Quantification of cephapirin in feces and urine collected from dairy cows 4, 6, and 8 hours after they were treated with cephapirin.

1<p>Results are given as mean±standard deviation (<i>n</i> = 3).</p>2<p>Cephapirin concentration in 4 and 6 h fecal samples are > LOD but < LOQ.</p>3<p>ND = Below LOD.</p><p>Quantification of cephapirin in feces and urine collected from dairy cows 4, 6, and 8 hours after they were treated with cephapirin.</p

UPLC-MS/MS MRM chromatograms for cephapirin (a) in a blank fecal sample (feces from a dairy cow before treated with cephapirin), (b) in blank feces spiked with cephapirin at 10LOQ, (c) in a fecal sample collected from a dairy cow 4 h after cephapirin was administered, (d) a cephapirin standard dissolved in MeOH:water (30∶70, v/v, 0.1% formic acid) (20 µg L⁻¹).

<p>UPLC-MS/MS MRM chromatograms for cephapirin (a) in a blank fecal sample (feces from a dairy cow before treated with cephapirin), (b) in blank feces spiked with cephapirin at 10LOQ, (c) in a fecal sample collected from a dairy cow 4 h after cephapirin was administered, (d) a cephapirin standard dissolved in MeOH:water (30∶70, v/v, 0.1% formic acid) (20 µg L⁻¹).</p

Chromatographic conditions.

1<p>A: 0.1% formic acid in water.</p>2<p>B: 0.1% formic acid in methanol.</p><p>Chromatographic conditions.</p

Linearity of standard curve for cephapirin standards dissolved in MeOH:water (30∶70, v/v, 0.1% formic acid) at concentrations ranging from 1 to 500 µg L⁻¹.

<p>Linearity of standard curve for cephapirin standards dissolved in MeOH:water (30∶70, v/v, 0.1% formic acid) at concentrations ranging from 1 to 500 µg L⁻¹.</p

MS/MS operating conditions.

<p>MS/MS operating conditions.</p

UPLC-MS/MS MRM chromatograms for cephapirin (a) in a blank urine sample (urine from a dairy cow not treated with cephapirin), (b) in blank urine spiked with cephapirin at 10LOQ, (c) in a urine sample collected from a dairy cow 4 h after cephapirin was administrated.

<p>UPLC-MS/MS MRM chromatograms for cephapirin (a) in a blank urine sample (urine from a dairy cow not treated with cephapirin), (b) in blank urine spiked with cephapirin at 10LOQ, (c) in a urine sample collected from a dairy cow 4 h after cephapirin was administrated.</p

Calibration curves of standards prepared (a) in blank fecal matrix and solvent [MeOH:water (30∶70, v/v, 0.1% formic acid)]; (b) in blank urine matrix and solvent.

<p>Calibration curves of standards prepared (a) in blank fecal matrix and solvent [MeOH:water (30∶70, v/v, 0.1% formic acid)]; (b) in blank urine matrix and solvent.</p

Daily urinary excretion of cephapirin (mg) in dairy cows administered with cephapirin (300 mg/quarter) via intramammary route.

<p>Data is represented as least square means with error bars as standard errors. Symbol * indicates that day 1 is significantly (<i>P</i><0.05) different from all other days.</p

Solid phase extraction conditions.

1<p>Flow rate was ∼3 mL/min for washing and elution steps.</p><p>Solid phase extraction conditions.</p

Method validation data.

1<p>LOQ and LOD: <b>µ</b>g kg⁻¹ wet feces or <b>µ</b>g L⁻¹ urine.</p>2<p>Recoveries are given as mean±standard deviation (<i>n</i> = 3).</p>3<p>Intra-day variation was calculated using six replicates of three spike concentrations.</p>4<p>Inter-day variation was calculated using three replicates of three spike concentrations for four days.</p><p>Method validation data.</p