back-calculated concentration values 怎么翻

以各个校准品的平均相对误差往后推算得出的浓度为校正范围之-1.3%至1.0%

(因中文没有单双, 可以详细些意译:
可用每个(each)校准品的平均相对误差往后推算得出其浓度, 这些(values)浓度之值为校正范围之-1.3%至1.0%)

Some problems here:

It NOT the concentration values between -1.3% to 1.0%. It should be the “mean relative errors of the concentration values” arebetween -1.3% to 1.0%.

Besides, the back-calculated concentration here means the concentration read from the calibration curve. The concentration is a bit different from the "true concentration"

I see the problem now. That is why translation of technical article requires technical knowledge. Thanks!