Continuous dispensing is one of the most common functions of electric pipettes, especially for the same volume of liquid dispensing based on microplates. The technology behind the multiple dispensing function 1. Stepper continuous liquid separation function The continuous dispensing function is designed for multiple dispensing optimization. Depending on the number of dispenses and the dispense volume each time, this function automatically calculates the volume required to complete the dispense sequence. In order to meet the volume required for reverse pipetting, the pipette will additionally inhale a set volume of 10% as compensation.  Due to the reverse pipetting technique itself and capillary action, the first step of the liquid separation in the continuous liquid separation is significantly less accurate than the subsequent steps, so the first step of the liquid separation needs to be discarded, which can increase the accuracy of the subsequent steps. For these reasons, it is recommended to discard the first step of the liquid when using a continuous dispenser . In the Stepper continuous dispensing mode, the “pre-step†is automatically added as the first step, and the “pre-step†dispensing recommendation is directly discarded or returned to the original solution. In order to reduce liquid waste, the volume of the pre-step is optimized to about 3% of the set volume. For example, a 10-300 μl pipette with a pre-step volume of approximately 9 μl. 2. Matrix programming function The Matrix programming module is used for complex pipetting of a variety of different applications. The basic idea is that the user makes program associations and module calls for each type of pipetting operation (such as inhalation, draining, mixing, etc.) for programming. It should be noted that the Matrix module defaults to taking into account any pipetting techniques and influencing factors that may affect the pipetting results when the user is programming. This is different from the preset preset function. The pipetting function in the preset module has set the optimal function to the default value to ensure the accuracy of pipetting. Note. This is equivalent to the compensation volume for reverse pipetting, which is done automatically in the preset program stepper. Note that the above recommendations depend on the pipetting mode, and different pipetting modes may require a smaller or larger compensation volume to meet the demand. note. The following example is used to illustrate how to program a 10 x 20 μl continuous dispensing operation in Matrix mode with a 10-300 μl E1-ClipTip pipettor. Continuous dispensing of Stepper and Matrix mode comparison Since the continuous dispensing stepper mode has been optimized for multi-step dispensing, ie the reverse pipetting technique is used during pipetting, the piston movement allows for an additional volume to be drawn. When the total volume of the solution required for continuous dispensing is close to the maximum range of the pipette, it is recommended to use the continuous dispensing Stepper mode, which has defaulted to inhaling an extra volume. For example, when using a 10-300 μl pipette for 10 x 30 μl dispensing, the stepper mode is recommended. You Cha With Mixnuts,Roasted Nuts,Nut Snacks,Delicious Nuts Zhejiang Shanying Trading Co.,Ltd. , https://www.shanyingtrading.com
The multiple dispensing function in the electric pipette and continuous dispenser uses reverse pipetting. In reverse pipetting, the volume of the inhaled liquid is greater than the set value. This extra volume is compensated so that the volume of the dispensing at each step of the continuous dispensing is uniform. Therefore, we cannot think that 100 μl of the solution is discharged 10 times, and 10 μl of the liquid separation volume is accurate in the 10 μl/time dispensing process. It is very likely that the liquid will be exhausted before the last step. In the reverse pipetting controlled electric pipette and continuous dispenser, after the final one-step dispensing operation, the remaining solution will be discarded by the "clean" and "blow dry" operations.
E1-ClipTip continuous dispensing function 
For example, when using a 10-300 μl pipette with a filling volume of 300 μl, the pipette inhalation volume is approximately 330 μl, but the display shows 300 μl. 
The volume of the pre-step is automatically recorded in the inhalation volume. If the customer wants to minimize the amount of liquid, the pre-step can be turned off.
The Matrix module includes two continuous dispensing steps: automatic and multi-step. When using multi-step or automatic steps, it is recommended to use the following settings to ensure the best function
a. Aspiration procedure: When the continuous dispensing function is involved in the procedure, an additional 10% of the set volume is required after the set volume has been aspirated, which is necessary to complete the continuous dispensing.
i. For example, for a 10-300 μl pipette, an additional 30 μl of compensation volume is required to complete the entire series of dispensing.
Ii. When dealing with liquids whose density is higher than that of the liquid, it is recommended to draw more than 10% of the set volume as the compensation solution.
b. In order to improve the accuracy of pipetting, it is recommended to add an additional liquid separation step before continuous liquid separation to discharge approximately 3-5% of the solution.
- The additional dispensing step is similar to the "Pre-Step" function in the Continuous Dispensing Stepper mode.
- When the additional dispensing volume is close to the minimum volume of the pipette, the minimum volume of the pipette can be used as the volume of the additional dispensing step as a "pre-step" prior to formal dispensing. 
The Matrix mode is designed to support a variety of different pipetting modes, so the normal forward pipetting technique during inhalation is not allowed to inhale an extra volume.
Optimize the accuracy of the multi-step dispensing function
Note: The single-point calibration curve only applies to a specific volume of calibration and therefore can only be used with a corresponding volume.
Instructions on how to create a single-point calibration curve, store the program, and how to call the calibration of the curve can be found in the E1-ClipTip manual.
Guidelines for multi-step dispensing
However, the continuous/multi-step dispensing function in the electric pipette/continuous dispenser uses a reverse pipetting technique. Unlike the forward pipetting technique, there is no official ISO standard as a guide for the continuous dispensing function in air-displaced pipettes. Therefore, Thermo Scientific, like other manufacturers, has not published specifications applicable to these functions (accuracy). With the standard of precision).
to sum up:
ï¬ Â· The continuous liquid separation function uses reverse pipetting technology.
• Continuous dispensing requires an extra volume above the theoretical volume required to complete the dispensing series.
• In order to optimize performance, it is recommended to add an extra volume or a pre-step in the pipetting sequence before the multi-step dispensing series.
ï¬ â€¢ For applications that use only continuous pipetting, it is recommended to use the continuous dispensing module Stepper in the preset program.
• When the total volume required for continuous dispensing is close to the maximum range of the pipette, it is recommended to use the continuous dispensing mode stepper.
• To optimize the accuracy of a step volume, it is recommended to create a 1-point calibration procedure for this volume.
ï¬ Â· There are currently no publicly available guidelines for continuous pipetting.