Flowcell is a type of flowthrough cell. As the name suggests the sample flows through the cell. During this process. the optical density of the sample is measured. After that, the sample comes out of the cell. Then the sample goes to waste. Thus, it is a component within a machine, where the absorbance of the sample is measured. Flowcell is used in various medical equipment such as a spectrophotometer, biochemistry analyzer, HPLC, etc. Here we will discuss the design and the price of the flowthrough cell in the case of the semi-auto biochemistry analyzer.
Besides that, we will also discuss the impact of contamination of the cell and the method of handling those problems.
Flowcell in HPLC
Design of Flowcell for Semi-Auto Biochemistry Analyzer
It is generally made up of UV quartz. The common volume of the cell is 30 μl. It has got an internal diameter of 2 mm. Similarly, the path length is 1 cm. If you look closely, you will see two windows exactly opposite to one another. From these two windows, light enters and then transmits out of the cell.
The size of the flowcell may differ from one to another. The other sizes include 50μl, 70μl, 100μl, etc. For this, flowcells will have a wider internal diameter. Also, the path length can be 2 cm or 3 cm. But, it should never be less than 1 cm.
If the flowcell is not cleaned from time to time, there can be the following problems
The main problem will be the contamination of the flowcell. The contamination can again be the reason for numerous problems. For example, contamination can cause the obstruction of the pathway of the light passing through the sample. Thus, this will affect the absorbance of the light, giving an error in the result.
The other problem is that the contamination can occupy a major portion of the flowcell. Hence, this will lead to insufficient filling of the cell. Besides that, there will also be chances of bubble formation.
When do you need to clean the flowthrough cell?
1. Before switching from one test to another
If you do not clean the flowcell while switching from one test to another, there can be chances of cross-contamination. For that, take at least 1.5 ml of distilled water and rinse the biochemistry analyzer for at least 5 seconds.
2. While shutting down the biochemistry analyzer
Rinse the flowcell, at the end of the day. For that, rinse the cell for about 2 mins with the distilled water.
3. During the operation of the machine
Press the rinse/wash button on the keyboard of the machine. This will cause the peristaltic pump to operate in continuous mode. After not less than 10 seconds, press the rinse/wash button again. This will cause the pump to stop.
Now, prepare 5 ml of ethanol. Sip it for 5 seconds and then press stop. Wait for 1o seconds. Then again click Wash. Finally, rinse it with the distilled water for 10 seconds.
Repeat the above process 2-3 times. You need to do this process twice a day. You can use other cleaning solutions as well. Some of them are 0.1 N KOH (NaOH) solution, enzyme solution capable of decomposing the protein deposits, etc. Commercially, you can also find a flowcell cleaner.
Alternatively, you can make a new program for cleaning your flowcell.
|Wavelength||–||You can choose any wavelength that you like.|
|Temperature||370C||Choosing 370C will make the rinsing process faster|
|Unit||–||You can choose any unit that you like|
|Blank||Reagent||Feed distilled water for reagent blank|
|Delay time||10 seconds||This will be the time for cleaning the flowcell.|
|Sipping Volume||1000 μl||Do not alter this value|
|Upper Limit||–||You can set any value that you like|
|Lower Limit||–||You can set any value that you like|
|Sample/ calibrator volume||–||You can set any value that you like|
|–||You can set any value that you like|
|No. of standards||–||It does not matter|
|No. of calibrations||–||It does not matter|
|Standard/calibrator||–||it does not matter|
In the end, rinse the flowcell with distilled water for 10 seconds.
4. Hard Cleaning
Sometimes, due to the negligence of the user, there might be a blockage in the flowcell. This might be due to the feeding of whole blood or improper cleaning. So, if the above method fails to clean it, then take 3-5 ml of distilled water in a syringe. Then, remove the tubing connected to the peristaltic pump. After that, force the distilled water into the flowcell with the help of the syringe. But, do not apply excessive force. Else, it may damage.
The price of the flowcell depends upon a number of factors such as the size, the material used in the cell, company, etc. So there is no exact price of flowcell in the Nepalese market. However, based on my experience, I can say that the price for the quartz flowcell can range from around Rs 30,000 to Rs 50,000. However, to know the exact price you need to contact the relevant supplier.
Before you purchase it, you need to be extra careful. The flowcell of one company may not fit with that of another company. If you are buying the flowcell from the same company, you may not need to worry about the product. However, if you want to purchase from another company, then I suggest you carry the sample piece. This will be useful while making a size comparison with a new one.