The safe operation method of the micro counting method particle analyzer must strictly follow the pharmacopoeia specifications and instrument operation requirements. The specific process is as follows:
1、 Preparation before operation
1. Environmental control: Operations must be carried out in laminar flow purification stations or ultra clean rooms, and the number of environmental particles must comply with pharmacopoeia standards (≥ 10 μ m particles ≤ 20 particles per 50ml of water, ≥ 25 μ m particles ≤ 5 particles).
2. Instrument calibration: The microscope eyepiece micrometer needs to be calibrated regularly. The pore size of the filter membrane should be 0.45 μ m, and the particle count of the filter membrane itself should be checked (≥ 10 μ m particles ≤ 5 particles, no ≥ 25 μ m particles).
3. Sample processing: Samples such as freeze-dried powder that are prone to bubble formation should be gently shaken and mixed to avoid severe flipping that may cause protein denaturation.
2、 Key operational steps
1. Filtration and drying:
Use a clamp type quantitative filter to filter the sample, and the suction pressure should be controlled (protein preparations can be pressurized to 75 pallets).
The filter membrane needs to be completely dried to avoid residual moisture interfering with counting.
2. Microscopic observation:
Magnify by 100 times, use a calibrated eyepiece micrometer to measure particles ≥ 10 μ m and ≥ 25 μ m, and record their morphology (such as fibers and metal debris).
High concentration samples need to be diluted to prevent particle overlap from affecting statistics.
3、 Safety precautions
1. Anti pollution measures: Tools such as tweezers and filters should be thoroughly cleaned with water for particle inspection to avoid cross contamination.
2. Bubble control: Samples with high viscosity need to be allowed to stand and degas, or rotary mixing can be used instead of flipping.
3. Data review: When the results of the photoresist method are abnormal, the microscopic counting method shall be used as the final judgment basis.
4、 Maintenance and Verification
1. Regularly calibrate the microscope with a micrometer to ensure measurement accuracy.
2. The reliability of automatic filtration, drying and other processes needs to be verified for fully automatic models.