Hello everyone. I have two question two asked.
1. I did the encapsulation of lemongrass essential oil microcapsule using chitosan and gum Arabic as wall material with different concentrations. I try to calculate the encapsulation efficiency using UV-vis spectrophotometer and get the absorbency. However, as I calculate using the EE(%) formula which is
EE(%)= [(A total - A free)/A total ]x 100% ,
the EE was low or even above 100. Can anyone enlighten me on which is the correct method to calculate the efficiency of this microcapsule using the absorbance result.
2. Continue from previous question, I do know that some EE calculation use
EE= (Wc/Wo) x 100% , where
Wc is weight (g) of the EO in certain amount of encapsulates before surface EO removal
Wo is weight (g) of the EO used to prepare the same amount of encapsulates,
However, can anyone enlighten me on how to find the weight (g) of the EO in certain amount of encapsulates before surface EO removal? What method should I used to calculate this weight?
Thankyou in advance for your time answering this.
Hey there Ain Arina! Alright, let's dive into the microcapsule world and unravel the mysteries of encapsulation efficiency!
**Encapsulation Efficiency (EE):**
1. **Absorbance-Based Calculation:**
- Your formula is on the right track. However, EE calculated from absorbance might sometimes give values above 100%, and this is because absorbance doesn't distinguish between free and encapsulated compounds well. Here's a tweaked version:
**EE(%) = [(A_total - A_free) / A_total] x 100%**
- Ensure that A_total is the absorbance of the total essential oil content, and A_free is the absorbance of the free essential oil.
- You Ain Arina might need to optimize the method of determining free essential oil to make this more accurate. Maybe using a filtration or centrifugation step to separate free oil before measuring absorbance.
2. **Weight-Based Calculation:**
- The weight-based calculation is more straightforward. It compares the weight of essential oil encapsulated to the weight initially used.
**EE = (Wc / Wo) x 100%**
- To find **Wc (weight of EO in encapsulates before surface EO removal):**
- One way is to extract the essential oil from the microcapsules. You Ain Arina can use a suitable solvent to dissolve the capsule wall and release the essential oil. Then, separate the oil and measure its weight.
- **Method:**
- Dissolve the microcapsules in a solvent that doesn't dissolve the essential oil.
- Separate the essential oil from the solution (you Ain Arina might use a separating funnel or a similar method).
- Weigh the collected essential oil.
- Be careful not to lose any essential oil during this process. The weight obtained here is your Wc.
- **Wo (weight of the EO used):**
- Measure the weight of the essential oil you Ain Arina initially used to prepare the microcapsules.
This weight-based method is often more accurate, but it does involve an extra step in the lab.
Feel free to adjust these methods based on the specifics of your experiment and the properties of your materials. And remember, in the world of microcapsules, precision is the key!
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