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Antec Leyden 120.0035 Скачать руководство пользователя страница 62

CHAPTER 7 Optimisation of working potential

59

C H A P T E R 7

Optimisation of working potential

Introduction

A current - voltage (I/E) relationship, or voltammogram, characterises an
analyte. It gives information on the optimum working potential, which can be
used to improve detection sensitivity and selectivity.
There are several ways to obtain a voltammogram. A

hydrodynamic

voltammogram is obtained in the DC mode by running several
chromatograms at different working potentials. Both peak height and
background current are plotted against the working potential. A

scanning

voltammogram is obtained in the so-called scan mode of the DECADE: the
voltage runs between two pre-set values and the current is measured.
Optimisation of the working potential and the construction of a voltammogram
is described.

Electrochemical reactions

In electrochemical detection (ECD) a reaction of the analyte at an electrode
surface is monitored. This distinguishes ECD from most other detection
techniques where detection is based on the physical properties of an analyte
(i.e. mass spectrometry: molecular mass, absorbance detection: molar
absorptivity). For electrochemically active compounds, the potential between
reference electrode (REF) and working electrode (WE) determines the
reactivity of the analyte at the WE. The potential difference supplies the
energy level needed to initiate or enhance the electrochemical reaction.
Different analytes may have different oxidation or reduction potentials, which
determines the selectivity of ECD.

Fig. 22. Oxidation/reduction reaction of nor epinephrine.

An example of an electrochemical reaction is shown in Fig. 22, nor
epinephrine is converted into a quinone by oxidation at the WE. Two

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Содержание 120.0035

Страница 1: ...excess underutilized and idle equipment along with credit for buybacks and trade ins Custom engineering so your equipment works exactly as you specify Critical and expedited services Leasing Rentals Demos In stock Ready to ship TAR certified secure asset solutions Expert team I Trust guarantee I 100 satisfaction All trademarks brand names and brands appearing herein are the property of their respe...

Страница 2: ...Edition 9 2007 120 0010 DECADE Digital Electrochemical Amperometric Detector user manual Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 3: ...Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 4: ...y IEC 801 2 3 4 ENV 50140 Radio frequency current injection ENV 50141 IEC 1000 4 6 Voltage dips and interruptions IEC 1000 4 11 Emissions 89 336 EEC Electromagnetic radiation EN 55022 Class B CISPR 22 Attention Use shielded cable s to connect all I O s with other devices Thoroughly connect the shielding to common Antec Leyden will not accept any liability for damage direct or indirect caused by co...

Страница 5: ...ec Leyden the Netherlands at the end of life time of the product The manufacturer will take care of the proper disposal and recycling of the instrument at its facilities Shipping address for the end of life products Antec Leyden Industrieweg 12 2382NV Zoeterwoude The Netherlands In case of questions or if further information is required about the collection recycling procedure please contact your ...

Страница 6: ...he manual for further safety instructions Frame or chassis ground terminal The following pictograms are used in the DECADE II manual Caution Caution risk of electric shock or other electrical hazard high voltage Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 7: ...wn fuses with fuses of proper type and rating as stipulated on the rear panel and specified in the installation section of this manual The fuse holder is integrated in the mains connector Ensure that the instrument is never put in operation with fuses of a different type This could cause fire USE ONLY WITH 250 V FUSES EMPLOYER UNIQUEMENT AVEC DES FUSIBLES DE 250V Connect the detector to a grounded...

Страница 8: ...ive years after shipment of the final production run of the instrument Spare parts will be available after this five years period on an as available basis Manufacturer provides a variety of services to support her customers after warranty expiration Repair service can be provided on a time and material basis Contact your local supplier for servicing Technical support and training can be provided b...

Страница 9: ...6 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 10: ...9 Overview of all DECADE screens 20 Parameters 22 Data acquisition 29 Introduction 29 Internal organisation 29 Integrator output 30 Recorder output 31 Integrator vs recorder output 33 Offset 34 AUTO mode and time files 37 Introduction 37 Range programming 37 Drift monitor 38 Step by step example DECADE Master 39 Hardware connections 39 Programming the AUTO mode 40 Important note when using the dri...

Страница 11: ...54 Peak width and integrator frequency 55 Working electrode material 56 References 58 Optimisation of working potential 59 Introduction 59 Electrochemical reactions 59 Hydrodynamic and scanning voltammogram 60 Optimisation using a voltammogram 62 Construction of a hydrodynamic voltammogram 64 Construction of a scanning voltammogram 64 Specifications DECADE 67 General specifications 67 DC mode 67 P...

Страница 12: ...ctor response 73 High cell current 73 Noisy baseline 73 Decreased sensitivity low S N ratio 73 Baseline oscillations 74 Saturation of output 74 Pulse damper 75 Dummy cell 76 Index 77 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 13: ...10 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 14: ... DECADE an electrically actuated option injector and a high efficiency pulse damper can be incorporated in the oven compartment The DECADE covers the DC pulse and scan mode Important parameters in the DC and pulse mode can be changed on a time base by user defined commands which enables maximum control to fully automate the detection In addition crucial settings start stop hold auto zero cell on o...

Страница 15: ...12 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 16: ...sible performance The results of the electronic tests are included in the shipkit Installation Please follow the next steps for a successful installation and start up 1 To unpack the DECADE lift it from its transport box by both hands as indicated in Fig 1A In any other situation the DECADE should be lifted by both hands under the unit as indicated in Fig 1B Fig 1 Lift instructions DECADE 2 Inspec...

Страница 17: ... option and pulse damper option is schematically shown in Fig 2 5 If ordered install the pulse damper Connect the mounting plate with the four bolts supplied to the pulse damper and mount the pulse damper with four bolts For detailed instructions on the pulse damper see page 75 6 If ordered the Antec supplied injection valve is equipped with a Vespel rotor as a standard For use of strongly alkalin...

Страница 18: ...artment is not flooded For proper function of the drain the detector must be placed level 10 Prior to connection of the HPLC system to the detector all metal parts should preferably be passivated with 15 nitric acid during 20 min Make sure that all parts that are not acid resistant such as nylon inlet filters column and flow cell are not connected during this step The acid is flushed through the p...

Страница 19: ...flow cell as described in the flow cell manual Never switch ON the flow cell when the cell cable is not correctly connected the cell is only partly or not at all filled with buffer the cell is wet outside particularly the part between the auxiliary and working electrode connection because substantial damage to the working electrode or electronics may occur 16 Before switching ON the flow cell make...

Страница 20: ...developed for continuous operation For maximum stability it is advised to leave the system ON continuously If preferred the flow cell may be switched OFF at night Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 21: ...18 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 22: ...s of appearance The nature of an item can be Control parameters with a cursor box can be attained via cursor buttons and changed by the and button Status without a cursor box a parameter reflects the current status Functions parameters in CAPITALS are commands accessible via function buttons Fig 3 DECADE keyboard The cursor is on Range which allows changes using the and button The ENTER button is ...

Страница 23: ...20 DECADE user manual edition 9 Overview of all DECADE screens Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 24: ...CHAPTER 3 The DECADE controller 21 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 25: ... voltage to 0 V or to the offset voltage see page 29 Azero AUTO PRGR control Controls the auto zero which can be programmed in a time file see page 37 CELL ON OFF DC SET PULS SET2 SCAN SET function Toggles between cell ON and OFF If the cell is switched ON in the pulse mode only E1 is applied the pulsation starts when PULS STAT screen is entered see page 51 In the DC or scan mode Eox Ered or Ecell...

Страница 26: ...s a time file has to be repeated If the DECADE is master this number can be 1 99 or continuous If the DECADE is slave the number of cycles is 1 see page 37 CycleTime AUTO SET control Controls the duration of a time file max 99 59 When this time is reached the execution of the time file stops If programmed the next run is started see page 37 Decade AUTO SET control Controls the status of the system...

Страница 27: ...ntrol Controls the oxidative or reductive cell potential Can only be set or changed after confirmation with the button Passing the 0 00 V value automatically changes the readout from ox to red and in reverse Eox or Ered DC STAT AUTO RUN DC only status Displays the oxidative or reductive cell potential File AUTO SET control Controls the number of the time file to be edited or activated In the DC mo...

Страница 28: ...njector If an electrically actuated injector is used optional it is possible to switch the injector with this function button MAIN RANGE screen function Returns to the MAIN screen MARK DC STAT PULS STAT function Triggers a marker signal on the recorder output NEXT RANGE screen function Enters the next xx SET screen Offs DC SET DC STAT AUTO PRGR PULS SET1 PULS STAT SCAN SET SCAN STAT control Contro...

Страница 29: ...ange select screen In the pulse and scan mode only the µA range can be used see page 29 RESET AUTO RUN function Aborts the time file and returns to the AUTO SET screen The cycle counter Cy is reset to 1 see page 37 Software version 3 00 and higher the outputs Aux 1 and 2 and Relays 1 and 2 are deactivated status 0000 RUN AUTO SET function Starts the execution of a time file master slave If the DEC...

Страница 30: ...1 In the DC and pulse mode master cycles 1 toggles between STOP and START to control the execution of a time file Pressing STOP aborts this run cycle counter Cy is not reset By pressing the same button START again the next cycle is started Cy Cy 1 see page 37 Software version 3 00 and higher STOP also deactivates the outputs Aux 1 and 2 and Relays 1 and 2 status 0000 This toggle is also active in ...

Страница 31: ...AT PULS STAT status Displays the actual left value and the pre set oven temperature right value set in xxSET Toven DC SET PULS SET1 control Controls the temperature of the oven Range off 15 60o C selectable in 1o C steps The oven is stable from 5 o C above ambient ts PULS SET2 control Controls the duration of the sampling time in the pulse mode The time can be set between 20 and 100 ms in 20 ms in...

Страница 32: ...e working electrode WE The recorder signal is manipulated by the CPU of the DECADE The details on data acquisition in the various ranges will be discussed for both output channels Internal organisation At the working electrode WE in the electrochemical flow cell the electron transfer takes place due to an oxidation or reduction reaction The resulting electrical current is amplified by the current ...

Страница 33: ...e I cell display screen resolution increases with more sensitive range The next step is the auto zero and offset compensation Then the signal is further manipulated for the recorder output or sent to the integrator output without manipulation Integrator output The integrator output has been designed to supply a clean purely analog signal from the I E converter Except for the auto zero and offset c...

Страница 34: ...t range in the DC SET or DC STAT screen After digital to analog conversion DAC the signal is sent to the REC output The recorder range selection has several consequences for the data acquisition Table III Table III Parameters affected by the recorder range setting parameter output comment signal output REC gain increases with more sensitive range offset REC INT see Table V marker REC 10 of full sc...

Страница 35: ...ses Therefore a compromise is made between maximum zero compensation and resolution To maintain a high auto zero resolution with accurate zero settings the maximum compensation is decreased with the integrator range Table IV Recorder ranges and maximum zero compensation Range pA nA µA 10 20 50 100 0 1 200 0 2 500 0 5 range 1000 1 0 overlap 2000 2 0 5000 5 0 10 0 0 01 20 0 0 02 50 0 0 05 0 10 0 20 ...

Страница 36: ...t is the large dynamic range and infinite resolution It is an analog output which means that the resolution is only limited by the integrator that is used In most integrators this is approximately 1 µV The 12 bits recorder output has a maximum output resolution of 500 µV Often the recorder output is chosen for data acquisition thus offering the possibility of smoothening by means of rise time filt...

Страница 37: ...r and the recorder output On the recorder output the offset is given as the percentage of the recorder range setting For example a 20 offset at 5 0 nA full scale setting will give a 1 0 nA offset This is a 200 mV offset when the maximum recorder output is 1 0 Volt For the integrator output the situation is more complicated because the offset percentage relates to the recorder range setting The int...

Страница 38: ...0 0 2 00 200 400 600 800 1000 5000 50 0 5 00 500 1000 1500 2000 2500 1 10 1000 Integrator output nA V Although this may seem a complex way of compensating the background current in practise it gives the best possible flexibility and optimum resolution of the 16 bits compensation in each operating range By simply changing the percentage offset or the recorder range almost any offset compensation ca...

Страница 39: ...36 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 40: ...to zero offset rise time electrically actuated injector if present and the DECADE output contacts to control the status of external equipment Range programming In certain analyses large differences in analyte concentration and peak height occur If the analyte with the highest concentration is on scale another analyte may be recorded at a low output resolution When the small peak is magnified with ...

Страница 41: ...B the output range is automatically switched during the run resulting in a considerable improvement of the output resolution of peak 1 Table VI time file used for output resolution programming time int range rec range rise time valve auto zero offset output E cell 00 00 nA 50 nA 1 s inject set 00 0000 0 80 V 00 10 nA 50 nA 1 s load not 00 0000 0 80 V 01 26 nA 0 5 nA 1 s load set 00 0000 0 80 V 01 ...

Страница 42: ...ion of each run will always be at least one minute longer In this minute the drift in the baseline is monitored Step by step example DECADE Master In this step by step guide the example from Table VI will be programmed In this example the system consists of an HPLC system a DECADE with an electric valve an integrator and an on line microdialysis set up The DECADE is master which means that the DEC...

Страница 43: ...r The duration of one run is set with CycleTime A step programmed at a time similar to or larger than the cycle time i e t 3 05 will not be executed Before the drift monitor can be set if required the first line in the time file has to be programmed The drift monitor is linked to the range setting of the first line in the time file at t 0 00 7 Press PRGR to go into the edit mode of the time file T...

Страница 44: ...m of 20 data lines 9 The last line in the time file is at t 1 55 By choosing SET you may return to the AUTO SET screen 10 In the AUTO SET screen CycleTime is set at 3 05 If required the drift monitor can be programmed In the nA range a choice can be made between off 1 pA min 0 1 nA min in 1 2 5 steps 11 Your system is now ready for automated operation A time file is started by choosing RUN in the ...

Страница 45: ... 14 When RESET is chosen the execution of the time file is interrupted and the AUTO SET screen appears The cycle counter is reset to 0 Cy 0 Software version 3 00 and higher RESET also deactivates the outputs Aux 1 and 2 and Relays 1 and 2 status 0000 Note In the master mode the HOLD STOP START and RESET functions are accessible only from the keyboard In the slave mode these inputs are accessible v...

Страница 46: ...nd higher 4 Prepare the LC EC system for analysis Programming the AUTO mode The programming of the time file is done in the same way as described for the master mode In the following steps the differences with the master mode are given 5 In the AUTO SET screen choose Decade Slave The number of cycles is controlled by the autosampler in the DECADE Cy is automatically set at 1 and can not be changed...

Страница 47: ...sampler Fig 13 The duration of this contact closure must be at least 100 ms Each time a run is started the AUTO RUN screen appears After the RESET command via relay1 the AUTO SET screen is displayed The auto zero command A ZERO is accessible during operation in the AUTO mode as long as I Cell is displayed Accessible keyboard commands in the slave mode are RUN STOP RESET and A ZERO This means that ...

Страница 48: ...ECADE Accessible keyboard commands in the slave mode are RUN STOP RESET and A ZERO Other events Inject load and inject marker A frequently used function is the inject load or inject marker as a trigger for starting the integration software This trigger is always accessible not only in the AUTO mode Fig 15 Output contact needed to start the integrator by switching the manual A or an automated elect...

Страница 49: ...nput command can be used for example to switch on and stabilise the flow cell early in the morning by means of a timer Programming output functions Four output functions can be programmed at each time The notation of the output 0000 corresponds to the four output controls at the back panel of the controller These are from left to right relay 2 relay 1 AUX2 AUX1 Fig 16 For example if AUX1 has to be...

Страница 50: ...DE uses TTL input contacts for START RESET AUTO ZERO TO POS A and TO POS B These contacts require a minimum TTL low pulse duration of 100 ms to be activated If multiple activations are required the next pulse must be given after 100 ms TTL high If the input is kept low only one activation will occur Fig 16 Programming an external contact closure using the Outp command in a time file Artisan Techno...

Страница 51: ...us of output connections is low 0 V The connections 1 8 are only accessible in the AUTO mode master and slave mode No Name Function 1 AUX1 open collector output I max 250 mA U max 28 V 2 AUX2 open collector output I max 250 mA U max 28 V 3 4 5 relay 1 contact between 5 common and 4 default or 3 I max 500 mA U max 28 V 6 7 8 relay 2 contact between 8 common and 7 default or 6 I max 500 mA U max 28 ...

Страница 52: ... injector to load 9 to pos B always level triggered In combination with electric valve forces injector to inject 10 inject load always status low In combination with manual injector with position sensor high load low inject 11 not conn 12 common always Ground Some contacts are level triggered they are activated by making an external contact closure for at least 100 ms with common low Releasing the...

Страница 53: ...50 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 54: ...z by the application of a series of potential changes This is particularly useful for certain applications where the working electrode is rapidly fouled due to adsorption of insoluble reaction products A well known application area of PAD is the analysis of carbohydrates Fig 17 1 Fig 17 Pulsed amperometric detection of 100 nmol l 2 pmol carbohydrates Peaks are sucrose 1 galactose 2 glucose 3 a lac...

Страница 55: ... Dialogue software The yellow crocodile clamp from the cell cable is connected to the injection valve to ensure proper grounding of the LC system However when an external injection valve is used auto injector in combination with a PEEK column CarboPac and with PEEK tubing a grounding problem may arise In that case a metal low dead volume connector should be placed near the flow cell which is conne...

Страница 56: ...pplied as a series of 3 potentials During time interval t1 the detection potential is applied The data collection occurs within t1 during time interval ts sampling time The time difference t1 ts is the stabilisation time Fig 18 Potential steps in pulsed amperometric detection A part of t1 is used for detection ts The metal oxide layer that is formed during t2 is removed during t3 resulting in a re...

Страница 57: ...an be used The measuring potential is compound dependent usually literature data can be used as a starting point for further optimisation A sampling time ts can be chosen between 20 and 100 ms in 20 ms steps These are multiples of the 50 Hz to prevent noise due to oscillations of the AC power supply Until a certain limit increasing ts will result in an increase of signal A limiting factor is the a...

Страница 58: ...ns that the integrator has an unnecessarily high sampling frequency This leads to large data files but certainly not to a better chromatogram Peak width and integrator frequency There are two important considerations with respect to integrator frequencies applied in HPLC If the frequency is too low data will be lost and artefacts may be introduced If the frequency is too high large data files are ...

Страница 59: ...ator frequency are both increased In the latter case the pulse duration is decreased which will change other detection parameters as well In practise the pulse frequency almost never interferes with the HPLC analysis Working electrode material Gold and platinum are used as working electrodes for PAD Glassy carbon appears to be unsuitable due to the high electric capacitance of this material Furthe...

Страница 60: ...f the noble metals For Pt and GC the negative peaks run far off scale however the profile is similar to the mirror image of the positive peaks Examples of carbohydrate analyses are given in Fig 17 Typical PAD pulse settings are given in Table X and Table XI these settings may be used as starting point for further optimisation Carbohydrates are oxidised at a pH of 12 or higher which puts specific d...

Страница 61: ...ences 1 D C Johnson D Dobberpuhl R Roberts and P Vandeberg Review Pulsed amperometric detection of carbohydrates amines and sulphur species in ion chromatography the current state of research J Chromatogr 640 1993 79 96 2 D C Johnson en W R LaCourse LC with pulsed ECD at gold and platinum electrodes Anal Chem 62 1990 589A 597A 3 W R LaCourse en D C Johnson Optimization of waveforms for pulsed ampe...

Страница 62: ...ribed Electrochemical reactions In electrochemical detection ECD a reaction of the analyte at an electrode surface is monitored This distinguishes ECD from most other detection techniques where detection is based on the physical properties of an analyte i e mass spectrometry molecular mass absorbance detection molar absorptivity For electrochemically active compounds the potential between referenc...

Страница 63: ...am On the metal working electrode an oxide layer is formed which affects the electrochemical reaction and makes the interpretation of a scanning voltammogram difficult Fig 23 Hydrodynamic voltammogram of nor epinephrine A at a glassy carbon working electrode and the current of the baseline B At E1 the electrochemical signal becomes diffusion limited An alternative for the chromatographic construct...

Страница 64: ... is increased the electrochemical reaction is enhanced hence the signal increases At a certain potential the I E curve flattens All analyte molecules that reach the working electrode are converted at such a high rate that the analyte supply becomes the limiting factor At the working electrode surface a stagnant double layer exists where molecular transport takes place by diffusion only Therefore t...

Страница 65: ...dation reduction reaction However this not only holds for the analyte but also for the background current and possible interferences An elevated temperature will therefore not automatically lead to a better detection A constant temperature is of paramount importance for a stable baseline and reproducible detection conditions Fig 25 Selectivity in LC EC of compound X and Y is optimised by choosing ...

Страница 66: ...his means that the flow rate not only affects temporal peak width and analysis time but also peak height Also the background signal is sensitive towards fluctuations in the flow rate Therefore it is important to use a pulse free solvent delivery system Fig 27 Construction of a hydrodynamic voltammogram for nor epinephrine Chromatograms are obtained at cell potentials ranging from 1 0 V back to 0 4...

Страница 67: ...ial is decreased by 50 or 100 mV and step 2 to 4 is repeated until the lowest potential setting Fig 27 5 The peak heights and the background currents are plotted against the working potential Fig 23 6 The working potential which gives the best sensitivity is obtained by plotting the signal to noise ratio against the working potential Construction of a scanning voltammogram The scan mode is program...

Страница 68: ...olution it should be diluted in HPLC buffer until the desired concentration 3 An injection loop of 100 µl is installed and the LC flow rate is set at 40 µl min The analyte plug will than be detected during approximately 2 5 minutes The flow rate is lowered if more scanning time is needed 4 An initial run is started in the DC mode at a high potential to estimate the required start and stop time of ...

Страница 69: ...AN SET screen an upper and a lower potential is chosen The cycle is set at half The range is set at 5 µA A scan speed of 10 mV s is selected The integrator or recorder must be connected to the REC output of the DECADE 7 The analyte is injected and the scan is started by pressing the START in the SCAN STAT screen of the DECADE at the time the analyte plug enters the flow cell see 4 8 A background s...

Страница 70: ...on Injector sensor starts system clock if Load Æ Inject Oven length 40 cm from 5 C above ambient to 60 C accuracy 0 5 C stability 0 1 C accommodates injector column pulse damper and flow cell Environmental Humidity Max 80 relative humidity non condensing 5 C 30 C linear decreasing to 50 rel humidity at 40 C DC mode Current ranges recorder 10 pA 5 µA in 1 2 5 steps Filter time constants 0 1 5 s in ...

Страница 71: ...r 80 ms Rear panel I O connections Mains Recorder 12 bits and Integrator analog 2 open collector AUX 1 and 2 I max 250 mA U max 28V and 2 relay outputs I max 500 mA U max 28 V cell on cell off 24 V output I max 500 mA Common Hold Busy Start Auto zero Overload Inject marker Electrically actuated injector control position of manual injector RS232C connector option Physical specifications Dimensions ...

Страница 72: ...tten in RAM Please contact supplier RECOVLD Recorder output is either above 1 0 V or under 1 0 V Pressing A ZERO may give an adequate read out again If the message ERROR 1 is displayed immediately after pressing A ZERO the auto zero function is unable to compensate for the offset and is out of the recorder range Advise use less sensitive range in Range select screen see also Saturation of output p...

Страница 73: ...70 DECADE user manual edition 9 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 74: ...nput is kept low only one activation will result See page 48 for detailed information on the I O contacts RS232C The RS232 option consists of a computer program DECADE Dialogue for Windows and another DECADE EPROM with R extension DECADE Dialogue for Windows is a multi functional control bar which handles all important settings of the DECADE via the RS232C port The program runs simultaneously with...

Страница 75: ... auto zero offset rise time electrical injector and control of DECADE output contacts for control of external equipment For users of integration software running under DOS DECADE Dialogue may still offer an attractive option A time file can be transmitted from a PC to the DECADE and executed from in the auto mode of the DECADE independently from the computer The possibility to construct a time fil...

Страница 76: ... REF not saturated Refill with wetted KCl crystals Retained peaks from previous runs Wait for elution of these very broad peaks Column is bleeding Replace column High amount of Fe in buffer Add EDTA to buffer rinse metal parts with 15 HNO3 Noisy baseline Possible cause Remedy Salt bridge in REF not saturated Refill with saturated KCl add wetted KCl crystals Air bubble in REF or in cell Remove air ...

Страница 77: ... REF see flow cell manual Temperature oscillations Set oven temperature Contaminated buffer high Icell Replace buffer do not recycle the buffer Fouled WE Clean WE see flow cell manual Fe in buffer Add EDTA passivate metal parts with HNO3 Saturation of output Possible cause Remedy Damaged REF Check with spare REF replace if necessary Damaged WE Replace cell block Cell incorrectly connected Check co...

Страница 78: ...pplied standard connection set ferrules and nuts The flow geometry through the pulse damper is symmetrical i e each one of the two connections can be used as inlet or outlet 3 Flush the damper with 20 ml HPLC grade water before use The shipping screw on the SSI pulse damper part no 12 0125 must be firmly tightened turn clockwise before operating or damage to the unit will result The SSI pulse damp...

Страница 79: ...tor and in fact resembles the capacitance of a well functioning VT 03 flow cell in an ideal HPLC set up The noise generated via the dummy should be less than 2 pA if the filter of the controller is set to 0 1 second provided that the dummy is within the fully closed Faraday shield at the same position as the flow cell see Table XIII for settings With a 1 second risetime the noise should be better ...

Страница 80: ...CHAPTER 14 Index 77 C H A P T E R 1 4 Index Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 81: ...tput 44 buttons DECADE keyboard 17 capacitance WE 55 carbohydrates chromatogram 49 pulse settings 55 Cell on off I O contact 44 46 CELL ON OFF function 20 cleaning pulse 37 common I O contact 46 47 contact closure 42 Cy status 20 Cycle control 21 Cycle status 21 Cycles control 21 CycleTime control 21 data acquisition 27 DC mode specifications 65 DECADE Dialogue 35 69 Decade control 21 degassing mo...

Страница 82: ... dipswitch settings 67 inject marker trigger 43 electrochemical reaction 57 Eox control 22 Eox status 22 Ered control 22 Ered status 22 error messages 67 Faraday shield 13 File control 22 Filt control 22 filter 22 29 flowcell installation 14 fuses 12 replacement of 3 ground 47 grounding 13 50 hold busy I O contact 44 Hold Busy I O contact 47 HOLD 0 1 function 22 I E converter 27 Artisan Technology...

Страница 83: ...rigger 43 injection valve dipswitch settings 67 installation 12 Tefzel Vespel rotor 12 installation DECADE 11 flowcell 14 pulse damper 73 INT 27 integrator connection of trigger 37 43 pulse mode frequency 54 integrator output introduction 27 maximum current 28 maximum zero compensation 28 vs REC output 31 keyboard DECADE 17 leakage 13 lift instructions 11 MAIN function 23 MARK function 23 marker 2...

Страница 84: ... 44 47 OVLD 67 passivation with nitric acid 13 potential optimisation 57 power supply 11 PREV function 24 PRGR function 24 pulse damper 12 73 pulse mode characteristics 50 literature references 56 optimisation 52 output frequency 52 potential settings 51 working electrode 54 PULSE mode specifications 65 pulsed amperometric detection 49 range integrator ranges 28 overlap 30 overview of 30 programmi...

Страница 85: ...ramming of 42 resolution integrator recorder output 29 31 zero compensation 30 rotor Tefzel 12 50 rotor Vespel 12 50 RS232 option 69 RUN function 24 S N ratio 62 71 safety practices 3 scan mode example 62 scanning voltammogram 58 SCAN mode specifications 65 Scan control 24 screens DECADE overview 18 SCROLL function 24 service 4 SET 1 2 function 25 slave 40 accessible commands 42 accessible functio...

Страница 86: ...rruption of 40 42 RS232 option 70 step by step example 38 40 trigger started 41 to pos A B I O contact 44 47 Toven control 26 status 26 trigger for start integrator 37 43 for start TimeFile 40 troubleshooting 71 ts 50 ts control 26 TTL 45 69 Vespel rotor 50 voltage selector mains 11 voltammogram construction 58 62 introduction 57 working electrode material 54 zero compensation 28 Artisan Technolog...

Страница 87: ...84 DECADE user manual edition 9 zero compensation resolution 30 Artisan Technology Group Quality Instrumentation Guaranteed 888 88 SOURCE www artisantg com ...

Страница 88: ...quipment Have surplus equipment taking up shelf space We ll give it a new home Learn more Visit us at artisantg com for more info on price quotes drivers technical specifications manuals and documentation Artisan Scientific Corporation dba Artisan Technology Group is not an affiliate representative or authorized distributor for any manufacturer listed herein We re here to make your life easier How...

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