Multiresidue determination of sulfonamides in a variety of biological matrices by supported liquid membrane with high pressure liquid chromatography-electrospray mass spectrometry detection

A high performance liquid chromatography (HPLC) coupled to a mass spectrometer (MS) was used for a simultaneous determination of 16 sulfonamide compounds spiked in water, urine, milk, and bovine liver and kidney tissues. Supported liquid membrane (SLM) made up of 5% tri-n-octylphosphine oxide (TOPO) dissolved in hexyl amine was used as a sample clean-up and/or enrichment technique. The sulfonamides mixture was made up of 5-sulfaminouracil, sulfaguanidine, sulfamethoxazole, sulfamerazine, sulfamethizole, sulfamethazine (sulfadimidine), sulfacetamide, sulfapyridine, sulfabenzamide, sulfamethoxypyridazine, sulfamonomethoxine, sulfadimethoxine sulfasalazine, sulfaquinoxaline, sulfadiazine, and sulfathiazole. Some of these compounds, such as, sulfaquinoxaline, sulfadiazine, sulfabenzamide, sulfathiazole and sulfapyridine failed to be trapped efficiently by the same liquid membrane (5% TOPO in hexylamine). The detection limits (DL) obtained were 1.8 ppb for sulfaguanidine and sulfamerazine and between 3.3 and 10 ppb in bovine liver and kidney tissues for the other sulfonamides that were successfully enriched with SLM; 2.1 ppb for sulfaguanidine and sulfamerazine and between 7.5 and 15 ppb in cow’s urine, whereas the DL values in milk were 12.4 ppb for sulfaguanidine and sulfamerazine and between 16.8 and 24.3 for the other compounds that were successfully enriched by the membrane. Several factors affecting the extraction efficiency during SLM enrichment, such as donor pH, acceptor pH, enrichment time and the membrane solvent were studied.     

Dispersive solid-phase extraction for the determination of sulfonamides in chicken muscle by liquid chromatography

A new, fast and low-cost sample preparation for the determination of sulfonamide (SA) residues in chicken muscle by LC technique has been developed. The procedure involves single extraction of sample with acetonitrile, followed by a rapid clean-up and was called "dispersive solid-phase extraction" (dispersive SPE). Using dispersive SPE 25 mg of octadecyl sorbent was added to 1 ml of acetonitrile extract, mixed and centrifuged. The acetonitrile layer was evaporated and residue was dissolved in acetate buffer (pH 3.5). Analysed compounds were detected by fluorescence detector after pre-column derivatization with fluorescamine. The separation of analytes was performed with gradient elution with mobile phase methanol: 2% acetic acid and RP-LC analytical column. The whole procedure was evaluated for six sulfonamides (sulfadiazine, sulfamerazine, sulfamethazine, sulfametoxypirydazine, sulfametoxazole and sulfadimetoxine) according to the European Commission Decision 2002/657/EC. Specificity, decision limit (CCalpha), detection capacity (CCbeta), trueness and precision were determined during validation process. The dispersive SPE with octadecyl sorbent was found suitable for sample preparation before sulfonamide determination in chicken muscle. As it was found the most of endogenous matrix components were removed and the analytes were isolated from spiked samples with recoveries above 90%. The used analytical conditions allow to successively separate all the tested sulfonamides with the limit of detection at the level of 1-5 microg/kg. The method is simple, rapid and more effective than conventional methods.     

Matrix solid-phase dispersion extraction of sulfonamides from blood

Matrix solid-phase dispersion extraction was applied to the extraction of sulfadiazine, sulfamerazine, and sulfamethazine from human and animal bloods. The separation and determination of the analytes were carried out by high-performance liquid chromatography. The effects of the types of the dispersion adsorbents and elution solvents were investigated, and the highest recovery was obtained when diatomaceous earth was used as the dispersion adsorbent, while acetone was used as the elution solvent. Under the optimal conditions, the linear range for determining the sulfonamides in blood samples was 0.020-10.0 μg/mL, and the average recoveries of the three sulfonamides were higher than 87.5%.     

Optimization of a FIA system with amperometric detection by means of a desirability function: determination of sulfadiazine, sulfamethazine and sulfamerazine in milk

A sensitive and cheap FIA, with amperometric detection, analytical procedure is developed in this paper to determine sulfadiazine, sulfamethazine and sulfamerazine in milk. A multicriteria optimization based on the use of a desirability function is used for optimizing two analytical responses (peak height and its variability) since single-objective optimizations lead to conflicting experimental conditions. In the optimum conditions, the determination of the three sulfonamides in milk samples is carried out, the analytical procedure being validated according to Commission Decision 2002/657/EC. The decision limit at 0 and 100 microg L(-1) (which is the maximum residue limit in milk) are 13.9 and 110.2, 9.5 and 107.1 and 9.1 and 107.1 microg L(-1) for sulfadiazine, sulfamethazine and sulfamerazine, respectively. Whereas the values of capability of detection, CCbeta, obtained at 0 and 100 microg L(-1) were 26.9 and 119.8, 18.2 and 113.6, and 17.5 and 113.7 microg L(-1) for sulfadiazine, sulfamethazine and sulfamerazine, respectively. Recovery values between 67.4% and 119.1% are found for milk test samples of two brands of milk. The accuracy of the method is confirmed. The ruggedness of the procedure is evaluated by means of a Plackett-Burman design. The relative errors were lower than 2.5% (n=7).     

Polypyrrole/silica/magnetite nanoparticles as a sorbent for the extraction of sulfonamides from water samples

A magnetic solid‐phase extraction sorbent of polypyrrole/silica/magnetite nanoparticles was successfully synthesized and applied for the extraction and preconcentration of sulfonamides in water samples. The magnetite nanoparticles provided a simple and fast separation method for the analytes in water samples. The silica coating increased the surface area that helped to increase the polypyrrole layer. The polypyrrole‐coated silica provided a high extraction efficiency due to the π–π and hydrophobic interactions between the polypyrrole and sulfonamides. Several parameters that affected the extraction efficiencies, i.e. the amount of sorbent, pH of the sample, extraction time, extraction temperature, ionic strength, and desorption conditions were investigated. Under the optimal conditions, the method was linear over the range of 0.30–200 μg/L for sulfadiazine and sulfamerazine, and 1.0–200 μg/L for sulfamethazine and sulfamonomethoxine. The limit of detection was 0.30 μg/L for sulfadiazine and sulfamerazine and 1.0 μg/L for sulfamethazine and sulfamonomethoxine. This simple and rapid method was successfully applied to efficiently extract sulfonamides from water samples. It showed a high extraction efficiency for all tested sulfonamides, and the recoveries were in the range of 86.7–99.7% with relative standard deviations of < 6%.     

One‐pot synthesis of a multi‐template molecularly imprinted polymer for the extraction of six sulfonamide residues from milk before high‐performance liquid chromatography with diode array detection

A highly selective molecularly imprinted polymer sorbent was synthesized and employed for the simultaneous determination of six sulfonamide antibiotic residues (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfamerazine, and sulfamethizole) in milk samples. Multi‐analyte imprinted particles were used as a sorbent in solid‐phase extraction. Sulfonamides were separated on a high‐performance liquid chromatography column (Merck–Lichrospher RP18e, 5 μm 250 × 4 mm) and further identified and quantified by diode array detection. Several parameters including required loading of the molecularly imprinted polymer sorbent, mass of milk, volume, and type of elution solvent, as well as time for absorption and elution were investigated to obtain optimal experimental conditions. For comparison purpose, a non‐imprinted polymer was applied under the optimum conditions. The validation study according to the European Union Decision 2002/657/EC was based on the investigation of linearity, selectivity, stability, limits of detection and quantitation, decision limit, detection capability, trueness, precision, and ruggedness according to Youden's approach. The decision limit and detection capability values in the milk were achieved from 101.9 to 113.5 μg/kg and from 114.4 to 135.4 μg/kg, respectively, depending on the target sulfonamide drug. Finally, the optimized protocol was successfully applied to commercial milk samples and human breast milk.     

Simple and rapid determination of sulfonamides in milk using Ether-type column liquid chromatography

A simplified and rapid determining/identifying method for residual sulfonamides (SAs) in milk by using Ether-type stationary phase, which made in our lab, was presented. The target analytes were extracted by mixing with ethanol-acetic acid (97:3, v/v) followed by centrifugation. The procedure used a Ether-type C8 column, isocratic elution with acetonitrile-water (5:95, v/v), and a photo-diode array detector. The linear range of determination was 50-10,000 μg/L for sulfanilamide and 100-10,000 μg/L for sulfadiazine, sulfamerazine, sulfamethazine. Average recoveries of four SAs (spiked 0.5, 1.0 and 1.5 μg/mL) ranged from 80.1% to 87.6%, with relative standard deviations between 3.4% and 5.8%. The total time and solvent required for the analysis of one sample were <15 min and <1.0 mL of ethanol and 0.6 mL of acetonitrile, respectively. The developed procedure was nearly harmless to the human and environment.     

Room temperature fabrication of magnetic covalent organic frameworks for analyzing sulfonamide residues in animal-derived foods

A magnetic solid phase extraction method based on magnetic covalent organic frameworks (TpBD@Fe₃O₄; 2,4,6-triformylphloroglucinol (Tp) and benzidine (BD)) combined with high performance liquid chromatography has been developed to detect the sulfonamides including sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole in milk and meat. TpBD@Fe₃O₄ were synthesized at room temperature under mild reaction conditions with a simple and rapid operation. The TpBD@Fe₃O₄ exhibited higher extraction efficiency because of the π–π and electrostatic interactions between the benzene ring structure of the TpBD and the sulfonamide molecules. The extraction conditions including the dosage of adsorbents, the type and dosage of eluent, the elution time, and the pH of the sample solution were fully optimized. The detection results showed good linearity over a wide range (50–5 × 10⁴ ng/mL) and low detection limits (3.39–5.77 ng/mL) for the sulfonamide targets. The practicability of this magnetic solidphase extraction-high-performance liquid chromatography method was further evaluated by analyzing milk and meat samples, with recoveries of the targets of 71.6–110.8% in milk and 71.9–109.7% in pork. The successful detection of sulfonamides residues has demonstrated the TpBD@Fe₃O₄ excellent practical potential for analyzing pharmaceutical residues in animal-derived foods.     

Voltammetric detection of sulfonamides at a poly(3-methylthiophene) electrode

Detection of sulfonamide compounds in a mixture of standards at a poly(3-methylthiophene) coated on glassy carbon (GC) electrode is reported. The polymer, poly(3-methylthiophene), was electrochemically synthesized at a GC rotating disk-working electrode versus Ag/AgCl using cyclic voltammetry (+0.5 to +2.0 V). Square wave voltammetry (SQWV) with cathodic reduction (0 to -4.0 V) was used for the detection of seven sulfonamide compounds in a mixture. The working concentration ranges (curvilinear) established for different compounds in Britton-Robinson (BR) buffer (pH 6.26), were: 5.0x10(-6)-3.2x10(-3) M sulfamerazine, 5.0x10(-6)-3.2x10(-3) M sulfadiazine, 7.5x10(-7)-3.2x10(-4) M sulfasalazine, 9.0x10(-7)-5.0x10(-4) M sulfamethazine, 6.5x10(-8)-3.5.0x10(-5) M sulfamethoxazole, 9.7x10(-8)-5.0x10(-5) M sulfathiazole, and 9.0x10(-8)-3.2x10(-5) M 5-sulfaminouracil. Detection limits were calculated as: 3.9x10(-6) M for sulfamerazine; 4.0x10(-6) M sulfadiazine; 2.5x10(-7) M sulfasalazine; 3.7x10(-7) M sulfamethazine; 4.0x10(-8) M sulfamethoxazole; 6.4x10(-8) M sulfathiazole and 6.0x10(-9) M 5-sulfaminouracil. The data suggests a potential application of the poly(3-methylthiophene) (P3MT) electrode for determination of sulfonamides in veterinary and other applications.     

Rapid determination of sulfonamides in milk samples using fluorescence spectroscopy and class modeling with n-way partial least squares

In this paper, a methodology to evaluate the probability of false non-compliance and false compliance for screening methods, which give first or second-order multivariate signals is proposed. For this task 120 samples of 6 different kinds of milk have been measured by excitation-emission fluorescence. The samples have been spiked with different amounts of three sulfonamides (sulfadiazine, sulfamerazine and sulfamethazine). These substances have been classified in group B1 (veterinary medicines and contaminants) of annex I of Directive 96/23/EC. The European Union (Commission Regulation EC no. 281/96) has set the maximum residue level (MRL) of total sulfonamides at 100 μg kg⁻¹ in muscle, liver, kidney and milk.The work shows that excitation-emission fluorescence together with the partial least squares class modeling (PLS-CM) procedure may be a suitable and cheap screening method for the total amount of sulfonamides in milk. Three models, PLS-CM, have been built, for the emission and excitation spectra (first-order signals) and for the excitation-emission matrices (second-order signals). In all the cases it reaches probabilities of false compliance below 5% as required by Decision 2002/657/EC.With the same flourescence signals, the total quantity of sulfonamide was calibrated using 2-PLS, 3-PLS and PARAFAC regressions. Using this quantitative approach, the capability of detection, CCβ, around the MRL has been estimated between 114.3 and 115.1 μg kg⁻¹ for a probability of false non-compliance and false compliance equal to 5%.     

Novel capsule phase microextraction in combination with high performance liquid chromatography with diode array detection for rapid monitoring of sulfonamide drugs in milk

Capsule phase microextraction is introduced herein for the first time to determine four sulfonamide residues in milk samples (sulfanilamide, sulfadiazine, sulfamethizole, and sulfathiazole). The technique eloquently integrates filtration and stirring mechanism into the extraction device, as such no filtration of the sample is needed prior to introducing the extraction device into the sample, and when placed on a magnetic stirrer, the device spins itself in order to diffuse the sample, resulting in faster extraction equilibrium. Microextraction capsules consist of three main parts; a magnet, a cellulose fiber substrate coated with high performance sol‐gel hybrid organic‐inorganic sorbent, and a porous membrane. Various encapsulated sol‐gel sorbents were tested in standard solutions prepared in deionized water and milk samples under different operational conditions. Analyte extraction time and elution time, type of sol‐gel sorbent, elution solvent, as well as the ratio of the sorbent to the elution solvent were among the optimized conditions. The protocols that yielded the best absolute recovery rates were subsequently tested in various milk samples. Method validation was performed in terms of linearity, accuracy and precision, reusability and ruggedness using the Youden test. The examined sulfonamides were subsequently analysed by reversed phase high performance liquid chromatography with diode array detection.     

A new and simple method to determine trace levels of sulfonamides in honey by high performance liquid chromatography with fluorescence detection

A novel method for the simultaneous analysis at trace level of sulfonamides (sulfaguanidine, sulfanilamide, sulfacetamide, sulfathiazole, sulfapyridine, sulfachloropyridazine, sulfamerazine, sulfameter, sulfamethazine, sulfadoxine, sulfadiazine, sulfamonomethoxine, sulfadimethoxine) in honey is described. Methanol has been used in the sample treatment step to avoid the emulsion formation and to break the N-glycosidic bond between sugars and sulfonamides. The determination is carried out by liquid chromatography in gradient elution mode, with fluorescence detection after the on-line pre-column derivatization with fluorescamine. The influence of parameters such as the mobile phase composition, column temperature, pH or injection volume, on the separation has been taken into account and the derivatization step has also been optimized. Recoveries of the compounds on spiked honey samples ranged from 56% for sulfadoxine to 96% for sulfacetamide, with relative standard deviations below 10%. The quantitation limits are between 4 and 15 ng g⁻¹.     

Application of Micellar Mobile Phase for Quantification of Sulfonamides in Medicated Feeds by HPLC-DAD

Rapid chromatographic procedure for quantification of five sulfonamides in medicated feeds are proposed. Satisfactory separation of sulfonamides from medicated feeds was achieved using a Zorbax Eclipse XDB C18 column (4.6 × 150 mm, 5 µm particle size) with a micellar mobile phase consisting of 0.05 M sodium dodecyl sulphate, 0.02 M phosphate buffer, and 6% propan-2-ol (pH 3). UV quantitation was set at 260 nm. The proposed procedure allows the determination of sulfaguanidine, sulfadiazine, sulfamerazine, sulfamethazine, and sulfamethoxazole in medicated feeds for pigs and poultry. Application of the proposed method to the analysis of five pharmaceuticals gave recoveries between 72.7% to 94.7% and coefficients of variations for repeatability and reproducibility between 2.9% to 9.8% respectively, in the range of 200 to 2000 mg/kg sulfonamides in feeds. Limit of detection and limit of quantification were 32.7–56.3 and 54.8–98.4 mg/kg, respectively, depending on the analyte. The proposed procedure for the quantification of sulfonamides is simple, rapid, sensitive, free from interferences and suitable for the routine control of feeds. In the world literature, we did not find the described method of quantitative determination of sulfonamides in medicated feeds with the use of micellar liquid chromatography.     

Determination of 10 sulfonamide residues in meat samples by liquid chromatography with ultraviolet detection

A liquid chromatography (LC) method is described for the simultaneous determination of 10 commonly used sulfonamide drug residues in meat. The 10 sulfonamide drugs of interest were sulfadiazine, sulfathiazole, sulfamerazine, sulfadimidine, sulfamethizole, sulfamonomethoxine, sulfachloropyridazine, sulfadoxine, sulfadimethoxine, and sulfaquinoxaline. The residues were extracted with acetone-chloroform (1 + 1). Sulfonamides were quantitatively retained in the extracting solution and afterwards eluted from a cation-exchanger solid-phase extraction cartridge with a solution of methanol-aqueous ammonia. The solution was dried, reconstituted with 5 mL methanol and filtered before analysis by LC-ultraviolet using a C18 column with a mobile phase gradient of potassium dihydrogen phosphate buffer, pH 2.5, and methanol-acetonitrile (30 + 70, v/v). The method was applied to cattle, swine, chicken, and sheep muscle tissues. The validation was performed with a fortified cattle meat sample at level of 100 ppb, which is the administrative maximum residue limit for sulfonamides in the European Union. The limit of quantitation for all sulfonamides was between 3 and 14 ppb. Recovery was evaluated for different meat matrixes. The mean recovery values were between 66.3% for pork meat samples and 71.5% for cattle meat samples.     

Quantitative Analysis of Sulfonamide Residues in Natural Animal Casings by HPLC

A multiresidue method has been developed for the simultaneous determination of sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethoxydiazine, sulfamethylthiazole, sulfamethazine, sulfamonomethoxine, sulfamethoxypyridazine, sulfisoxazole, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline in natural animal casings by HPLC after solid-phase extraction. The sulfonamides were extracted with acetonitrile and the extract cleaned up with an Oasis MCX SPE cartridge prior to analysis. Separation was on a ZOBAX Eclipse XDB-C₈ column using gradient elution with acetonitrile/methanol/0.1% acetic acid. The effect of separation conditions on chromatographic behavior and recovery has been studied. Calibration graphs were linear with very good correlation coefficients (r = 0.9983−0.9996) in the concentration range from 0.02 to 1 μg mL⁻¹. The limits of quantitation (LOQ) for the 13 sulfonamides were in the range of 1.5–2.2 μg kg⁻¹. Decision limits (CCα) and detection capabilities (CCβ) were in the range of 105.2–111.0 and 113.0–120.2 μg kg⁻¹, respectively. The recovery for casings spiked with 1.5–100 μg kg⁻¹ ranged from 65.2 to 85.9%. The relative standard deviations (RSDs) of the sulfonamides for six measurements at 100 μg kg⁻¹ were from 2.2 to 7.7%. The applicability of the method to the analysis of salted swine casings, salted sheep casings and dry casing samples was demonstrated.     

Determination of eight sulfonamides in bovine kidney by liquid chromatography/tandem mass spectrometry with on-line extraction and sample clean-up

A sensitive, high performance liquid chromatography/tandem mass spectrometric (i.e. mass spectrometry/mass spectrometry; LC/MS/MS) method with on-line extraction and sample clean-up for the screening and confirmation of residues of sulfonamides in kidney is described. The sulfonamides are extracted from homogenized kidney with methanol. After centrifugation of the extract, an aliquot of the extract is directly injected on the LC/MS/MS system with further extraction and clean-up of the sample on-line. Detection of the analytes was achieved by positive electrospray ionization (ESI) followed by multiple reaction monitoring. For each sulfonamide the collisional decomposition of the protonated molecule to a common, abundant fragment ion was monitored. The method has been validated for sulfadimethoxine, sulfaquinoxaline, sulfamethazine, sulfamerazine, sulfathiazole, sulfamethoxazole, sulfadiazine and sulfapyridine. Calibration curves resulting from spiked blank kidney samples at the 10-200 microg/kg level showed good linear correlation. At the level of 50, 100 and 200 microg/kg both within- and between-day precision, as measured by relative standard deviation (RSD), were less than 16%. The limits of detection (LODs) ranged from 5 to 13.5 microg/kg. The recoveries ranged from 78 to 82%. The procedure provides a rapid, reliable and sensitive method for the determination of residues of sulfonamides in bovine kidney. The advantage of this method over existing methods is its decreased sample preparation and analysis time, which makes the method more suitable for routine analysis.     

Simultaneous determination of 16 sulfonamides in honey by liquid chromatography/tandem mass spectrometry

A method is described for the determination of 16 sulfonamides in honey. Samples are dissolved in phosphoric acid solution (pH2), cleaned up with 2 solid-phase extraction (SPE) cartridges, an aromatic sulfonic cation-exchange cartridge and an Oasis HLB SPE cartridge, and analyzed both qualitatively and quantitatively by liquid chromatography/tandem mass spectrometry (LC/MS/MS) under the selected conditions. Without exception, calibration curves were linear (r = > 0.995), when sulfamethizole was between 1.0 and 25.0 microg/kg; sulfacetamide, sulfapyridine, sulfadiazine, sulfachloropyridazine, sulfamethoxazole, sulfamerazine, sulfisoxazole, sulfamonomethoxine, and sulfadoxine were between 2.0 and 50.0 microg/kg; sulfamethoxypyridazine, sulfadimethoxine, and sulfathiazole were between 4.0 and 100.0 microg/kg; sulfamethazine and sulfameter were between 8.0 and 200.0 microg/kg; and sulfaphenazole was between 12.0 and 300.0 microg/kg. Average recoveries at 4 fortification levels in the range of 1.0-300 microg/kg in honey were 70.9-102.5%, and relative standard deviations were 2.02-11.52%. The limits of quantitation for the 16 sulfonamides were between 1.0 and 12.0 microg/kg, with the LC/MS/MS method.     

Matrix solid-phase dispersion extraction and high-performance liquid chromatographic determination of residual sulfonamides in chicken.

Simultaneous determination of the six sulfonamides (SAs) sulfadiazine, sulfadimidine, sulfamonomethoxine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline in chicken using matrix solid-phase dispersion (MSPD) with neutral aluminium oxide as an MSPD sorbent and high-performance liquid chromatography (HPLC) is presented. In the present MSPD, six SAs could be isolated by only one step, elution with a 70% (v/v) aqueous ethanol solution, without the sorbent conditioning and the sorbent-tissue matrix washing. For the HPLC determination, a LiChrospher 100 RP-8 and a mixture of 1% acetic acid solution (pH 3.0, in water)-acetonitrile-N,N-dimethylformamide (78:22:5, v/v/v) as the mobile phase with a photodiode array detector were used. Average recoveries were greater than 87.6% with relative standard deviations between 0.5 and 8.6%. The total time and amount of solvent required for the analysis of one sample were <1.5 h and <12 ml, respectively.     

Solid phase extraction and HPLC determination of veterinary pharmaceuticals in wastewater

This work focuses on the application of SPE-HPLC analysis of important veterinary pharmaceuticals from different classes in highly complex wastewater matrix. The pharmaceutical investigated included three sulfonamides (sulfamethazine, sulfadiazine and sulfaguanidine), a sulfonamide synergist (trimethoprim), a tetracycline (oxytetracycline), a fluoroquinolone (enrofloxacine) and a β-lactame (penicillin G/procaine). The method involves pre-concentration and clean-up by solid phase extraction (SPE) using Oasis HLB extraction catridges. Final analysis of the selected pharmaceutical compounds was carried out by high-performance liquid chromatography (HPLC) coupled with diode array detector (DAD). Recoveries were ranged from 68.3 to 97.9% with relative standard deviation below 8.4%. Only for sulfaguanidine low recovery was obtained. Limits of quantification were in the range 1.5-100 μg/L depending on pharmaceutical. The described method was applied to the determination of pharmaceuticals in wastewater samples from pharmaceutical industry.     

毛细管电泳-电化学检测法测定饲料中的磺胺类药物

采用毛细管电泳-电化学检测法(CE-ED),对饲料中的6种磺胺类药物磺胺脒、磺胺二甲嘧啶、磺胺甲嘧啶、磺胺二甲氧嘧啶、磺胺嘧啶、磺胺甲恶唑进行了分离和测定。分别考察了工作电极电位、运行缓冲液的pH和浓度、分离电压和进样时间等实验参数对实验结果的影响。在优化的实验条件下,以直径300μm的碳圆盘电极为工作电极,检测电位为0.95 V(vs.SCE),在30 mmol/L硼砂-KH2PO4(pH7.6)的运行缓冲溶液中,6个分析物能够在16 min内实现很好的基线分离,被测物浓度与峰电流在3个数量级呈良好的线性,检出限(S/N=3)范围0.08～0.20μg/mL。该方法已应用于实际样品的分析。