The lower limit of quantification and the lower limit of detection

Lower limit of quantification (LLOQ) was defined as the lowest concentration that produced a peak area 5 times the blank solvent peak area, had an accuracy within 20% of the nominal value, and a precision of no more than 20% CV. The LLOQ of the LA was 0.07 μM (0.05 μg/mL). The LLOQ of the fragment 1, 2, 3 and 4 was 0.15, 0.16, 0.15 and 0.17 μM (0.1 μg/mL) respectively. The lower limit of detection (LLOD) was the lowest concentration that produced a peak area > 3 times blank solvent peak area. The LLOD of the LA was 0.0175 μM (0.0125 μg/mL). The LLOD of the fragment 1, 2, 3 and 4 was 0.0024, 0.0050, 0.0188 and 0.0213 μM (0.0016, 0.0031, 0.0012 and 0.0125 μg/mL) respectively.