#quality_control
#Sampler
Sampler quality control:
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Before starting the quality control, before any action, the sampler should be serviced using the relevant service tools such as oil, white alcohol, and a rod to open possible blockages. If the physical structure of the sampler is correct, quality control is done.
Checking the accuracy of the samplers is done twice a year in the following two ways:
1⃣ Colorimetry (using edible green color and paranitrophenol)
2. Weighing method
Quality control of colorimetric brush sampler
1. Edible green color
In common work, samplers are divided into two groups: 10-100 microliters and 100-1000 microliters. A stock solution of edible green color should be prepared for each group.
For group 100-10 microliters of 155 mg percent solution of green dye in distilled water and group 1000-100 microliters of 15.5 mg percent solution is prepared.
The concentration in the stock solutions is chosen in such a way that the 155 mg% solution after dilution to 101.1 and the 15.5 mg% solution after dilution to 11.1 have an absorbance of about 0.4.
2. Paranitrophenol solution: Paranitrophenol solution can be used instead of edible green color. In this method, the stock solution is prepared according to the volume of the sampler.
Paranitrophenol (C6H5NO3), indicator pH (5.4-7.5) MERCK Art.6798
Preparation of stock solution for samplers with a volume of less than ten microliters: Dissolve 420 mg of paranitrophenol in 100 ml of distilled water.
Accuracy control: in ten test tubes, depending on the type of sampler, a 101/1 dilution is prepared from the stock solution in 0.01 normal sodium. The contents of the tube are completely mixed and then the light absorption of the solution inside each tube is read at a wavelength of 405 nm against a normal gain of 0.01.
Accuracy control: add 1 ml of stock solution to 1000 ml of 0.01 normal soda in a 1-liter volumetric flask and mix thoroughly.
Preparation of stock solution for samplers with a volume of 10-100 microliters: Dissolve 42 mg of paranitrophenol in 100 ml of distilled water.
Accuracy control: in ten test tubes, depending on the type of sampler, prepare a dilution of 1/101 from the stock solution in 0.01 normal soda, mix the contents of the tube completely, and then measure the light absorption of the solution inside each tube at a wavelength of 405 nm against soda.
0.01 read normally.
Accuracy control: add 1 ml of stock solution to 100 ml of normal sodium 0.01 in a 100 ml volumetric flask and mix thoroughly.
Preparation of stock solution for samplers with a volume of 100-1000 microliters: Dissolve 42 mg of paranitrophenol in 1 liter of distilled water.
Accuracy control: in ten test tubes, depending on the type of sampler, prepare a 1/11 dilution of the stock solution at a normal 0.01 percent gain. Mix the contents of the tube completely and then read the light absorption of the solution in each tube at a wavelength of 405 nm against a normal gain of 0.01.
Accuracy control: add ten milliliters of the stock solution to 100 milliliters of 0.01 normal soda in a 100 ml volumetric flask and mix thoroughly. The light absorption of these solutions after applying the dilution factor at the wavelength of 405 nm will be about 0.55.
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