Photodegradation processes of the antiepileptic drug carbamazepine, relevant to estuarine waters

The photodegradation of carbamazepine was studied in artificial estuarine water, under conditions relevant to the Rh?ne delta. Chloride substantially enhances the photodegradation of carbamazepine, most likely because of the interaction between Fe(III) colloids and Cl- ions under irradiation, yielding Cl2*-. For a given compound, prerequisites for the described degradation enhancement by chloride to be significant are faster degradation via reaction with Cl2*- compared to charge-transfer processes on the surface of Fe(III) colloids and an important role of indirect phototransformation compared to direct photolysis. A major photodegradation intermediate of carbamazepine is acridine, formed by direct photolysis, while hydroxylated/ oxidized compounds are formed in the presence of *OH, and chloroderivative formation is observed in the presence of Fe(III) and chloride.     

Triplet-sensitized photodegradation of sulfa drugs containing six-membered heterocyclic groups: identification of an SO2 extrusion photoproduct

The aquatic photochemical behavior of a class of sulfa drugs containing six-membered heterocyclic substituents (sulfamethazine, sulfamerazine, sulfadiazine, sulfachloropyridazine, and sulfadimethoxine) was investigated. Photodegradation of the sulfa drugs in a natural water sample was significantly enhanced relative to the degradation in deionized water, with the exception of sulfadimethoxine. This indicated an indirect photochemical process that was identified through the use of quenchers to be attributable to interaction with triplet excited-state dissolved organic matter (3DOM). The direct photolysis rate constant and quantum yield for both the neutral and anionic species of each sulfa drug were calculated using matrix deconvolution methods. The quantum yield values range from 0.01 x 10(-3) for the neutral form of sulfadimethoxine to 5 x 10(-3) for the anionic form of sulfamethazine and are significantly lower than those observed in a previous study for sulfa drugs containing five-membered heterocyclic substituents, although the rate constants are of similar magnitude. The primary product formed in both direct and indirect photodegradation for all five compounds was identified as a sulfur dioxide extrusion product. The predicted environmental half-lives solely attributable to direct photolysis range from 8.6 h in midsummer at 30 degrees latitude in pH 7 surface water for sulfachloropyridazine to 420 h in midwinter at 45 degrees in pH 7 surface water for sulfadimethoxine. These half-lives, except for sulfadimethoxine, will be decreased by interaction with 3DOM.     

Photochemical fate of pharmaceuticals in the environment: cimetidine and ranitidine

The photochemical fates of the histamine H2-receptor antagonists cimetidine and ranitidine were studied. Each of the two environmentally relevant pharmaceuticals displayed high rates of reaction with both singlet oxygen (1O2, O2(1delta(g))) and hydroxyl radical (*OH), two transient oxidants formed in sunlit natural waters. For cimetidine, the bimolecular rate constant for reaction with *OH in water is 6.5 +/- 0.5 x 10(9) M(-1) s(-1). Over the pH range 4-10, cimetidine reacts with 1O2 with bimolecular rate constants ranging from 3.3 +/- 0.3 x 10(6) M(-1) s(-1) at low pH to 2.5 +/- 0.2 x 10(8) M(-1) s(-1) in alkaline solutions. The bimolecular rate constants for ranitidine reacting with 1O2 in water ranges from 1.6 +/- 0.2 x 10(7) M(-1) s(-1) at pH 6-6.4 +/- 0.2 x 10(7) M(-1) s(-1) at pH 10. Reaction of ranitidine hydrochloride with *OH proceeds with a rate constant of 1.5 +/- 0.2 x 10(10) M(-1) s(-1). Ranitidine was also degraded in direct photolysis experiments with a half-life of 35 min under noon summertime sunlight at 45 degrees latitude, while cimetidine was shown to be resistant to direct photolysis. The results of these experiments, combined with the expected steady-state near surface concentrations of 1O2 and *OH, indicate that photooxidation mediated by 1O2 is the likely degradation pathway for cimetidine in most natural waters, and photodegradation by direct photolysis is expected to be the major pathway for ranitidine, with some degradation caused by 1O2. These predictions were verified in studies using Mississippi River water. Model compounds were analyzed by laser flash photolysis experiments to assess which functionalities within ranitidine and cimetidine are most susceptible to singlet-oxygenation and direct photolysis. The heterocyclic moieties of the pharmaceuticals were clearly implicated as the sites of reaction with 1O2, as evidenced by the high relative rate constants of the furan and imidazole models. The nitroacetamidine portion of ranitidine has been shown to be the moiety active in direct photolysis.     

Role of dissolved organic matter, nitrate, and bicarbonate in the photolysis of aqueous fipronil

A multivariate kinetic model of aqueous fipronil photodegradation was developed as a function of dissolved organic matter (DOM), bicarbonate, and nitrate at concentrations that bracketthose commonly observed in natural waters (ca. 0-10 mg/L). Several pathways were available for fipronil photodegradation in this system, including direct photolysis and indirect photooxidation by species produced during the illumination of natural waters (e.g., 3NOM*, 1O2*, *OH, *CO3(1-), *OOR, *OOH, e(aq)-, O2(*-)). Product studies indicated thatfipronil was quantitatively converted to fipronil desulfinyl, a product that is associated with direct photolysis alone. DOM was the only variable that affected fipronil degradation; it decreased the rate of fipronil photodegradation primarily through competitive light absorption (i.e., attenuation) and the quenching of fipronil*. The addition of sodium chloride (30 percent per thousand) resulted in a more rapid rate (approximately 20%) of fipronil loss in comparison to equivalent experiments performed without sodium chloride, implying that fipronil may be more photolabile in marine environments.     

New processes in the environmental chemistry of nitrite: nitration of phenol upon nitrite photoinduced oxidation

The role of nitrite as an environmental factor has been widely recognized. Nitrite is a relevant source of *OH in the atmosphere, both in the gas phase via photolysis of gaseous HNO2 and in atmospheric hydrometeors by photolysis of NO2-. In aqueous systems, *OH production through nitrite photolysis can be negligible due to the competition for light absorption by dissolved Fe(III), colloidal iron oxides, and nitrate. These photoexcited oxidants interact with NO2- and HNO2 to form *NO2, either directly or via formation of *OH. As a consequence, nitrite and nitrous acid may act as *NO2 rather than *OH sources. The radical *NO2 is involved in the nitration of many aromatic compounds, of which phenol is a model in this work. Kinetic measurements using 2-propanol as *OH scavenger show that the direct production of *OH by aqueous Fe(III) species decreases as pH increases. At slightly acidic and neutral pH values, oxidation of nitrite occurs by direct electron transfer to photoexcited Fe(III)aq species or colloidal iron oxides, in addition to the *OH-mediated oxidation of NO2-. The reported findings suggest a completely new role of nitrite in aquatic environments.     

Photochemical fate of sulfa drugs in the aquatic environment: sulfa drugs containing five-membered heterocyclic groups

The photochemical fate of five sulfa drugs with varying five-membered heterocyclic substituents (sulfamethoxazole, sulfisoxazole, sulfamethizole, sulfathiazole, and sulfamoxole) was investigated in aqueous solution. The rate of direct photolysis of these compounds is dependent upon the identity of the heterocyclic R group as well as the pH of the solution. Matrix deconvolution methods were employed to determine the absorption spectrum and photolysis rate of each protonation state (cationic, neutral, and anionic). From these data, quantum yields for direct photodegradation were calculated for each protonation state of the sulfa drugs. The quantum yields calculated range from <0.005 for the neutral state of sulfamethizole to 0.7 +/- 0.3 for the protonated state of sulfisoxazole. The protonation state that is most photoreactive varies among the sulfa drugs and cannot be attributed to the rate of photon absorption. Products arising from the direct photolysis of the sulfa drugs were also investigated. For all the compounds, sulfanilic acid was observed as a common product. The singlet oxygen quenching rates of the sulfa drugs were determined by laser flash photolysis and range from (2 +/- 1) x 10(4) M(-1) s(-1) for sulfamethoxazole to (3.0 +/- 0.7) x 10(8) M(-1) s(-1) for sulfamoxole. Reaction of the sulfa drugs with hydroxyl radical is not modulated by the R group, and the rate constants are all near the bimolecular diffusion-controlled limit of 10(10) M(-1) s(-1). The photodegradation of the sulfa drugs in natural water samples of Lake Josephine (St. Paul, MN) and Lake Superior was attributed solely to direct photolysis. This study indicates thatthese similarly structured antibiotics will be subject to a wide range of photodegradation rates with sulfathiazole degrading relatively quickly, sulfisoxazole and sulfamethizole degrading moderately, and sulfamethoxazole degrading much more slowly.     

Modeled direct photolytic decomposition of polybrominated diphenyl ethers in the Baltic Sea and the Atlantic Ocean

In this study, tetra- (#47), penta- (#99), and decabrominated (#209) diphenyl ethers were exposed (in isooctane) to summer sunlight at 60 degrees N, where their photochemical half-lives ranged from 0.6 to 203 h. Apparent quantum yields, ranging from 0.16 to 0.28, were applied to optical models to calculate the rates of direct photochemical decomposition at the surface (depth of 0 m) and in the mixing layer of the ocean. The calculated photolytic half-lives were 4-100 times as long in the mixing layer of the Baltic Sea and the North Atlantic Ocean as atthe surface of 0 m. Calculation of seasonal photochemical half-lives for the mixing layer of the North Atlantic Ocean from 0 degrees N to 60 degrees N showed that the solar photolysis effectively decomposes the congeners in the tropics. At mid- and high latitudes, where solar irradiances are lower outside summer, the photolysis rates for congeners #47 and #99 were often too low for their effective decomposition in the mixing layer. Although solar radiation can potentially decompose the congeners in the mixing layer of the ocean effectively, seasonal and latitudal variation in solar irradiance as well as optical and mixing properties of the ocean can make the direct photolytic decomposition ineffective at high latitude and the coastal ocean.     

UV photolysis of trichloroethylene: product study and kinetic modeling

Direct UV photolysis of trichloroethylene (TCE) in dilute aqueous solution generated chloride ions as a major end product and several reaction intermediates, such as formic acid, di- and monochloroacetic acids, glyoxylic acid, and, to a lesser extent, mono- and dichloroacetylene, formaldehyde, dichloroacetaldehyde, and oxalic acid. Under prolonged irradiation, these byproducts underwent photolysis, and a high degree of mineralization (approximately 95%) was achieved. TCE decays through the following major pathways: (1) TCE + h nu --> ClCH=C*Cl + Cl*; (2) TCE (H2O) + h nu --> ClCH(OH)-CHCl2; (3) TCE + h nu --> HC[triple bond]CCl + Cl2; (4) TCE + h nu --> ClC[triple bond]CCl + HCl; (5) TCE + Cl* --> Cl2HC-C*Cl2. A kinetic model was developed to simulate the destruction of TCE and the formation and fate of byproducts in aqueous solution under irradiation with polychromatic light. By fitting the experimental data, the quantum yields for the four photolysis steps were predicted as phi(1) = 0.13, phi(2) = 0.1, phi(3) = 0.032, and phi(4) = 0.092, respectively. The reaction mechanism proposed for the photodegradation of TCE accounts for all intermediates that were detected. The agreement between the computed and experimental patterns of TCE and reaction products is satisfactory given the complexity of the reaction mechanism and the lack of photolytic kinetic parameters that are provided in the literature.     

Depletion of four nitrofuran antibiotics and their tissue-bound metabolites in porcine tissues and determination using LC-MS/MS and HPLC-UV

Depletion of the nitrofuran antibiotics furazolidone, furaltadone, nitrofurantoin and nitrofurazone and their tissue-bound metabolites AOZ, AMOZ, AHD and SEM from pig muscle, liver and kidney tissues is described. Groups of pigs were given feed medicated with one of the nitrofuran drugs at a therapeutic concentration (400 mg kg^-1) for ten days. Animals were slaughtered at intervals and tissue samples collected for analysis for six weeks following withdrawal of medicated feed. These samples were analysed both for parent nitrofurans (using LC-MS/MS and HPLC-UV), and for tissue-bound metabolites (using LC-MS/MS). The parent drugs were detectable only sporadically and only in pigs subjected to no withdrawal period whatsoever. This confirms the instability of the four major nitrofuran antibiotics in edible tissues. In contrast, the metabolites accumulated to high concentrations in tissues (ppm levels) and had depletion half lives of between 5.5 and 15.5 days. The metabolites of all four drugs were still readily detectable in tissues six weeks after cessation of treatment. This emphasizes the benefits of monitoring for the stable metabolites of the nitrofurans.     

肉制品中硝基呋喃类药物残留的研究进展

硝基呋喃类药物是一类广谱性抗生素,在食用性动物疾病的预防与控制中具有广泛的应用。由于其可能具有基因诱变性,目前很多国家和地区已禁止使用这类药物,并规定在动物源性食品中硝基呋喃类残留物的检出限为不得检出。近年来,肉制品中硝基呋喃类药物及其代谢物残留的检测技术也得到迅速发展。本文综述硝基呋喃药物及其代谢物的特性和检测技术的...     

Kinetics and degradation products for direct photolysis of beta-blockers in water

Related to improving persistence assessment of active pharmaceutical ingredients (APIs), direct aqueous photolysis of beta-blockers: propranolol (hydrochloride salt), atenolol, and metoprolol (succinate salt) were investigated by exposing the samples (0.0003-10 mg L(-1)) to a solar irradiator (filtered xenon lamp: 290-800 nm) at 20-26 degrees C. Results suggested that direct photolysis in optically dilute solutions followed pseudo first-order kinetics. The measured half-lives of propranolol, atenolol, and metoprolol were approximately 16, 350, and 630 h, respectively. These were 3-5 orders of magnitude slower than the estimated minimum half-lives. The measured half-lives were related to day light surface conditions by comparing the light intensity of the lamp and the sun at different latitudes and seasons. Major direct photolysis products were identified from propranolol that led to a proposed reaction pathway, involving ring oxidation, rearrangement, and deoxygenation. Electron paramagnetic resonance (EPR) spectroscopy results confirmed that at least one carbon-based radical intermediate was formed during the direct photolysis of propranolol in aqueous solutions. The overall results demonstrated that with fast direct photolysis half-lives, propranolol is unlikely to be persistent in natural waters. Further work is needed to investigate indirect photolysis of atenolol and metoprolol in surface waters in order to understand the overall persistence of these APIs in the environment.     

Aqueous photochemical reaction kinetics and transformations of fluoxetine

Fluoxetine (FLX) was shown to be photoreactive in sunlit surface waters. FLX degraded in deionized water when exposed to simulated sunlight with a half-life of 55.2+/-3.6 h(-1). Photodegradation products were identified using high performance liquid chromatography-UV (HPLC-UV) and liquid chromatography tandem mass spectrometry (LC-MS-MS) using electrospray (ES) ionization. Defluorination of the trifluoromethyl group in FLX and in fluometuron and flutalanil,two other compounds containing this functional group, is suggested to be a common direct photolysis pathway for trifluoromethylated compounds. Products resulting from O-dealkylation of FLX were also observed. The rate of degradation was faster in synthetic field water where .OH was the likely dominant oxidant in the system. The bimolecular rate constant for the reaction between FLX and .OH was measured as (8.4+/-0.5) x 10(9) and (9.6 +/-0.8) x 10(9) M(-1) s(-1) using two different methods of competition kinetics. Indirect photodegradation reactions could lead to the production of hydroxylated and O-dealkylated compounds. Although direct photolysis could potentially limitthe persistence of FLX in surface waters, its degradation by indirect photolysis would proceed faster. Thus, this latter process could be important in the elimination of FLX in surface waters.     

Photodegradation of antibiotics on soil surfaces: laboratory studies on sulfadiazine in an ozone-controlled environment

Among the processes affecting transport and degradation of antibiotics released to the environment during application of manure and slurry to agricultural land, photochemical transformations are of particular interest. Drying-out of the top soil layer under field conditions enables sorption of surface-applied antibiotics to soil dust, thus facilitating direct, indirect, and sensitized photodegradation at the soil/atmosphere interface. For studying various photochemical transformation processes of sulfadiazine, a photovolatility chamber designed in accordance with the requirements of the USEPA Guideline and 161-3 was used. Application of 14C-labeled sulfadiazine enabled complete mass balances and allowed for investigating the impact of various surfaces (glass and soil dust) and environmental factors, i.e., irradiation and atmospheric ozone, on photodegradation and volatilization. Volatilization was shown to be a negligible process. Even after increasing the air temperature up to 35 degrees C only minor amounts of sulfadiazine and transformation products (0.01-0.28% of applied radioactivity) volatilized. Due to direct and indirect photodegradation, the highest extent of mineralization to 14CO2 (3.9%), the formation of degradation products and of nonextractable soil residues was measured in irradiated soil dust experiments using ozone concentrations of 200 ppb. However, even in the dark significant mineralization was observed when ozone was present, indicating ozone-controlled transformation of sulfadiazine to occur at the soil surface.     

Photochemical fate of carbamazepine in surface freshwaters: laboratory measures and modeling

It is shown here that carbamazepine (CBZ) would undergo direct photolysis and reaction with (?)OH as the main phototransformation pathways in surface waters. Environmental lifetimes are expected to vary from a few weeks to several months, and predictions are in good agreement with available field data. Acridine (I) and 10,11-dihydro-10,11-trans-dihydroxy-CBZ (V) are the main quantified phototransformation intermediates upon direct photolysis and (?)OH reaction, respectively. The photochemical yield of mutagenic I from CBZ is in the 3-3.5% range, and it is similar for both direct photolysis and (?)OH reaction: it would undergo limited variation with environmental conditions. In contrast, the yield of V would vary in the 4-8.5% range depending on the conditions, because V is formed from CBZ by (?)OH (9.0% yield) more effectively than upon direct photolysis (1.4% yield). Other important photointermediates, mostly formed from CBZ upon (?)OH reaction, are an aromatic-ring-dihydroxylated CBZ (VI) and N,N-bis(2-carboxyphenyl)urea (VII). Compounds VI and VII are formed by photochemistry and are not reported as human metabolites; thus, they could be used as tracers of CBZ phototransformation in surface waters. Interestingly, VI has recently been detected in river water.     

Aquatic photochemistry of isoflavone phytoestrogens: degradation kinetics and pathways

Isoflavones are plant-derived chemicals that are potential endocrine disruptors. Although some recent studies have detected isoflavones in natural waters, little is known about their aquatic fates. The photochemical behaviors of the isoflavones daidzein, formononetin, biochanin A, genistein, and equol were studied under simulated solar light and natural sunlight. All of these phytoestrogens were found to be photolabile under certain conditions. Daidzein and formononetin degraded primarily by direct photolysis. Their expected near-surface summer half-lives in pH 7 water at 47° latitude are expected to be 10 and 4.6 h, respectively. Biochanin A, genistein, and equol degraded relatively slowly by direct photolysis at environmentally realistic pH values, though they showed significant degradation rate enhancements in the presence of natural organic matter (NOM). The indirect photolysis rates for these compounds scaled with NOM concentration, and NOM from microbial origin was found to be a more potent photosensitizer than NOM from terrestrial sources. Mechanistic studies were performed to determine the indirect photolysis pathways responsible for the rate enhancements. Results of these studies implicate reaction with both singlet oxygen and excited state triplet NOM. Environmental half-lives for biochanin A, genistein, and equol are expected to vary on the basis of pH as well as NOM source and concentration.     

食品中硝基呋喃类药物及其代谢物残留检测的 研究进展

硝基呋喃类药物是一类人工合成的广谱抗菌药物,主要包括呋喃唑酮、呋喃妥因、呋喃它酮、呋喃西林等。因其价格相对低廉,曾大量应用于家禽、家畜和水产品动物的细菌性疾病的预防和治疗。原药在动物体内代谢速度快,半衰期短,其代谢物与蛋白组织结合紧密,残留时间长。研究发现原药及代谢物对人体有潜在的致癌致畸等作用,世界各国在动物源性食品生产过程中已全面禁止此类药物的使用,并规定了检测标准,但动物养殖者们违法使用硝基呋喃类药物的现象仍有发生。硝基呋喃类药物的检测方法繁多,主要有色谱分析法、免疫学方法等,各类方法均有其优点与局限性。本文综述了近年来对食品中硝基呋喃类药物及代谢物的残留检测方法,并对硝基呋喃类代谢物残留的检测方法的趋势进行展望。     

Photochemical oxidation of As(III) in ferrioxalate solutions

Photochemical reactions involving aqueous Fe(III) complexes are known to generate free radical species such as OH* that are capable of oxidizing numerous inorganic and organic compounds. Recent work has shown that As(III) can be oxidized to As(V) via photochemical reactions in ferric-citrate solutions; however, the mechanisms of As(III) oxidation and the potential importance of photochemical oxidation in natural waters are poorly understood. Consequently, the objectives of this study were to evaluate oxidation rates of As(III) in irradiated ferrioxalate solutions as a function of pH, identify mechanisms of photochemical As(III) oxidation, and evaluate the oxidation of As(III) in a representative natural water containing dissolved organic C (DOC). The oxidation of As(III) was studied in irradiated ferrioxalate solutions as a function of pH (3-7), As(III), Fe(III), and 2-propanol concentration. Rates of As(III) oxidation (0.5-254 microM h(-1)) were first-order in As(III) and Fe(III) concentration and increased with decreasing pH. Experiments conducted at pH 5.0 using 2-propanol as an OH* scavenger in light and dark reactions suggested that OH* is the important free radical responsible for As(III) oxidation. Significant rates of As(III) oxidation (4-6 microM h(-1)) were also observed in a natural water sample containing DOC, indicating that photochemical oxidation of As(III) may contribute to arsenic (As) cycling in natural waters.     

Reactions of hydroxyl radical with humic substances: bleaching, mineralization, and production of bioavailable carbon substrates

In this study, we examine the role of the hydroxyl (OH*) radical as a mechanism for the photodecomposition of chromophoric dissolved organic matter (CDOM) in sunlit surface waters. Using gamma-radiolysis of water, OH* was generated in solutions of standard humic substances in quantities comparable to those produced on time scales of days in sunlit surface waters. The second-order rate coefficients of OH* reaction with Suwannee River fulvic (SRFA; 2.7 x 10(4) s(-1) (mg of C/L)(-1)) and humic acids (SRHA; 1.9 x 10(4) s(-1) (mg of C/L)(-1)) are comparable to those observed for DOM in natural water samples and DOM isolates from other sources but decrease slightly with increasing OH* doses. OH* reactions with humic substances produced dissolved inorganic carbon (DIC) with a high efficiency of approximately 0.3 mol of CO2/mol of OH*. This efficiency stayed approximately constant from early phases of oxidation until complete mineralization of the DOM. Production rates of low molecular weight (LMW) acids including acetic, formic, malonic, and oxalic acids by reaction of SRFA and SRHA with OH* were measured using HPLC. Ratios of production rates of these acids to rates of DIC production for SRHA and for SRFA were similar to those observed upon photolysis of natural water samples. Bioassays indicated that OH* reactions with humic substances do not result in measurable formation of bioavailable carbon substrates other than the LMW acids. Bleaching of humic chromophores by OH* was relatively slow. Our results indicate that OH* reactions with humic substances are not likely to contribute significantly to observed rates of DOM photomineralization and LMW acid production in sunlit waters. They are also not likely to be a significant mechanism of photobleaching except in waters with very high OH* photoformation rates.     

Indirect photolysis promoted by natural and engineered wetland water constituents: processes leading to alachlor degradation

Wetland surface waters that received drainage from agricultural fields were probed for constituents that would promote the photodegradation of agriculture herbicides. Alachlor proved to be a good chemical probe for examining indirect photolysis due to its lack of reactivity by either direct photolysis or dark reaction pathways and its ubiquity as an agricultural herbicide. Water samples were taken from natural (Old Woman Creek) and engineered wetlands in Ohio that receive copious amounts of agricultural runoff. Possible photosensitizers including dissolved organic matter (DOM), iron, and nitrate were measured in the samples. In alkaline waters (pH > 7.8), the photochemical degradation of alachlor became important only in the presence of high nitrate levels (approximately equal to 1 mM). In pH-adjusted (approximately 4) samples, the observed degradation rate coefficient increased 3-18 times of that measured at the natural pH. Methanol quenching experiments and kinetics modeling suggest that hydroxyl radical is the principal reactant. The promotion of the reaction at the lower pH was apparently related to the activation of the photochemical pathways associated with the DOM and possibly iron-DOM complexes. The rate coefficients measured for the photodegradation of alachlor in reconstituted DOM isolates (cation-exchanged material with very low iron levels) were similar in magnitude to those measured in natural waters containing low amounts of nitrate and high amounts of DOM. Moreover, these reactions also exhibited a pH dependency. Thus, these results suggest that DOM plays a role in promoting an indirect photolytic mechanism that is highly pH dependent.     

超高效液相色谱法测定水体和沉积物中4 种硝基呋喃类抗生素

建立超高效液相色谱法同时测定水体和沉积物中的呋喃妥因、呋喃西林、呋喃它酮和呋喃唑酮4 种硝基呋喃类抗生素。水体样品过滤后直接用混合型阳离子交换（mixed-mode cation exchange,MCX）固相萃取柱富集净化;沉积物样品经乙腈-0.1%甲酸溶液（8∶2,V/V）提取,MCX固相萃取柱净化。采用BEH C18（100 mm×2.1 mm,1.7 μm）色谱柱分离,以0.1%甲酸溶液-乙腈为流动相梯度洗脱。4 种硝基呋喃类药物在10.0～200 μg/L质量浓度内范围线性关系良好,相关系数R2均大于0.999。水体和沉积物中的加标回收率分别为81.5%～103.2%和73.3%～91.9%,相对标准偏差分别为2.0%～5.8%和3.4%～9.6%（n=5）,检出限分别为0.03 μg/L和0.6 μg/kg,定量限分别为0.1 μg/L和2.0 μg/kg。该方法可应用于水体和沉积物中硝基呋喃类抗生素的残留检测。