Cyclic Voltammetry: Hints and Tips - Revision history

Oliver: /* Noise */

2018-05-31T02:28:08Z

‎Noise

Oliver: /* Hum/Sinusoidal/Oscillating noise */

2017-06-06T03:46:57Z

‎Hum/Sinusoidal/Oscillating noise

Oliver: /* Hum/Sinusoidal/Oscillating noise */

2017-06-06T03:44:58Z

‎Hum/Sinusoidal/Oscillating noise

Oliver: /* Hum/Sinusoidal/Oscillating noise */

2017-06-06T03:44:15Z

‎Hum/Sinusoidal/Oscillating noise

Oliver: /* Hum/Sinusoidal/Oscillating noise */

2017-06-06T03:43:46Z

‎Hum/Sinusoidal/Oscillating noise

Oliver: /* Hum/Sinusoidal noise */

2017-05-30T02:03:49Z

‎Hum/Sinusoidal noise

Oliver: /* Troubleshooting */

2017-05-30T02:02:36Z

‎Troubleshooting

Oliver: /* Troubleshooting */

2017-05-30T02:01:41Z

‎Troubleshooting

Oliver: /* Hum/Sinusoidal noise */

2017-05-30T02:00:34Z

‎Hum/Sinusoidal noise

Oliver: /* Reference Electrode */

2017-04-28T04:01:34Z

‎Reference Electrode

← Older revision		Revision as of 02:28, 31 May 2018
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	To check for noise emanating from nearby equipment, connect a high value resistor (1 megohm or more) to the potentiostat lead wires, working electrode lead to one end of the resistor, and reference and auxiliary leads to the other end. This is shown in [[Check_the_Performance_of_the_Potentiostat_with_Potentiostat_Maintenance_Check\|this video]]. Examine the current signal (any potential even zero volts can be used) on a ranges of 10 microampere or less, so that you can see the signal noise. Make sure all low pass filters are turned off. As you move the resistor about, for example near power leads and computers, you may find noisy 'hot spots'.		To check for noise emanating from nearby equipment, connect a high value resistor (1 megohm or more) to the potentiostat lead wires, working electrode lead to one end of the resistor, and reference and auxiliary leads to the other end. This is shown in [[Check_the_Performance_of_the_Potentiostat_with_Potentiostat_Maintenance_Check\|this video]]. Examine the current signal (any potential even zero volts can be used) on a ranges of 10 microampere or less, so that you can see the signal noise. Make sure all low pass filters are turned off. As you move the resistor about, for example near power leads and computers, you may find noisy 'hot spots'.
		+
		+	Also see the application note covering [https://www.edaq.com/wiki/Problems_with_Noise Problems with Noise] in general data recording.

	==== Hum/Sinusoidal/Oscillating noise====		==== Hum/Sinusoidal/Oscillating noise====

@@ Line 283: / Line 283: @@
 ==== Hum/Sinusoidal/Oscillating noise====
 [[File:Oscillations, sinusoidal signal in EChem software.jpg|300px|thumb|right|Oscillations in EChem software]]
-Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here
+Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here]
-].
 ==== Drift ====

@@ Line 283: / Line 283: @@
 ==== Hum/Sinusoidal/Oscillating noise====
 [[File:Oscillations, sinusoidal signal in EChem software.jpg|300px|thumb|right|Oscillations in EChem software]]
-Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [[https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here
+Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here
-]].
+].
 ==== Drift ====

@@ Line 283: / Line 283: @@
 ==== Hum/Sinusoidal/Oscillating noise====
 [[File:Oscillations, sinusoidal signal in EChem software.jpg|300px|thumb|right|Oscillations in EChem software]]
-Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here
+Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [[https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here
-].
+]].
 ==== Drift ====

@@ Line 283: / Line 283: @@
 ==== Hum/Sinusoidal/Oscillating noise====
 [[File:Oscillations, sinusoidal signal in EChem software.jpg|300px|thumb|right|Oscillations in EChem software]]
-Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate.
+Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate. More suggestions [https://www.edaq.com/wiki/Frequency_Asked_Questions_Potentiostats#Sinusoidal.2FOscillating_noise here
 ==== Drift ====

@@ Line 281: / Line 281: @@
 To check for noise emanating from nearby equipment, connect a high value resistor (1 megohm or more) to the potentiostat lead wires,  working electrode lead to one end of the resistor, and reference and auxiliary leads to the other end. This is shown in [[Check_the_Performance_of_the_Potentiostat_with_Potentiostat_Maintenance_Check|this video]]. Examine the current signal  (any potential even zero volts can be used) on a ranges of 10 microampere or less, so that you can see the signal noise. Make sure all low pass filters are turned off. As you move the resistor about, for example near power leads and computers, you may find noisy 'hot spots'.
 ==== Hum/Sinusoidal noise====
 Sometimes a sinusoidal interference is seen on the current signal. This is almost always due to an aliasing of mains interference (at 50 or 60 Hz) against the sampling frequency and sampling period. If the scan rate is less than 100 mV/s then use a 10 Hz low pass filter setting on the current signal. This will remove almost all the mains interference without distorting the peak shapes in the voltammogram. A similar effect can be achieved by making the sampling period an integral number of mains cycles (i.e. a multiple of 20 ms at 50 Hz, and 16<sup>2</sup>/<sub>3</sub> ms at 60 Hz, while a multiple of 100 ms works for both 50 and 60 Hz), however this also requires a relatively slow scan rate.

@@ Line 225: / Line 225: @@
 Three-electrode potentiostats are designed so that no current passes through the [http://wikipedia.org/wiki/Reference_electrode reference electrode], thus it is not subject to any electrolysis reaction and maintains its integrity (and provides a constant potential) throughout the experiment. Unfortunately most reference electrodes are based on aqueous chemistry and are somewhat incompatible with the anhydrous immiscible organic solvents that are often used for cyclic voltammetry.
 With some organic solvents (eg acetonitrile) a silver wire/silver ion reference electrode can be constructed from a standard refillable electrode:
-*[http://www.edaq.com/ET073 Ag/AgCl miniature refillable electrode]
+*[http://www.edaq.com/ET073-1 Ag/AgCl miniature refillable electrode]
 At other times a simple platinum (or platinum coated wire) can be used as a pseudo-reference electrode and  after the experiment [http://wikipedia.org/wiki/Ferrocene ferrocene] (which has a known E<sub>1/2</sub>) is added to the reaction mixture to calibrate the system.
 A modern innovation is the leakless reference electrode which uses a solid polymer junction to separate the inner aqueous filling solution of the electrode from the other reaction mixture, see
-*[http://www.edaq.com/ET069 ET069 5 mm diameter Leakless Ag/AgCl electrode]
+*[http://www.edaq.com/ET069-1 ET069 5 mm diameter Leakless Ag/AgCl electrode]
-*[http://www.edaq.com/ET072 ET072 2 mm diameter Leakless Ag/AgCl electrode]
+*[http://www.edaq.com/ET072-1 ET072 2 mm diameter Leakless Ag/AgCl electrode]