GTP Solution Absorbance Calculation
This problem requires calculating the absorbance of a GTP solution using the Beer-Lambert Law.
Beer-Lambert Law Principle
The Beer-Lambert Law relates absorbance to concentration, path length, and molar extinction coefficient. The formula is:
$ A = \epsilon \times c \times l $
Where:
- $A$ is the absorbance (unitless)
- $\epsilon$ is the molar extinction coefficient ($mol^{-1}dm^3cm^{-1}$)
- $c$ is the concentration ($mol$ $dm^{-3}$)
- $l$ is the path length (cm)
Given Values
- Molar extinction coefficient, $\epsilon = 1.55 \times 10^4$ $mol^{-1}dm^3cm^{-1}$
- Concentration, $c = 1.290 \times 10^{-5}$ $mol$ $dm^{-3}$
- Path length, $l = 1$ cm
Calculation
Substitute the given values into the Beer-Lambert Law equation:
$ A = (1.55 \times 10^4 \text{ } mol^{-1}dm^3cm^{-1}) \times (1.290 \times 10^{-5} \text{ } mol \text{ } dm^{-3}) \times (1 \text{ } cm) $
Multiply the numbers:
$ A = 1.55 \times 1.290 \times 10^{(4 - 5)} $
$ A = 1.9995 \times 10^{-1} $
$ A = 0.19995 $
Result
The calculated absorbance is $0.19995$. This value falls within the range of 0.19 to 0.2.
Important Questions from Enzyme Assays Molar Extinction Coefficient
- A solution shows a transmittance of 20% when taken in a cuvette of 2.5 cm path length. If the molar absorption coefficient of the solution is $12000 \text{ dm}^3/\text{mol.cm}$, the concentration of the solution is ________ $\times 10^5 \text{ mol/dm}^3$ (rounded off to two decimal places).
- An enzyme preparation has activity of 2 Units per 20 $\mu$l, and protein concentration 0.4 mg/ml. The specific activity (Units/mg) of this enzyme will be ________
- Measurement of the absorbance of a solution containing NADH in a path length of 1cm cuvette at 340 nm shows the value of 0.31. The molar extinction coefficient of NADH is $6200 M^{-1} cm^{-1}$. The concentration of NADH in the solution is ________ $\mu M$ (correct to integer number).
- If a $10$ mM solution of a biomolecule in a cuvette of path length $10$ mm absorbs $90\%$ of the incident light at $280$ nm, the molar extinction coefficient of the biomolecule at this wavelength is ________ $M^{-1}cm^{-1}$. (Round off to two decimal places)
- The absorbance of a $5 \times 10^{-4}$ $M$ solution of tyrosine at 280 $nm$ wavelength is 0.75. The path length of the cuvette is 1 $cm$. The molar absorption coefficient at the given wavelength in $M^{-1}cm^{-1}$, correct to the nearest integer, is ________.
