for any claim by any third party arising out of the use the results of use or the inability to use this product Unisense mechanical and electronic laboratory instruments must only be used under normal laboratory conditions in a dry and clean environment Unisense assumes no liability for damages on laboratory instruments due to unintended field use or exposure to dust humidity or corrosive environments REPAIR OR ADJUSTMENT Sensors and electrodes cannot be repaired Eguipment that is not covered by the warranty will if possible be repaired by Unisense A S with appropriate charges paid by the customer In case of return of eguipment please contact us for return authorization For further information please see the document General Terms of Sale and Delivery of Unisense A S as well as the manuals for the respective products CONGRATULATIONS WITH YOUR NEW PRODUCT SUPPORT ORDERING AND CONTACT INFORMATION The Hydrogen microsensor is a miniturized sensor for measuring partial pressure of H in the micromolar range If you wish to order additional products or if you encounter any problems and need scientific technical assistance please do not hesitate to contact our sales and support team We will respond to your inguiry within one working day E mail salesaunis
14. us rather sturdy in the longitudinal direction However large obstacles like stones or lateral movements of the sensor when the tip is in contact with a solid substrate may cause the tip to break Furthermore due to the small size of the microsensor tip and to the steepness of gradients in many environments even a displacement of the sensor tip of few microns may change its environment Therefore we recommend that measurements should be performed only in a stabilized set up free of moving or vibrating devices We recommend the Unisense lab stand LS18 and the Unisense micromanipulator MM33 MM33 2 or MMS for laboratory use For in situ use we recommend our in situ stand IS19 and a micromanipulator Micromanipulator ELECTRICAL NOISE The signal of the microsensor is very small 10 to 10 ampere Although both the Unisense picoammeters and the Unisense Hydrogen microsensors are very resistant to electrical noise from the environment electrical fields may interfere with the sensor signal Therefore we recommend that unnecessary electrical mechanical equipment is switched off and the sensor or wires are not touched during measurements and signal recording INTERFERENCE The presence of sulphide gas can affect measurements The sensitivity to sulfide gas can be as much as 10 of the hydrogen sensitivity In addition exposure to high sulfide gas concentration can affect the calibration of the hydrogen sensor Therefore measur
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