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Determination of Nitrofurans in Milk
Using 60mg 3mL HyperSep Retain PEP
(Part Number: 60107-203)
Sample Preparation
To 15mL of milk add
1 x 2mL trichloroacetic acid
1 x 1mL H
2
O
Centrifuge at 4,000rpm
Remove supernatant for analysis
Condition HyperSep Retain PEP Extraction Column
1 x 5mL CH
3
OH
1 x 5mL H
2
O
Apply Sample
Load sample at 1 to 2mL/minute
Wash Column
1 x 10mL H
2
O
Elute Nitrofurans
1 x 5mL ethylacetate of 5mL Collect eluate at 1 to
2mL/minute
Evaporation
Evaporate eluates under a gentle stream of nitrogen <40°C
Analysis
Reconstitute sample in 1,000µL of CH
3
CN
Inject 5µL on to LC/MS
Recommended HPLC Column
Part Number
Hypersil GOLD 5µm, 100 x 2.1mm
25005-102130
Determination of Nitroimidazole Drugs and Metabolites in Royal Jelly
Using 60mg 3mL HyperSep Retain-CX
(Part Number: 60107-303)
Sample Preparation
Prepare a 100µg/mL deuterated Norfloxacin (NOR-D5)
standard in MeOH
Dilute with MeOH to a concentration of 1µg/mL
Add 5g of sample to a 50mL centrifuge tube
Add 50µL of internal standards Metronidazole (MNZ),
Dimetridazole (DMZ) and related metabolite-2 -
hydroxymethyl--1 - methyl-5–nitroimidazole
(HMMNI), Ipronidazole (IPZ) and related metabolite-
2-(2-hydroxy isopropyl)-1-methyl-5 –nitroimidazole
(IPZOH), Ronidazole (RNZ)
10mL of 0.5 mol/L sodium hydroxide solution
Mix for 15 s to dissolve the sample
Add 10mL of ethyl acetate and mix for 30 seconds
Centrifugate at 2500 r/min for 3 min
Transfer the supernatant ethyl acetate layer to a 50mL
glass test tube
Add 10mL of ethyl acetate again and repeat the
extraction procedures
Combine the ethyl acetates and evaporate to dryness by
rotary evaporator in water bath at 40°C
Dissolve the residue with 5mL of ACN containing
10% formic acid
Condition HyperSep Retain-CX Extraction Column
1 x 3mL CH
3
OH
1 X 3mL H
2
O
Apply Sample
Load sample at 1 to 2mL/minute
Wash Column
1 x 3mL H
2
O
Dry column (5 minutes at >10"Hg)
Elute Nitroimidazole
1 x 3mL of CH
3
OH
Collect eluate at 1 to 2mL/minute and evaporate to dryness
Analysis
Inject 25µL on to LC/MS
Flow rate: 0.20mL/minute
Mobile phase: methanol (A), 5mmol/L ammonium
acetate (B)
Recommended HPLC Column
Part Number
Hypersil GOLD 3µm, 150 x 2.1mm
25003-152130
Food Safety
Applications