There might be some problems if there are multiple values for same concentration. In that case V Line might be the easiest option. Below is one option which should work
Pen Size(1);
For Each({val, idx}, :Concentration << Get Values,
V Line(val, 0, :Bias[idx]);
);
Edit: In some cases it might be enough to change the bar plots summary statistic to min/max. In some cases you might have to add two bar charts, one for Min and one for Max
-Jarmo