The retention time (tr) and peak width (w) for compounds A and B are given after chromatographic separation using five different experimental parameters. Which chromatographic separations achieved a resolution that is desirable for quantitative analysis?

a. Separation 1: compound A: t; = 13.0 min; w = 5.0 min compound B: t; = 17.0 min; w = 6.5 min
b. Separation 3: compound A: tr = 14.0 min; w = 4.0 min
c. Separation 2: compound A: t; = 10.0 min; w = 3.0 min compound B: t; = 19.0 min; w = 3.0 min
d. Separation 4: compound A: tr = 11.0 min; w = 2.0 min compound B: tr = 16.0 min; w = 5.0 min compound B: tr = 15.0 min; w = 3.0 min
e. Separation 5: compound A: tr = 9.0 min; w = 2.5 min compound B: t; = 13.0 min; w= 4.5 min

Separation 2 has the highest resolution value which is 3, it is therefore the most desirable.

Explanation:

Note that in the given separations, the values for compound B which are missing in separation 3 were erroneously put in separation 4. These are the correct values for separations:

a. Separation 1: compound A: t; = 13.0 min; w = 5.0 min compound B: t; = 17.0 min; w = 6.5 min

b. Separation 3: compound A: tr = 14.0 min; w = 4.0 min compound B: tr = 16.0 min; w = 5.0 min

c. Separation 2: compound A: t; = 10.0 min; w = 3.0 min compound B: t; = 19.0 min; w = 3.0 min

d. Separation 4: compound A: tr = 11.0 min; w = 2.0 min  compound B: tr = 15.0 min; w = 3.0 min

e. Separation 5: compound A: tr = 9.0 min; w = 2.5 min compound B: t; = 13.0 min; w= 4.5 min

Determination of chromatographic separation that achieved a resolution that is desirable for quantitative analysis

In chromatography, the formula for Resolution (R) = 2(t­R(B)­ - t­R(A)­) / (W­B ­ + W ­A)

For separation 1 : Resolution (R) = 2(17.0 min - 13.0­ min) / (6.5min­ + 5.0min ) = 0.695

For separation 2 : Resolution (R) = 2(19.0 min - 10.0­ min) / (3.0min­ + 3.0min ) = 3

For separation 3 : Resolution (R) = 2(16.0 min - 14.0­ min) / (5.0min­ + 4.0min ) = 0.444

For separation 4 : Resolution (R) = 2(15.0 min - 11.0­ min) / (3.0min­ + 2.0min )

= 1.6

For separation 5 : Resolution (R) = 2(13.0 min - 9.0­ min) / (4.5min­ + 2.5min )

= 1.14

A chromatographic separation with a higher resolution is desirable for quantitative analysis. Since separation 2 has the highest resolution value which is 3, it is therefore the most desirable.

all eukaryotic cell have mitochondria : )

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.