Hello ,
maybe this can sound like a strange question...

I am performing a caffein dosage in comercial coffee using a external standard .my peak(caffeein) elute in 18 minutes ,so when I inject the standard I should wait 18 minutes until the standard elute ,but I did something different, I inject my 5 standards (points) in serie (2 minutes delay )and I took the area in the same run and perform my calibration curve.
I am using a isocratic elution of course.

since the peaks area are well resolved and I donīt have (theoretically) any interaction between the standard injections ,is this a secure way to save time ?in my lab everybody says that I should inject the standard wait until it elute and inject the next.

I wait for opinions.
FAbiano

Depending on the regulations that your lab needs to comply with, technically, this can be a justified approach as long as you have validated the method to ensure that there are no interferences.

Since there are no other peaks (which allow you to do this in this manner), why not just adjust the conditions so the peak elutes in just a few minutes, and run the samples "normally"?

I canīt ,my samples are very complex and the caffein peak is the last to elute ,if I change my mobile phase the resolution become worst.

Fabiano, I think your procedure can work.
But if you have doubts you can compare both methods, the yours and the recommended by the others in your lab. You can answer yourself with the experiment.