Skip to main content

Table 1 Analytical method characteristics

From: An inter-laboratory comparison of urinary 3-hydroxypropylmercapturic acid measurement demonstrates good reproducibility between laboratories

Laboratories 1 2 3 4
Method LC-ESI-MS/MS LC-ESI-MS/MS LC-ESI-MS/MS LC-ESI-MS/MS
mode positive negative positive negative
SPE (column) Phenomenex Strata-X Isolute ENV+ Waters OASIS Waters OASIS
SPE recovery (%) 74 68 75 78
HPLC column (make) Waters Xterra MS C18 Waters HILIC-Silica Waters Acquity Phenyl Thermo BioBasic AX
HPLC column (size) 50 × 2.1 mm, 2.5 μm 150 × 2.1 mm, 3 μm 100 × 2.1 mm, 1.7 μm 50 × 3 mm, 5 μm
Quantifier ion (mass) m/z 222 - 163 m/z 220 - 89 m/z 222 - 117 m/z 220 -91
Qualifier ion (mass) m/z 222 - 117 m/z 220 - 91   
precision intra-day (%) 1.1 to 5.9 1.4 to 8.6 1.1 to 1.5 1.2 to 6.5
precision inter-day (%) a 5.1 to 5.3 3.3 to 7 1.7 to 3.9 3.3 to 7.5
accuracy (%) 93.2 to 102 83.9 to 102 97.6 to 102 96.8 to 101
LOD (ng/ml) 2.21 NDd ND NDd
LOQ (ng/ml) 7 25 50f 35f
Linearity (ng/ml) 7 to 5400 25 to 10000 50 to 5000 35 to 5000
Matrix effect (%) ND 7.4 to 17 -1.7 to 19.6 -5.5 to 6.3
  1. aValues represent the precision range obtained for low, medium, and high concentrations at the time the methods were developed, except for Lab 1 where only low and high concentrations were tested.
  2. bBased on calibration standards.
  3. cLOD was an estimate based on spiked water, water being used as the SPE solvent.
  4. dNot determined
  5. eLOQ was established in spiked water, water being used as SPE solvent.
  6. fMatrices used were either diluted non-smoker urine or non-smoker urine with very low 3-HPMA background.