Faqs

It is very easy. With the aid of a micropipette just place a drop of 60 µL making sure you cover the three electrode system (working, auxiliary and reference electrode). You can also immerse the electrode into solution. Just make sure that the 3 electrode system is in contact with your solution.

Take a look at the “Publications” section in our website and, with the help of filters and the search engines, you may find publications from other Researchers that are using our products in a similar application than yours. This information may be a useful as a guidance on material or design of SPE could be suitable. Of course,  you can contact us anytime and we may provide you with related advice. Still, you have the complete knowledge in your specific research and testing the SPEs would be the best way to find out which reference suits you better.

Electrodes are ready to be used and no general pretreatment protocol is established. With screen-printed electrodes you avoid tedious polishing steps of conventional solid electrodes before performing a measurement. Still, some researchers apply electrochemical pretreatments for specific applications. For example, the typical treatment of gold electrodes is preforming successive cycles in sulphuric acid (0.1M) between 0 and 1.6V at s.r. 100mV/s. You can check the “Publications” section in our website to find out what other users of these references usually do.

SPEs are designed as single use platforms for the development of different (bio) sensors. We recommend and guarantee their  best performance when used as disposable. The possibility of re-using the electrodes and if so, how many times, really depends on your specific analysis protocol and should be then decided by each researcher as part of their optimization process.

SPEs can be used in acid, neutral and basic media as any other conventional solid electrode.

Most of catalogue electrodes are manufactured over ceramic (alumina). We also work with white and transparent plastic (PET), with PCB (FR4) and glass (pyrex). Manufacturing in other materials can be evaluated under request as a customized product.

Yes, we have the capability of customizing electrodes under your requirements. You just need to provide us with all details regarding dimensions and materials and send us a rough sketch of your desing for evaluation. Based on your request we will then provide you with a scalable price.  You can write us to info.dropsens@metrohm.com and we will provide you with a questionnaire to easily fill all the details that are needed.

The difference between AT and BT electrodes is that they are made with different kinds of gold screen-printing inks. AT ink is cured with a high temperature process (around 900ºC) whereas BT uses a low temperature process (around 150ºC).   We have these two kinds of gold in order to offer a wider electrochemical behaviour to researchers when it comes to gold electrodes. In other words, AT and BT models can show different or similar behaviour depending on the particular experiment i.e. they may have different or similar electrochemical properties depending on the redox system used. There are not defined criteria to describe the properties of each model because these properties depend on the sensor developed, on the electrodes and on the redox molecule tested. For example, ferricyanide shows better electron transfer on AT electrodes than on BT electrodes; also, in a general way we can say that AT models sometimes show better repeatability results, but customers often select BT models to develop biosensors on them. For these reasons, the best way to start working with these electrodes could be testing them and compare their characteristics for the specific application. In order to find out which reference is more suitable to your concrete application, you can check the “Publication” section in our website or you can also acquire a box of ref. DRP-AUMIX, including a mix of gold electrodes of high and low temperature.

Yes, we have tested that autoclave during 5 min and 120ºC does not affect SPE performance.

It mostly depends on the substrate and the presence of dielectric (green polymer):

• Ceramic SPEs with dielectric can resist up to around 100 ºC  whereas ceramic SPEs without dielectric (such as ref. IDEAU200) can resist up to 800 ºC.
• Plastic substrate electrodes can resist up to 80 ºC
• Glass substrate electrodes can resist up to 450-500 ºC

SPEs are meant to be used with aqueous solutions however they resist certain organic solvents under concrete conditions. If you plan to use our SPEs with organic solvents contact us and we will inform you on the tests we have carried out.

Metrohm DropSens’ standard screen-printed electrodes use a silver pseudoreference electrode. There is a shift of -131 mV when compared to classical Ag/AgCl reference electrode in KCl 0.1 M solution. If you are interested in working with an Ag/AgCl pseudoreference electrode you have available in our catalogue refs DRP-11L and DRP-C11L. Any of our catalogue models or any design can be manufactured as customized with Ag/AgCl ink.

Yes, there isn’t any inconvenience in using an external reference electrode instead of the printed one. There is also the option to custom your electrodes without screen- printing reference electrode.

It depends on the analysis you are performing, but given the functioning of a FIA system most of the times there is no need to change the electrode and you can reuse them. Each process should be optimized for your concrete application.

The metal is deposited over the ceramic substrate by PVD and a thin layer of 1μm pure metal is obtained. Besides this, the roughness of these electrodes corresponds to the roughness of the alumina substrate, it means Ra = 1 μm.

Interdigitated electrodes over glass substrates are manufactured by photolithography. The layers obtained are within the range from 150 to 200 nm.

In order to get a better adhesion of gold or platinum over glass substrate, a thin layer of titanium is deposited before sputtering with gold or platinum.

There are many possibilities including gold and silver electrodes (ref. DRP-220AT, 220BT, 250AT, 250BT, C013, 013). Another possibility could be to use carbon modified electrodes with gold or silver nanoparticles  (ref. DRP110GNP, 110AGNP). You may find a list of related articles on this application on the “Publications” section of this webpage.

Streptavidin or ExtrAvidin modified electrodes are the most convenient ones for immobilization of large amount of biotinlylated molecules.

Streptavidin is a protein purified from Streptomyces avidinii and it is characterized by an extraordinarily high affinity for biotin. Streptavidin is used in biotechnology due to the strongest non-covalent interaction to biotin.

These electrodes are stable at room temperature. However, we recommend storing it at 2-8^oC in a fridge where the temperature is well controlled.

You could work with most of available Metrohm DropSens electrodes, depending on your specific needs. Our publication page includes numerous reference papers that will help on your research.

High-throughoutput tests can be performed in batch or in flow using a wide range of products available at Metrohm DropSens. You can select from a wide range of screen-printed 96X electrochemical ELISA plates or 8X electrode arrays, which can be a good option to perform multiplex assays. Individual electrodes used with specific multichannel connectors and instruments are also suitable for multiplex analysis.     On the other side, BIACELL or FIASYSTEM are also suitable solutions for performing high-throughput tests.

The bottom of the well-plate is a PCB substrate while the wells are defined by standard black polymer used in ELISA plates for fluorescence. Depending on your system, they can be compatible just that PCB substrate do not interfere with your signal.

For transmission analysis while performing an electrochemical test we recommend transparent working electrodes references PEDOT10, COTE10, ITO10 or AUTR10. The different available materials, PEDOT, Carbon, Indium Tin Oxide and transparent Gold are perfect for getting a good transmission signal. You can check all the references acquiring the mix of OTE, OTEMIX.

These Screen-printed electrodes have integrated a one-channel flow-cell an easy control of the sample volume in batch mode and also in flow injection analysis.

The cover is highly stable and high flow rates can be achieved. For example, 4 mL/min could be used in a measurement. However the optimal flow rate should be checked as it depends on your specific experiment.

Because they show a specific behaviour due to nonlinear diffusion and the observed steady-state currents- which allow the study of electrochemical reactions in short time – yield in higher currents.

It is the ratio of currents at the generator and collector electrodes, when using G-IDE222 and G-IDE555 as generator/collector sensor.

The screen-printed PEDOT layer has a thickness of 3 +/- 1 μm.

You can check here information for each reference.