“…So, there is a need for a good and fast analytical procedure to accurately measure the concentration of levofloxacin in patients' blood. Different analytical methods such as capillary electro kinetic chromatography [13][14][15][16], solid phase spectrofluorimetry [17], and high performance liquid chromatography with fluorescent or UV detection [18][19][20][21][22][23][24][25][26][27] have been developed to measure the levofloxacin concentrations in plasma, urine, bile, faeces and other biological fluids [28]. To our knowledge, so far only five studies [29][30][31][32][33] have quantified levofloxacin concentrations by LC-MS/MS; however, among these studies some studies measured levofloxacin in human urine [27], other studies used plasma samples but did not provide description on run time and the ones that did had a relatively long run time and sample preparation time.…”