Table 1:
List of the sample preparation methods used in CE-MS analysis of liquid food
| Sample Type |
Target Compounds |
Extraction Method |
Extraction Protocol | CE-MS Conditions | Ref |
|---|---|---|---|---|---|
| Rabbit serum | Whey proteins (β-lactalbumin, Lactoglobulin A, Lactoglobulin B, Bovine serum Albumin, Casein Lactoferrin, Ribonuclease A) | No pretreatment | N/A, except matrix effect was evaluated using 1 mL of 10 times-diluted serum added to 48 mL of glycerol–H2O containing 0.5 mL Pharmacia Biotech ampholine (pH 4–6) and 0.5 mL Beckman ampholyte (pH 3–10) | CIEF: bare fused-silica capillary (80 or 100 cm length, 50 μm i.d., 375 μm o.d.) BGE: 1% (v/v) ampholyte mixture (pH 3-10) (1% v/v) and 1% (v/v) ampholine mixture (pH 4-6) in 30: 70 (v/v) glycerol: H2O. Anolyte: 1 mM glutamic acid/50 mM formic acid in glycerol:H2O medium; Catholyte: 1 mM lysine/100 mM ammonia. Focusing: +30 kV for 16 min. Mobilization: cathodic (50 mbar pressure), constant voltage at +30 kV. SL:1% formic acid in 80:20 (v/v) MeOH/H2O; 6 μL/min; ESI-MS: Positive +4.5 kV; SC: DGT 350 °C, NGT 100 °C, NP: 55 kPa | 22 |
| Honey | Endocrine disruptors (4-t-BP, 4-t-BBA, BPA, PCP 2,4,5-TCP, 2,4-DCP) | RAM and SPE | RAM: 4 mL of honey injected in RAM (pump A). At 10 min, RAM set-up to elution and analyte collected in MeOH using pump B. SPE: Oasis HLB cartridge preconditioned with 5 mL AcOET, 5 mL ACN, 5 mL H2O. About ~3.5 mL of sample loaded and cartridge dried (15 min vacuum @ 15 mmHg). Elution with 0.5 mL ACN and 3 mL AcOET. Evaporate to dryness, reconstitute in 60/40 % MeOH/H2O |
CZE: Bare fused silica capillary (75 μm i.d), BGE: 15 mM NH4OAc, pH 11.0. Injection and voltage: 15 mbar,17s,+22kV. SL: 3% (v/v) NH4OH in MeOH, 0.78 mL/min; ESI-MS: Negative, −4.0 kV SC: ESI −4000 V; DGF: 2 L/min; DGT: 100 °C; NP: 2 psi |
66 |
| Chili tomato sauce | Sudan dyes (Sudan I Sudan II Sudan III Sudan IV) | LLE | 1.0 g sample mixed with 10 mL of (3:2:1, v/v/v) acetone/DCM/MeOH, vortexed (2 min), sonicated (5 min), and centrifuged (5 min @10000 rpm). Supernatant dried, residue suspended (1 mL of acetone containing IS), and diluted (50:50 (v/v) 60 mM NH4HCO3 / 50 mM SDS + 30% ACN) | MEKC: Uncoated fused silica capillary (80 cm length, 50 μm i.d). BGE: 40 mM NH4HCO3 + 25 mM SDS + 32.5% (v/v) ACN (pH 8.0). Injection and voltage: 0.5 psi, 6s; +25 kV. SL: 0.1% formic acid in 50: 50 IPA/H2O, 4 μL/min. ESI-MS: Positive, + 4.5 kV. SC: DGF: 4 L/min; DGT: 200 °C; NP: 4 psi | 89 |
| Vegetable oils | Non-protein AAs (Ornithine, b-alanine, GABA, Alloisoleucine, Citrulline, Pyroglutamic acid) | LLE | 40 g of oils extracted with 160 mL of MeOH/CHCl3 (2:1 v/v) and left at −20 °C overnight. Centrifuged (15 min @ 4000 x g, 4°C) and upper phase washed with 40 mL CHCl3 and 100 mL H2O. Aqueous phase dried (80°C) and derivatized with butanol before injection | CZE: Uncoated fused-silica capillary (50 μm id with 60 cm of length). BGE: 0.1 M formic acid (pH 2.0). Injection and voltage: 50 mbar, 50s; +25 kV. SL: 0.1% formic acid in 50:50 IPA/H2O, 3.3 μL/min; ESI-MS: Positive, +4.5 kV. SC: DGF: 3 L/min; DGT: 300 °C; NP: 2 psi | 105 |
| Vegetable oil | Betaines (Proline betaine, Glycine betaine, Carnitine, Rigonelline) | LLE | 40 g of oils extracted with 160 mL of 2:1 (v/v) MeOH/CHCl3 and left at −20 °C (overnight). Mixture centrifuged (15 min @ 4000 x g, 4°C) and upper phase washed with 40 mL CHCl3 and 100 mL H2O using centrifugation. Aqueous phase dried at 80°C and derivatized with ButOH before injection | CZE: Uncoated fused-silica capillary, 50 μm id, total length of 60 cm. BGE: 0.1 M formic acid (pH 2.0). Injection and voltage: 50 mbar 50 sec, +25 kV. SL: 0.1% FA in 50:50 IPA/H2O, 3.3 μL/min. ESI-MS: Positive, +4.5 kV; SC: ESI +4.5kV DGF: 3 L/min; DGT: 300 °C; NP: 2 psi | 106 |
| Honey | Endocrine disruptors | LLE and QuEChERS | LLE: 9.0 mL of n-hexane added to the spiked diluted honey and centrifuged (10 min @ 3900 RCF). Upper organic phase dried (N2 at 40 °C), reconstituted [300 μL of an aq. solution 14%(v/v) MeOH and 1%(v/v) of 28% (w/w) NH4OH solution], vortex and filtered (0.45-μm cellulose filter) collected directly in 100 mL CE vial. QuEChERS: 10mL spiked-diluted honey placed in centrifuge tubes containing a mixture of salts accompanying in the kit and centrifuged (10 min @ 3000 RCF). 1 mL of the upper aqueous-organic phases cleaned with PSA supplied with the kit by centrifugation (1 min @ 3000RCF) and dried. Reconstituted as explained in the LLE procedures | CZE: Fused-silica capillaries (100 or 50 μm id) with a total length of 87 cm to MS, 20 cm to the UV. BGE: 15 mM NH4OAc (pH 11.0 adjust with 28% w/w NH4OH); Injection and voltage: 50 mbar over either 16 s or 50 s for the 100-μm id and 50-μm id capillaries, respectively; ~13.2 and 12.4% of the total capillary length, +22kV with ramp of 7s. SL: 70:30 %(v/v) IPA/MeOH, 10 μL/min. ESI-MS Negative, −4 kV; SC: DGF: 7 L/min ; DGT: 350 °C ; NP: 4 psi | 73 |
| Japanese sake (wine) | Metabolites (organic acids, amino acids, peptides, and sugar) | Filtration | Sake samples centrifuged (15 min @ 9,100g), filtered (5 kDa cutoff membrane filter), and analyze immediately by CE-TOFMS | CZE of cationic metabolite: fused silica capillaries (100 cm × 50 μm I.D). BGE: 1 M formic acid. BGE: 5 mM NH4OAc (pH 8.5). Injection and voltage: 5 k Pa for 30s, +30 kV. SL: 1:1 MeOH/−H2O, 0.1 μM hexakis (2, 2-difluoro-ethoxy) phosphazene. 10 uL/min, ESI-MS: +4kV. CZE of anionic metabolite: COSMO(+) capillary (110 cm × 50 μm I.D),). BGE: 50 mM NH4OAc (pH 8.5). Injection and voltage: 50 mbar, 30s, −30 kV. SL: 5 mM NH4OAc, 0.1 μM hexakis (2,2-difluoroethoxy) phosphazene, in 1:1 MeOH/H2O,10 mL/min. ESI-MS: −3.5kV. SC:DGF: 10 L/min; DGT: 300 °C; NP: 69 kPa. | 45 |
| Soy drinks | Isoflavones (Daidzin, Genistin Daidzein, Genistein Formononetin, Biochanin A, Glycitein Apigenin) | LLE | Ethanol mixed with sample (2:1) centrifuged (30 min @ 5000 rpm), filtered (0.45 μm nylon syringe filter). A 100 μL of filtrate diluted with 1.0 mL H2O and injected in CE-MS | CZE: Uncoated 75 μm capillary with a total length 57 cm to MS, 50 cm to the UV. BGE: 15 mM NH4OAc (pH 11.0 adjust with NH4OH). Injection and voltage: 50 mbar 5s, +25 kV. SL: 0.5% HOAc in 1:1 (v/v) IPA/-H2O,10 μL/min. ESI-MS:Positive, +3.5 kV; SC: ESI 3500 V; DGF: 6 L/min; DGT: 350 °C; NP: 5 psi | 102 |
| Balsamic vinegar, liquid coffee, and soft beverages | 5-hydroxy-methylfurfural | LLE | 300 mg sample dissolved in 6 mL of 1% TCA solution, vortexed (2 min), ultrasonicated (10 min), vortexed (2 min), and centrifuged (10 min @ 9000 rpm, 4 °C). Extracts filtered (0.20 mm nylon filter) and mixed with 6 mL of 500 mg/L FMK solution to obtain a concentration of 5 mg/L in a final volume of 600 μL | CZE: Untreated fused-silica capillary (50 μm i.d. and effective length of 60 cm). BGE: 50 mM formic acid (pH 3.0 adjust with 0.5 M NH4OH). Injection and voltage: 50 mbar, 10s, +25 kV.SL: 0.1% FA in 50% MeOH, 3 μL/min. ESI-MS: Positive, +3.5 kV, SC: DGF: 2 L/min; DGT: 200 °C; NP: 10 psi | 92 |
| Bovine milk | Quinolones (Danofloxacin, sarafloxacin, difloxacin, enrofloxacin, ciprofloxacin flumequine marbofloxacin oxolinic acid) | In-line SPE | 25μL acetic acid added to 5 g of bovine milk and centrifuged (9000 rpm, 10 min) for protein precipitation. 1mL of supernatant mixed with 2 mL of 50 mM NH4OAc buffer pH 5.0 and defatted by centrifuging (5 min @ 9000 rpm) with 3mL of n-hexane. 0.5mL of aqueous phase mixed with 1mL of 50 mM NH4OAc (pH 5.0), filtered, and injected | CZE: Bare fused-silica capillary of 130 cm total length ×50 μm id (360 μm od). BGE: 50 mM NH4OAc (pH 9.1 adjust with 5 M NH4OH). Injection and voltage: 2bar, 15 min, +25 kV. SL: 50:49:1 (v/v/v) IPA/H2O/FA, 3 μL/min. ESI-MS: Negative, 4kV; SC: DGF: 6 L/min; DGT: 150 °C; NP: 4 psi | 57 |
| Banana, tomato, and peach juices | Carbamate pesticides | VSLLME | 5 g of juice centrifuged (10 min @ 9509 rcf) and the supernatant collected (15 mL falcon tube). Mixture of 100 mM APFO, pH 9.0 (emulsifier, 530 μL) and CHCl3 (extraction solvent, 1300 μL) injected into the sample tube, vortexed (30 s), and centrifuged (10 min @ 9509 rcf). Sedimented organic phase removed (with syringe) and CHCl3 evaporated under N2. Residues redissolved (250 mL of 75 mM APFO pH 9.0), filtered and injected into CE | MEKC: Bare fused-silica capillary(90 cm total length, 50 μm ID, 375 μm OD. BGE: 100 mM perfluorooctanoic acid (pH 9.0 adjust with 15 M NH4OH). Injection and voltage: 50 mbar, 30 sec, +23 kV. SL: 99.9:0.1 (v/v) IPA/FA, 1.66 μL/min; ESI-MS: Negative, −4.8 kV; SC: DGF: 8 L/min; DGT: 180 °C; NP: 0.082 MPa | 13 |
| Blueberry Juice | Organic acids (succinic acid, citric acid, salicylic acid malic acid, benzoic acid sorbic acid, ascorbic acid, tartaric acid) | Filtration | Juice sample diluted with BGE (1:10), centrifuged (10,000 r/min, 25,152 g for 10 min), and filtered (0.22 μm membrane) | CZE: Bare fused-silica capillary (50 μm i.d × 70 cm). BGE: 40 mM NH4OAc (pH 6.0 adjust with 1 M HOAc), +22 kV. SL: 7.5 mM HOAc in 70:30 (v/v) IPA/H2O, 6 μL/min. ESI-MS: Positive, +4 kV; SC: ESI 4 kV; DGF: 6 L/min; DGT: 350 °C; NP: 12 psi | 108 |
| Human milk | Free nucleotide monophosphate | CUF | 1 mL of milk sample mixed with 4 mL of H2O centrifuged (15 min @ 2800g). 5-mL supernatant collected (top fat layer avoided) into the CUF device (previously conditioned with 5 mL H2O) and ultrafiltered (30 min, 2800g). Filtrate injected into the CE–ESI-MS system | CZE: Fused-silica capillaries (50 and 100 μm id) with total lengths of 87.5 to MS and 20 cm to the UV detector. Injection and voltage: 50 mbar, 30 s, +30 kV. BGE: 30 mM NH4COOH (pH 9.6). SL: 50:50 (v/v) IPA/H2O,10 μL/min ESI-MS: Negative, −4 kV, SC:; DGF: 7 L/min; DGT: 350 °C; NP: 10 psi | 112 |
| Cow milk, goat milk | Estrogenic compounds (estriol, 17α-estradiol, 17β-estradiol, estrone, 17α–etynylestradiol, mycotoxin, 2-methoxyestradiol, α-zearalanol, β-zearalanol, α-zearalenol, and β-zearalenol) | DLLME | Milk sample (centrifuged, protein extracted, and defatted) diluted to a final volume of 7.5 mL (with H2O and NaCl added to final concentration of 30% w/v) and filtered (0.45 μm PTFE filter). Mixture of 500 μL ACN (as dispersion solvent) and 110 μL CHCl3 (as extraction solvent) mixed with aqueous extract (vortex 2 min). Resulting dispersion centrifuged (4000 rpm/2500×g, 5 min) observing later a droplet of CHCl3 in the bottom layer. Upper aqueous phase (~ 4 mL partially removed) (droplet transferred to a vial, dried (N2), reconstituted (75 μL BGE) and injected | MEKC: Fused-silica capillaries 60 cm (50 μm id × 363 μm od. BGE: 45 mM ammonium perflurooctanoic acid (pH 9.0) + 10% (v/v) MeOH. Injection and voltage: 0.5 psi, 25 s, +25 kV. SL: 96:4 (v/v) IPA/H2O, 1.7 μL/min ESI-MS: SC: ESI −4.6 kV V; DGF: 3 L/min; DGT: 200 °C; NP: 3 psi | 12 |
| Honey | Aminoglycosides Gentamicin, a mixture of GENT C1, GENT C1a and GENT C2, Neomycin, Apramycin, Paromomycin, Dihydrostreptomycin, Spectinomycin, Streptomycin | SPE | 10 g of honey spiked at different levels with working standards of AGs. Samples diluted (with 19.5 mL of 50 mM K3PO4 buffer pH 7.0) and final volume adjusted to 20.0 mL (with 50 mM K3PO4 buffer pH 7.0). Aliquot (3 mL) loaded onto Supelco MIP AG SPE column (pre-conditioned with 1 mL of MeOH and 1 mL of phosphate buffer pH 7.0 at a flow rate of 0.2 mL/min), washed (3 mL H2O and 1 mL 0.1% NH4OH, flow rate <0.5 mL/min), dried (vacuum 0.8 bar, 5 min), washed (1 mL 40:60 (v/v) ACN:H2O and 1 mL 50:50, (v/v) DCM:MeOH), and dried (vacuum, 10 s). Analytes eluted with 1 mL of 1% FA in MeCN:H2O (20:80, v/v), diluted (4x with H2O), filtered, and analyzed by CZE-MS/MS method. | CZE: a bare fused-silica capillary (90 cm total length, 50 μm i.d., 375 mm o.d). BGE: 200 mM formic acid, 7 mM NH4OH (pH 2.2). Injection and voltage: 25 mbar, 90 sec at 25 kV. SL: 50:49.9:0.1 (v/v/v) MeOH/H2O/-HOAc, 2 μL/min ESI-MS: −4.0 kV; SC: ESI −4000 V; DGF: 5 L/min; DGT: 150 °C; NP: 5 psi | 62 |
| Sugarcane and tomato juices | Halosulfuron-methyl herbicides | QuEChERS | 10.0 g sample placed in 50 mL centrifuge tube with 10.0 mL of ACN, 4.0 g of MgSO4 (anhydrous), and 1.0 g of NaCl (Agilent Bond Elut QuEChERS AOAC Extraction kit – PN 5982-5755). Tube shake (1 min) and centrifuged (5 min, RCF = 1521). 500 μL supernatant diluted (500 μL BGE) filtered (0.45 μm CE membrane, Agilent P/N 5190-5284) and analyzed | CZE: 58 cm long, 50 μ m i.d., 360 μm o.d. fused-silica capillary. Injection and voltage: 100 mbar, 12s, +25 kV.BGE: 20 mM NH4HCO3 (pH 8.5 adjust with NH4OH). SL: BGE diluted 5x with 1:1 (v/v) MeOH/H2O, 6 μL/min. ESI-MS: Positive, +5kV,SC: DGF: 3 L/min; DGT: 280 °C; NP: 7 psi | 54 |
| Beer and wine | Biogenic amines Spermine, Spermidine, Putrescine, Cadaverine, Histamine, 2-Phenylethylamine, Tryptamine, Tyramine, Urocanic acid, | Simple clean-up (LLE) | Phenolic compounds and other interferents removed from 10 mL sample with 0.5 g PVPP (vortex 3 min, centrifuge 5 min at RCF = 1521). Supernatant filtered (0.45 μm CE filter, Agilent P/N 5190-5284) and analyzed | CZE: 70cm long, 50 μm i.d., 360 μm o.d. polyvinyl alchol coated capillary (Agilent Technologies). BGE: 0.5 M HOAc (pH 2.5). Injection and voltage: 50 mbar, 10s, +25 kV. SL: BGE diluted 5x with 1:1 (v/v) MeOH/H2O, 6 μL/min. ESI-MS: Positive, +4.5 kV; SC: DGF: 6 L/min; DGT: 150 °C; NP: 12 psi | 103 |
| Fermented milk | Cationic and Anionic Metabolites, peptides | LLE | Fermented milk sample centrifuged (10 min @ 15,300 x g) and 100 μL supernatant mixed with 900 μL MeOH, 1000 μL CHCl3, and 400 μL H2O. Resulting mixture centrifuged (5 min @ 2,300 x g) and aqueous phase passed through ultrafiltration membrane (5-kDa cutoff filter for 2 h @ 9,100 x g, 4°C). Filtrate dried, redissolved (25 μL H2O) and analyzed | CZE: bare fused-silica capillary (50 μm, 80 cm). BGE: commercial cation solution (H3301-1001); anion solution (I3301-1023). Injection and voltage: 50 mbar, 10 s and 50 mbar , 25 s at 25 kV and 30 kV for cation and anion analysis. SL: 5 mM NH4OAc in 50% (v/v) MeOH/H2O, 1 μM reserpine, 10 μL/min. ESI-MS:+4 kV and 3.5 kV for cation and anion analysis, respectively. SC: ESI +4000 V and −3500 V; DGF: 10 L/min DGT: 300 °C, NP: 10 psi | 100 |
| Orange juice and wine | Anionic metabolites | Filtration | Samples filtered with 0.2 μm PES filter | CZE: cationic PTH capillary coating (50 μm i.d) composed of a poly-(N,N,N’,N’-tetraethyldiethylenetriamine, N-(2-hydroxypropyl) methacrylamide, TEDETAMA-co-HPMA (50:50) copolymer. BGE:1 M FA (pH 2.4); Injection and voltage: 34.5 mbar for 80s, + or −20 kV. SL: 50:50 IPA/H2O at 0.24 mL/h. ESI-MS: Positive and negative ion mode; SC: DGF: 4 L/min; DGT: 200 °C; NP: 0.4 bar | 9 |
| Japanese sake | Organic acids | Fractionation by ion exchange | pH of sake adjusted to 6.5 (1 N NaOH) and fractioned into basic AAs, neutral and acidic AAs, OAs, and sugars using columns IRC-76, IR-120BH, and IRA-96SB. OA fractions lyophilized and dissolved in H2O to 50-fold conc. Compared to original conc. OA fraction further diluted 50 x by ND96 Ringer’s solution (pH 7) | No CZE-MS conditions specified | 107 |
| Milk | Tetracyclines and quinolones | SPE | 1 g milk mixed with 4 mL of 0.2%FA in ACN and 1 mL Mcllvaine’s buffer; pH adjusted to 4 (1 M NaOH). Mixture vortexed (10s), centrifuged (6 min @ 7500 rpm), and supernatant passed at 1 mL/min through SPE cartridge (Oasis PRIME HLB preconditioned with 3 mL 0.2% FA in ACN and 1 mL Mcllvaine’s buffer). Extracts collected, dried (N2), reconstituted (10 mL of 1 M NH4OH), and filtered | CZE: a bare fused-silica capillary (90 cm total length, 50 μm i.d., 375 μm o.d.). BGE: 75 mM NH4OAc + 2.5 mM EDTA (pH 9.0). Injection and voltage, 50 mbar, 100s at +25 kV. SL: 5 μM purine and 1.25 μM HP-0921) in 70:29.9:0.1 (v/v/v) MeOH:H2O:formic acid, , 2 μL/min. ESI-MS: Positive +5.4 kV, SC: DGF: 3 L/min; DGT: 250 °C; NP: 5 psi | 109 |
| Wine | Biogenic amines | Filtration | Wine samples ultrasonicated (15 min), filtered (0.45 μm PTFE syringe filter), and injected into CE-MS. | CZE: fused silica capillary (internal diameter 75 μm, total length 100 cm); BGE: 100 mM formic acid. Injection and voltage: 0.7 psi, 6s at +30 kV. ESI-MS: +4.5 kV; SC: DGF: 4 L/min; DGT: 180 °C; NP: 0.4 bar | 81 |
| Wine | Lactic, succinic, malic, tartaric, shikimic, and citric acids | Filtration | Wine samples diluted with H2O (1:5 ratio), filtered (0.45 μm PVDF syringe filter), and injected into CE-MS | CZE: Fused -silica, 80 or 120 cm long (50 μm id), polybrene coated capillaries. BGE: 50 mM NH4OAc (pH 6.0). Injection and voltage: 50 mbar, 2s, +20 kV. SL: 1% (v/v) formic acid, 0.7 μL/min. ESI-MS: Positive, +4.5 kV; SC: DGF: 8 L/min; DGT: 325 °C; NP: 35 psi | 10 |
| Vinegars | Chiral amino acids | Filtration | 500 μL sample filtered (3 kD cutoff filter) by centrifugation (10 min @ 14,000 g) and diluted with H2O | CZE: (50 μm i.d.×358 μm o.d., 100cm in total length). BGE: 1 M formic acid + 30 mM (+)- and (−)-(18-crown-6)-2,3,11,12-tetracarboxylic acid. Injection and voltage: 50 mbar, 10s, +24 kV. SL: 1:1 (v/v) MeOH/ H2O,0.15 μM Hexakis (HP0921) and 0.075 μM purine; 10 μL/min. ESI-MS: Positive, +4 kV; SC: DGF:12 L/min; DGT: 200 °C | 26 |
| Chili sauce | Sudan dyes | Freeze-out cleanup | 2.0 g sample mixed with 5 mL ACN and sonicated (5 min, 35 kHz, 120 W). Mixture centrifuged (5 min @ 4025×g),supernatant mixed with 2.5 mL H2O and 1 g NaCl and placed at −20 °C for 3 h. 100 μL of the ACN layer diluted to 1:10 with 900 μL of 6:1:1:1 (v/v/v/v) H2O/ ACN/MeOH/THF mixture, leading to a final dilution of 1:50. Solution filtered (0.22 μm nylon syringe filter) and assayed by MEKC/MS/MS | MEKC: BGE: 60:20:10:10 (v/v/v/v), 25 mM ammonium perfluorooctanoic acid; /ACN/MeOH/THF (pH 9.0); Injection and voltage: 5 kPa, 50s, +25 kV. SL: 50:49.9:0.1 (v/v/v) IPA/ H2O/FA, 10 μL/min. ESI-MS: +3 kVSC: DGF: 6 L/min; DGT: 250 °C; NP: 206.8 kPa | 89 |
| Dietary supplement | Nanomaterials monitored isotope (m/z): 112Cd, 197Au, 195Pt, 105Pd. | No pretreatment | Suspensions injected directly to CE-ICP-MS | MEKC: Bare fused-silica capillaries (i.d. 50 μm; o.d. 360 μm; length 67 cm). BGE: 10 mM TRIS + 70 mM SDBS (pH 9.0). Injection and voltage: 30 mbar, 5s, +30 kV. Make up liquid: 1% nitric acid, 10 % MeOH in water. ICP-MS: RF power: 1500 W; plasma gas: 15 L/min, NGF: 0.9 L/min | 122 |
CZE: capillary zone electrophoresis; CIEF: capillary isoelectric focusing; MEKC: micellar electrokinetic chromatography; ESI-MS: electrospray ionization mass specorometery; ICP-MS: inductively coupled plasma mass spectrometery; BGE: background electrolyte; SL: sheath liquid; SC: spray chamber; DGT: drying gas temperature; DGF: drying gas flow; NGT: nebulizing gas temperature; NP: nebulizer pressure; AG: aminoglycoside; PVPP: poly(vinylpolypyrrolidone); PES: polyethersulfone; OA: organic acids; EDTA: ethylenediamine tetraacetate; PSA: primary secondary amine material; FMK: 2-Furylmethylketone; NGF: nebulizer gas flow.