Question

ADCs digitize at different rates. What conversion rate is required if a chromatographic peak is to be sampled and digitized 25 times between the first positive deflection from the baseline until the peak returns to the baseline? The total baseline-to-baseline time is (a) $20\mathrm{s}$ and (b) $1\mathrm{s}$.

Short answer

Part (a) The required conversion rate is 1.25 Hz

Part (b) The required conversion rate is 25 Hz

Step-by-step solution

Part (a) Step 1. Given information

The baseline time is 20 s

The number of times the signal is to be sampled and digitized from baseline to baseline points is 25 points

Step 2. Calculation

The time required for each point is = $\frac{\text{total\hspace{0.17em}time\hspace{0.17em}required}}{\text{total\hspace{0.17em}points}}$

localid="1645656344492" $=\frac{\mathrm{20\hspace{0.17em}}s}{\text{25\hspace{0.17em}points}}=0.8\text{\hspace{0.17em}s/}\hspace{0.17em}\mathrm{point}s$

The conversion rate is localid="1645656451051" $\text{=}\frac{1}{0.8\text{\hspace{0.17em}\hspace{0.17em}points/s\hspace{0.17em}}}=1.25\text{\hspace{0.17em}Hz}$

Therefore, the required conversion rate is 1.25 Hz

Part (b)  step 1. Given information

The baseline time is 1 s

The number of times the signal is to be sampled and digitized from baseline to baseline points is 25 points

step 2. Calculation

The time required for each point is = $\frac{\text{total\hspace{0.17em}time\hspace{0.17em}required}}{\text{total\hspace{0.17em}points}}$

localid="1645656390524" $=\frac{1\hspace{0.17em}s}{\text{25\hspace{0.17em}points}}=0.04\text{\hspace{0.17em}s/}\hspace{0.17em}\mathrm{point}s$

The conversion rate is localid="1645656477774" $\text{=}\frac{1}{\text{0.04\hspace{0.17em}\hspace{0.17em}points/s\hspace{0.17em}}}=25\text{\hspace{0.17em}Hz}$

Therefore, the required conversion rate is 25 Hz