Preguntas frecuentes
Naturaleza refinada, calidad definida
Ciencia verde para una vida mejor
How to Measure Turbidity and Transparency of Bacteriological-Grade Agar Solutions?
To assess the clarity and homogeneity of dissolved bacteriological-grade agar, ensuring compliance with optical transparency and impurity control requirements for microbiological applications.
Prepare a 1.5% agar solution (using deionized water)
Heat until completely dissolved (≥95°C, with stirring for 10 minutes)
Cool to 50–55°C (maintain liquid state to prevent gelling)
|
Method |
Procedure |
Acceptance Criteria |
|---|---|---|
|
A. Turbidimeter Method |
Pour sample at 50°C into a cuvette and read NTU value |
≤10 NTU (regular grade) |
|
B. Spectrophotometer Method |
Measure absorbance at 650 nm using a pre-warmed cuvette (deionized water as blank) |
OD₆₅₀ ≤ 0.05 |
|
C. Light-Transmission Visual Inspection |
In a darkroom, pour sample at 50°C into a transparent glass bottle/test tube. Shine a bright flashlight or parallel beam from the side and observe: |
The solution should be uniformly transparent, with no visible suspended particles, flocs, or obvious opalescence; the light beam should pass through without significant scattering. |
|
D. Text-Legibility Method |
Pour sample into a transparent tube and place it over standard printed text (e.g., 10 pt font). Observe text clarity. |
Font outlines should be clearly recognizable without noticeable blurring. |
Complete all tests within 10 minutes after dissolution
Strictly control measurement temperature at 50–55°C
Use dust-free glassware and filtered deionized water
For darkroom bright-light inspection, let the sample stand for 1 minute before observation to avoid interference from bubbles
Combine observations against black and white backgrounds to improve detection of impurities and inhomogeneity
|
Item |
Record |
|---|---|
|
Sample Information |
Batch no., concentration, test temperature |
|
Turbidity/OD Value |
NTU value or OD₆₅₀ value |
|
Light-Transmission Results |
Describe uniformity, presence of particles/turbidity |
|
Text-Legibility Results |
Clear / Slightly blurry / Unreadable |
|
Overall Judgment |
Pass / Fail (based on internal standards) |
Recommended Internal Standards：
Regular bacteriological-grade agar: NTU ≤ 10, no obvious particles in light-transmission check, text legible
High-purity agar: NTU ≤ 5, uniform transparency in light-transmission check, text clearly legible
Email: info@cagcolloids.com
Tel: 0086-19884908291 / 0086-573- 88067623
Website: www.cagcolloids.com
Address: No. 399, East Tongfu Road, Tongxiang City, Zhejiang Province. China.
