Sample preparation mixing

Sample preparation Mix plasma with an equal volume of MeCN, vortex for 30 s, centrifuge at 900 g for 5 min, ipject a 100 p.L aliquot of the supernatant. 

Sample preparation Mix 100 )iL plasma + 300 p.L 5 p.g/mL cefotaxime in pH 3.5 10 mM acetate buffer and keep at 4°. Inject 100 p,L onto coltunn A with mobile phase A. After 5 min backflush column A with mobile phase B onto column B for 3 min. Re-equilibrate column A with mobile phase A for 16 min. 

Sample preparation Mix an aliquot with an equal volume of 5 mg/mL cefoxitin, dilute with water, iiyect a 20 (aL aliquot. 

Sample preparation Mix urine with an equal volume of 20 mM pH 3.57 sodium acetate buffer. 500 p,L Buffered urine + 100 pL 1.5 pg/mL cephalexin -I- 150 pL 5% trichloroacetic acid, vortex for 30 s, iqject a 10 pL aliquot. 

Sample preparation Mix 1 mL plasma -1-0.1 mL 20 pg/mL IS in water, add to 1 mL Baker C-18 column, rinse twice with 1 mL water, elute with 0.5 mL MeOH. In each case passage of fluid through the column is helped by centrifugation. 

Sample preparation Mix plasma or serum with an equal volume of proteinase K, let stand for 10 min. (Alternatively, heat serum or plasma with an equal volume of 1 mg/mL subtUisin A at 50° for 15 min.) Inject 1.6 mL hydrolyzed blood or filtered serum onto column A with mobile phase A at 1 mL/min, bac ush column A with mobile phase A to waste for 2 min at 2 mL/min, backfiush the contents of column A onto column B with mobile phase B, after 30 s remove column A from the circuit, elute column B with mobile phase B, monitor the effluent from column B. (Cleem column A by backflushing with MeOH at 2 mL/min for 3 min then forward flush with water at 1 mL/min for 2 min.)... 

Sample preparation Mix 1 mL 100 jj-g/mL compound in dichloromethane with 300 pL 100 xg/mL 1-hydroxybenzotriazole in dichloromethane pyridine 99 1, 300 pL 1.1 mg/mL l-ethyl-3-dimethylaminopropylcarbodiimide hydrochloride in dichloromethane, and 300 pL 300 pg/mL benzylamine in dichloromethane, vortex, let stand at room temperature for 1.5 h, evaporate to dryness under a stream of nitrogen, reconstitute the residue in 500 pL MeOH, inject an aliquot. 

Sample preparation Mix sample with 2 mg/mL ethyl p-hydroxybenzoate in MeOH so as to give 100 pg/mL leuprolide acetate and 150 Ag/mL ethyl p-hydroxybenzoate in saline, inject a 20 p,L aliquot. 

Sample preparation Mix 20 pL of a 1 mM solution in MeOH or water with 50 pL pH 8 borate buffer and 50 pL 18 mM 2-(6-methoxy-2-naphthyl)-1-propyl chloroformate in ace-... 

Sample preparation Mix 300 pL of a 30 pM solution in dichloromethane with 10 pL 20 mM l-(6-methoxy-2-naphthyl)ethyl isothiocyanate in anhydrous dichloromethane and 50 pL 0.1% triethylamine in dichloromethane, vortex thoroughly, heat at 50° for 1.5 h, inject an aliquot. (Synthesize l-(6-metho -2-naphthyl)ethyl isothiocyanate as follows (protect from light). Dissolve 500 mg (S)-(+)-naproxen in 50 mL dry toluene, slowly add 5 mL freshly distilled thionyl chloride, reflux for 1 h, evaporate to dryness under vacuum, dry the acyl chloride (mp 87.5°) under vacuum over KOH for 2 days. Dissolve 0.5 mmoles acyl chloride in 5 mL acetone, stir at 0°, add 0.6 mmoles sodium azide dissolved in ice water, stir at 0° for 30 min, add 10 mL ice-cold water, filter, dry solid in a desiccator under vacuum. Dissolve the solid in 1 mL toluene or dichloromethane (dried over 3 A molecular sieve), reflux for 10 min, evaporate, store resulting isocyanate (mp 51°) under vacuum over a desiccant. Dissolve 0.5 mmole isocyanate in 5 mL acetone, add 20 mL 8.5% phosphoric acid, heat to 80° for 1.5 h, adjust to pH 13, extract with diethyl ether dichloromethane 4 1. Wash the organic layer twice with water, dry over anhydrous sodium sulfate, evaporate to dryness, dissolve in 1 mL toluene, evaporate to give the amine from... 

Sample preparation Mix plasma with sodium carbonate solution and extract twice with 3 mL dichloromethane. Remove the organic layer and evaporate it to dryness, reconstitute the residue in 100 p,L mobile phase, iiyect a 40 p-L aliquot. 

Sample preparation Mix 40 p,L enzyme reaction mixture with 200 aL MeCN, add 200 aL of a 20 tg/mL solution of re-propyl paraben, centrifuge, inject a 30 aL aliquot of the supernatant. 

Sample preparation Mix 1 g of a topical product, 5 mL 100 mM pH 4 citrate buffer saturated with NaCl, and 10 mL ethyl acetate, shake vigorously by hand to ensure that no large clumps stick to the tube, mix with the tube on its side on an oscillating shaker for 15 min. Remove the upper ethyl acetate layer and wash with citrate buffer as before. Dry the ethyl acetate over anhydrous sodium sulfate and evaporate to dryness. Dissolve the residue in a mixture of 10 mL heptane and 5 mL MeCNiwater 90 10. Remove the upper heptane layer and extract it with 2 mL MeCNrwater 90 10. Combine the MeCN/water layers and evaporate them to dryness, dissolve the residue in 300 pL MeOH, Alter (0.45 pm nylon), inject a 5 pL aliquot. 

Sample preparation Mix 500 itL microsomal incubation with 1 mL 200 mM pH 4 sodium acetate buffer, centrifuge, inject an aliquot. 

Sample preparation Mix 250 tL plasma with 50 p,L MeOH, add 100 p,L 2 p,gfmL IS in MeOH, add 250 p,L 1 M NaOH, add 3 mL hexaneiethyl acetate 50 50, shake at high speed for 25 min, centrifuge at 3000 g for 15 min. Evaporate the organic layer to dryness under a stream of air, reconstitute the residue with 1 mL initial mobile phase, inject a 20 xL aliquot. 

Sample preparation Mix 2 mL plasma or urine with 2 ml, 200 mM pH 7.0 phosphate buffer, extract twice with 10 mL portions of ethyl acetate. Evaporate the organic layer to dryness under a stream of nitrogen, reconstitute the residue with 60 p,L DMSO, mix, sonicate, inject a 40 jiL ahquot. 

Sample preparation Mix plasma with 5 vol of MeOH, cool to -20°, centrifuge at 4°, evaporate the supernatant to dr3mess under reduced pressure, reconstitute the residue with MeCNilO mM ammonium acetate 40 60 containing 1% acetic acid, inject an aliquot. Mix 1 mL ( ) microsomal incubation with 1.5 mL ice-cold EtOH, cool at <5° for 1 h, centrifuge, evaporate the supernatant to dr5Uiess under reduced pressure, reconstitute the residue with MeCNilO mM ammonium acetate 40 60 containing 1% acetic acid, inject an aliquot. Dilute bile twofold with 10 mM ammonium acetate, centrifuge, inject an aliquot. 

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