Rapid simultaneous determination of 14 sulfonamides in wastewater by liquid chromatography tandem mass spectrometry

This paper describes a rapid method for the determination of 14 kinds of sulfonamides (SAs) in wastewater using SPE, and LC-MS/MS with positive ESI (ESI(+)) and selected reaction monitoring (SRM) mode. The SPE was performed on an Oasis hydrophilic-lipophilic-balanced (HLB) cartridge. Chromatographic separation on a C18 column was achieved using a binary eluent containing methanol and water with 0.2% formic acid. Typical recoveries of the analytes ranged from 22.3 to 87.0% at a fortification level of 100 ng/L. The LODs in wastewater except sulfathiazole (3 ng/L) could be detected and quantified at levels as low as 1 ng/L. Finally, the method was applied to water from the municipal outlet and the aquaculture wastewater effluent. Sulfamethazine (SM(2)), sulfamethoxypyridazine (SMP), and sulfamethoxazole (SMZ) were most frequently found in wastewater in a concentration range between 1.2 and 31.7 ng/L.     

固相萃取-液相色谱-串联质谱法同时测定水中14种短链和长链全氟化合物

建立了固相萃取-超高压液相色谱-三重四极杆质谱同时测定水中14种短链和长链全氟化合物（PFCs）的方法。水样经WAX混合型固相萃取小柱富集和净化后,采用BEH C18色谱柱、甲醇和5 mmol/L乙酸铵水溶液作为流动相进行梯度洗脱,质谱采用多反应监测模式,内标法定量分析。14种PFCs在0.1~50 μg/L范围内线性关系良好,相关系数大于0.99,方法检出限和定量限分别为0.09~1.15 ng/L和0.29~3.85 ng/L。在2、10和20 ng/L加标水平下,8种PFCs的平均回收率为85.0%、120.2%和117.4%,平均相对标准偏差为9.2%、9.0%和6.6%,6种PFCs的回收率相对较低,主要由于其在瓶/管壁上的吸附作用导致。应用本方法分析某淡水湖水样,检出4种短链和5种长链PFCs,质量浓度为41.29~49.05 ng/L和98.43~111.02 ng/L。结果表明该方法适用于对环境水体中短链和长链PFCs的同时分析测定。     

Liquid chromatography-tandem mass spectrometry to determine sedative hypnotic drugs in river water and wastewater

A method for simultaneous determination of four benzodiazepines (bromazepam (BMZ), carbamazepine (CBZ), diazepam (DZP) and nordiazepam (NDZ)) and four barbiturates (barbital (BTL), pentobarbital (PTB), phenobarbital (PNB) and secobarbital (SCB)) in river water and wastewater using solid-phase extraction (SPE) followed by liquid chromatography-(electrospray) tandem mass spectrometry (LC-(ESI)MS/MS) was developed. LC-(ESI)MS/MS analysis was performed in positive and negative modes for benzodiazepines and barbiturates, respectively, and in selected reaction monitoring (SRM). Limits of detection (LODs) were in the range of 0.2–5 ng/L for benzodiazepines and 2.5–50 ng/L for barbiturates. Precision (repeatability and reproducibility between days) expressed as %RSD (n = 5) was lower than 17% for low concentration (depending on the matrix between 50 and 250 ng/L for barbiturates, and between 5 and 25 ng/L for benzodiazepines), and lower than 15% for high concentration (between 200 and 1250 ng/L for barbiturates, and between 20 and 125 ng/L for benzodiazepines). Low matrix effect was observed for all compounds, except for BTL (75%) and PTB (–48%) in wastewater. The method was applied to water samples from two sewage treatment plants (STPs) and the rivers Ebre, Ter and Llobregat, located in Catalonia. CBZ was the target compound found at the highest concentration in river water (2.1–3.3 ng/L). In both influent and effluent wastewater samples, PNB, BMZ, CBZ, DZP and NDZ were determined at concentration levels ranging from 5.0 to 2337.3 ng/L.     

Development of a multi-residue method for the determination of organic micropollutants in water, sediment and mussels using gas chromatography-tandem mass spectrometry

This study describes the development of a multiresidue method based on gas chromatography-electron ionization-tandem mass spectrometry (GC-EI-MS/MS) for the detection of sixteen polycyclic aromatic hydrocarbons (PAHs), five phthalate esters (PEs), seven polychlorinated biphenyls (PCBs), six polybrominated diphenyl ethers (PBDEs), six alkylphenols (APs), three organochlorined pesticides and their isomers or degradation products (OCPs) and bisphenol A in seawater, river water, wastewater treatment plant (WWTP) effluents, sediments and mussels. Solid phase extraction (SPE) was used for the extraction of target analytes in aqueous samples, and ultrasound assisted extraction for solid samples. GC-EI-MS/MS acquisition conditions in selected reaction monitoring (SRM) using two transitions per compound were optimized. In this way, quantification and unequivocal identification of organic micropollutants were performed in compliance with the Decision 2002/657/EC. Good linearity responses with coefficients of determination higher than 0.99 were obtained. Methodological detection limits (MDLs) in seawater ranged from 0.1 to 6 ng L(-1); in river water from 0.1 to 4.8 ng L(-1); in WWTP effluents from 1 to 75 ng L(-1); in sediments from 1 to 150 ng g(-1) and in mussels from 1 to 125 ng g(-1). MDLs and recovery yields were compared with other published methods and similarities or even improvements were achieved. The optimized method was applied to analyze five samples from each matrix collected in coastal areas, showing its potential use for marine pollution monitoring.     

Determination of estrogenic steroids in surface water and wastewater by liquid chromatography-electrospray tandem mass spectrometry

An analytical method is presented which permits trace level determination of 17alpha-ethynylestradiol (EE2), 17beta-estradiol (E2), and estrone (E1). Using this method, the estrogenic steroids were analyzed in drinking water, surface water, and wastewater (sewage influents and effluents) at concentrations down to 0.1 ng/L. Sample volumes between 100 and 500 mL are concentrated using automated solid-phase extraction. Analysis is performed by liquid chromatography with detection by tandem mass spectrometry. Applying simple clean-up procedures and internal standard calibration, recovery losses resulting from matrix-dependent ion suppression during electrospray ionization could be compensated for all of the investigated compounds. Recoveries around 100% were obtained for all analytes after correction using the internal standards. Limits of quantification (LOQ) were between 0.1 and 0.4 ng/L for purified sewage, surface, ground, and drinking water and between 1 and 2 ng/L in the case of raw sewage. Water treatment by wastewater treatment plants (WWTPs) or by a surface water treatment plant affected the removal of all estrogenic steroids. Thus, E1, E2, and EE2 were removed in the municipal WWTPs to the extent of 93%, 93%, and 80%, respectively. In the effluents of the WWTP in Ruhleben (Berlin, Germany), E1, E2, and EE2 were detected at the low ng/L level. E2 and EE2 were, however, not present in the Berlin surface water above the LOQ (0.2 ng/L). E1 was the only compound that could be detected in surface water samples. After additional surface water treatment it was still detectable but only at trace-level concentrations with a mean value of 0.16 ng/L.     

C_(18)膜萃取/液相色谱-质谱联用法测定极地水体中有机磷酸酯

建立了C_(18)膜萃取/液相色谱-质谱联用技术测定极地水体中10种有机磷酸酯(OPEs)的方法。根据优化后的样品前处理及仪器方法,利用C_(18)膜富集4 L水体中的10种OPEs,经二氯甲烷超声提取,在电喷雾正离子模式下,采用选择反应监测(SRM)模式进行分析,线性相关系数为0.994 4~0.999 9。10种OPEs的加标回收率为64.1%~115%,方法检出限为0.08~0.55 ng/L。该方法适用于极地水体中10种OPEs的分析,利用该方法对北极水体样品中的10种OPEs进行检测,测得冰川融水中∑OPEs的质量浓度为0.64~6.64 ng/L,海水中∑OPEs的质量浓度为0.09~2.03 ng/L。     

Hydrophilic interaction liquid chromatography/tandem mass spectrometry for the analysis of diallyldimethylammonium chloride in water

We report a selective, sensitive and fast liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of diallyldimethylammonium chloride (DADMAC) in water. Hydrophilic interaction liquid chromatography (HILIC) was used to avoid ion-pairing reagents, which are generally employed to retain cationic compounds. The complementary information obtained in a triple quadrupole mass spectrometer and in an ion trap Orbitrap has been used to study the fragmentation of the DADMAC cation [M](+) and for the correct assignment of the products ions. The HILIC/MS/MS method developed, using electrospray ionization in positive ion mode and selected reaction monitoring (SRM) acquisition mode, led to a reliable determination and confirmation of the DADMAC cation in water samples down to 50 ng L(-1). The low detection limit achieved, in combination with the absence of matrix effects, allowed the direct analysis of samples without any pretreatment, preconcentration or clean-up step. DADMAC was determined in samples collected in a drinking water treatment plant (DWTP) in Barcelona (Spain) and it was found in the influent at the μg L(-1) level.     

固相萃取-气相色谱-质谱联用同时测定河水和海水中87种农药

采用固相萃取-气相色谱-质谱联用技术,建立了河水和海水中87种农药(24种有机磷、15种有机氯、12种唑类、9种拟除虫菊酯类、5种氨基甲酸酯类、7种酰胺类及15种其他新型农药)的多残留同时分析方法。优化了影响分离效果和灵敏度的仪器参数,考察了固相萃取柱柱型及水样体积、pH、盐度的影响,采用NH2柱优化了净化效果,内标法和替代物法用于数据的质量控制。结果表明: 在最佳条件下,各目标农药的方法检出限为0.1～6.6 ng/L;以实际河水和海水为基底,在5 ng/L和20 ng/L的加标水平下,绝大多数目标农药的回收率为60%～120%,相对标准偏差(n=4)为0.01%～9.7%。该法灵敏、准确,已成功地应用于福建九龙江河口区表层水样中多种类农药的复合污染监测,检出包括5种有机磷类、3种酰胺类、4种唑类、3种氨基甲酸酯类、2种拟除虫菊酯类等农药20种。     

Rapid liquid chromatography-tandem mass spectrometry method for the determination of a broad mixture of pharmaceuticals in surface water

Herein, a new method for the detection of 13 different pharmaceuticals and one metabolite in surface water at low ng/L levels is described. The method utilizes ultra performance liquid chromatography-tandem mass spectrometry and a solid-phase extraction sample preparation. Mean method detection limits were low (4.10 ng/L) and overall solid-phase extraction recovery and reproducibility was adequate (mean recovery, 77.9%; mean RSD, 7.3%). The method allows for quick run times and minimal solvent use as compared with other previously reported high performance liquid chromatography-based methods. Application of this method for the detection of pharmaceuticals in Tennessee River surface water determined that caffeine, sulfamethoxazole, and carbamazepine were frequently detected (100% of samples). Trimethoprim was moderately detected (30% of samples); acetaminophen, atorvastatin, and lovastatin were infrequently detected (10% of samples); and ciprofloxacin, diltiazem, fluoxetine, levofloxacin, norfluoxetine, ranitidine, and sertraline were not detected. This study reports the first detection of lovastatin in surface water.     

Simultaneous determination of benzophenone-type UV filters in water and soil by gas chromatography-mass spectrometry

A novel method has been developed to simultaneously determine and quantify seven organic UV filters employing liquid (solid)-liquid extraction, derivatization with N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) and gas chromatography with mass spectrometric detection in various environmental matrices. The UV filters determined were: benzophenone (BP), benzhydrol (BH), 4-hydroxybenzophenone (HBP), 2-hydroxy-4-methoxybenzophenone (HMB), 2,4-dihydroxybenzophenone (DHB), 2,2'-dihydroxy-4-methoxybenzophenone (DHMB) and 2,3,4-trihydroxylbenzophenone (THB). Under optimal conditions, the analysis required 23 min and good linearity over the range of 10-2,500 ng/L in water and 100-25,000 ng/kg in soil for each UV filter obtained. The high recovery (62-114% and 60-125% for water and soil samples, respectively) and the low RSD values (less than 13.9 and 17.2% for water and soil samples, respectively) indicated the high performance of this method. The method detection limits (MDLs) were relatively low, ranging from 5 to 100 ng/L or kg and quantification limits ranged between 25 and 500 ng/L or kg for all test compounds. This validated method was applied in the analysis of seven BP-type UV filters collecting water and soil samples in Korea, between April and May 2003. The overall concentration of UV filters in the soil sample (500-18,380 ng/kg) was highly distributed in water sample (27-204 ng/L). The established method was successfully applied to monitor the residue measurement of the BP-type UV filters in environmental water and soil samples.     

Book Reviews

A gas chromatography/ion trap mass spectrometry method was used for the trace analysis of atrazine and its deethylated degradation product deethylatrazine in environmental water and sediment samples. The isotope dilution technique was applied for the quantitative analysis of atrazine at parts-per-trillion levels. Water samples were pre-concentrated by solid-phase extraction using a C18 cartridge while the sediment samples were extracted by sonication with methanol. The concentrated extracts were analysed by a GC/ion trap MS operated in the MS/MS method. The extraction recoveries for the analytes were better than 83% when 1 L of water or 10 g of sediment was analysed. The method detection limits were 0.75 ng/L and 0.13 ng/g for atrazine and deethylatrazine detected in water and sediment, respectively. The precisions of the method represented by the relative standard deviation were in the range of 3.2-16.1%. The method was successfully applied to analyse surface water and sediment samples collected from Beijing Guanting reservoir. Trace levels of atrazine at 35.9-217.3 ng/L and 2.4-8.4 ng/g were detected in the water and sediment samples, respectively. The levels of deethylatrazine were five to 20 times lower that those of atrazine.     

Simultaneous analysis of 16 sulfonamide and trimethoprim antibiotics in environmental waters by liquid chromatography-electrospray tandem mass spectrometry

A sensitive liquid chromatography-electrospray tandem mass spectrometry method combined with solid-phase extraction and silica cartridge cleanup was established for 16 sulfonamides and trimethoprim in various water matrices. Signal suppression of all target analytes in sewage treatment plant influent, effluent and river water was improved by this method developed in this study. The method detection limits for 17 analytes were 20-200 pg/L for influent, 16-120 pg/L for effluent and 8.0-60 pg/L for river water with overall mean recoveries of 62-102% in all studied matrices. This method was used to analyze residual sulfonamides and trimethoprim in wastewater and river samples from Japan, and 8 analytes (0.08 (sulfadimethoxine)-161 ng/L (sulfapyridine) in wastewater and 10 (0.03 (sulfamethizol)-8.9 ng/L (sulfaquinoxaline) in river samples were detected.     

Validated dispersive liquid-liquid microextraction for analysis of organophosphorous pesticides in water

Dispersive liquid-liquid microextraction (DLLME) combined with gas chromatography and mass spectrometry (GC-MS) was applied to the determination of six organophosphorous pesticides (OPPs) in water samples. The analytes included in this study were prophos, diazinon, chlorpyrifos methyl, methyl parathion, fenchlorphos and chlorpyrifos. Several extraction and dispersion solvents were tested for dispersive liquid-liquid microextraction of these analytes and the best results were obtained using chloroform as extraction solvent and 2-propanol as dispersion solvent. Calibration curves of the analytes in water samples were constructed in the concentration range from 100 to 1100 ng/L for prophos, diazinon and methyl parathion and in the range from 100 to 1000 ng/L for chlorpyrifos methyl, fenchlorphos and chlorpyrifos. Limits of detection (LODs) were in the range of 1.5-9.1 ng/L and limits of quantification (LOQs) were in the range of 5.1-30.3 ng/L, below the maximum admissible level for drinking water. Relative standard deviations (RSDs) were between 6.5 and 10.1% in the concentration range of 100-1000 ng/L. The relative recoveries (%RRs) of tap, well and irrigation water samples fortified at 800 ng/L were in the range of 46.1-129.4%, with a larger matrix effect being detected in tap water.     

Comparison of electrospray ionization,atmospheric pressure chemical ionization and atmospheric pressure photoionization for determining estrogenic chemicals in water by liquid chromatography tandem mass spectrometry with chemical derivatizations

This study compared the sensitivities and matrix effects of four ionization modes and four reversed-phase liquid chromatographic (LC) systems on analyzing estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), 4-nonylphenol (NP), 4-tert-octylphenol (OP), bisphenol A (BPA) and their derivatives of dansyl chloride or pentafluorobenzyl bromide (PFBBr) in water matrixes using a triple-quadrupole mass spectrometer with selected reaction monitoring (SRM). The four probes were electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), atmospheric pressure photoionization (APPI) and APCI/APPI; the four LC systems were ultra-performance liquid chromatography (UPLC) with or without post-column split, a mixed-mode column and two-dimensional LC (2D-LC). Dansylated compounds with ESI at UPLC condition had the most intense signals and less matrix effects of the various combinations of ionization and LC systems. The on-column limits of detection (LODs) of dansylated estrogens by SRM were 0.05–0.20 pg, and the LODs in sewage treatment plant effluent and in river water were 0.23–0.52 and 0.56–0.91 ng/L, respectively. The LODs using selected ion monitoring (SIM) reached low ng/L levels in real samples and measured concentrations were comparable with those of SRM.     

两种微波等离子体炬质谱测定水中铅的对比研究

建立了一种新型的能够灵敏分析水中痕量铅的质谱方法,以微波等离子体炬(MPT)为离子源,可无需样品预处理而直接分析水样。样品经雾化和去溶后由MPT的中心管道引入等离子体,离子由国产的四极杆质谱仪(Q-MS)检测,得到铅的MPT特征质谱。定量结果表明,该方法的检出限为20 ng/L,线性范围为200~1 000 ng/L,相对标准偏差(RSD)为5.3%;所得定量指标优于相同条件下商用的线性离子阱质谱(LTQ-MS)测试结果,且四极杆质谱仪上所得的铅离子特征质谱信号更简单、易归属,无需复杂的多级串联质谱加以确认。这种MPT可与国产质谱仪器相结合发展成为一种低成本的现场检测铅的质谱仪器,在环境监控、饮用水检验等方面具有一定的应用价值。     

Determination of eight nitrosamines in water at the ng L(-1) levels by liquid chromatography coupled to atmospheric pressure chemical ionization tandem mass spectrometry

In this work, we have developed a sensitive method for detection and quantification of eight N-nitrosamines, N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMor), N-nitrosomethylethylamine (NMEA), N-nitrosopirrolidine (NPyr), N-nitrosodiethylamine (NDEA), N-nitrosopiperidine (NPip), N-nitroso-n-dipropylamine (NDPA) and N-nitrosodi-n-butylamine (NDBA) in drinking water. The method is based on liquid chromatography coupled to tandem mass spectrometry, using atmospheric pressure chemical ionization (APCI) in positive mode with a triple quadrupole analyzer (QqQ). The simultaneous acquisition of two MS/MS transitions in selected reaction monitoring mode (SRM) for each compound, together with the evaluation of their relative intensity, allowed the simultaneous quantification and reliable identification in water at ppt levels. Empirical formula of the product ions selected was confirmed by UHPLC-(Q)TOF MS accurate mass measurements from reference standards. Prior to LC-MS/MS QqQ analysis, a preconcentration step by off-line SPE using coconut charcoal EPA 521 cartridges (by passing 500 mL of water sample) was necessary to improve the sensitivity and to meet regulation requirements. For accurate quantification, two isotope labelled nitrosamines (NDMA-d(6) and NDPA-d(14)) were added as surrogate internal standards to the samples. The optimized method was validated at two concentration levels (10 and 100 ng L(-1)) in drinking water samples, obtaining satisfactory recoveries (between 90 and 120%) and precision (RSD<20%). Limits of detection were found to be in the range of 1-8 ng L(-1). The described methodology has been applied to different types of water samples: chlorinated from drinking water and wastewater treatment plants (DWTP and WWTP, respectively), wastewaters subjected to ozonation and tap waters.     

液相色谱-串联质谱法检测贝类产品中的原多甲藻酸贝类毒素

建立了一种贝类组织中原多甲藻酸(azaspiracid, AZA)贝类毒素主要成分AZA1的高效液相色谱-串联质谱检测方法。本方法采用甲醇-水(80:20, v/v)溶液对贝类组织中AZA1进行提取,并用MAX阴离子交换固相萃取(SPE)柱富集净化,使用Atlantis dC18(150 mm×4.6 mm, 5.0 μm)色谱柱分离,以含有50 mmol/L甲酸和2 mmol/L甲酸铵的乙腈-水溶液(80:20, v/v)为流动相进行等度洗脱,质谱采用选择反应监测(SRM)模式。AZA1在5 min内获得完全分离,且在48.85～2 442 ng/L范围内线性良好,相关系数为0.998 1。该方法检出限(S/N=3)为11.00 pg/g,添加水平为36.64、73.27、146.54 pg/g时的平均回收率为75.8%～82.5%(n=6),相对标准偏差小于10%。利用该方法对采自大连、青岛、广州水产品市场上的112个贝类样品进行了分析,发现采自大连和广州的部分贝类样品中含有AZA1。结果表明,该方法具有简单、快速、灵敏度高等特点,能充分满足贝类中AZA1检测的要求。     

Gas chromatography/ion trap mass spectrometry applied for the analysis of triazine herbicides in environmental waters by an isotope dilution technique

A gas chromatography/ion trap mass spectrometry method was developed for the analysis of simazine, atrazine, cyanazine, as well as the degradation products of atrazine, such as deethylatrazine and deisopropylatrazine in environmental water samples. Isotope dilution technique was applied for the quantitative analysis of atrazine in water at low ng/l levels. One liter of water sample spiked with stable isotope internal standard atrazine-d₅ was extracted with a C₁₈ solid-phase extraction cartridge. The analysis was performed on an ion trap mass spectrometer operated in MS/MS method. The extraction recoveries were in the range of 83-94% for the triazine herbicides in water at the concentrations of 24, 200, and 1000 ng/l, while poor recoveries were obtained for the degradation products of atrazine. The relative standard deviation (R.S.D.) were within the range of 3.2-16.1%. The detection limits of the method were between 0.75 and 12 ng/l when 1 l of water was analyzed. The method was successfully applied to analyze environmental water samples collected from a reservoir and a river in Hong Kong for atrazine detected at concentrations between 3.4 and 26 ng/l.     

Efficient approach for the reliable quantification and confirmation of antibiotics in water using on-line solid-phase extraction liquid chromatography/tandem mass spectrometry

The potential of solid-phase extraction coupled on-line to liquid chromatography/electrospray tandem mass spectrometry (SPE-LC-ESI-MS/MS) has been investigated in this paper for the efficient sensitive quantification and confirmation of 16 antibiotics in water. The list of targeted analytes included 10 quinolones (oxolinic acid (OXO), nalidixic acid (NAL), flumequine (FLU), marbofloxacine (MAR), ofloxacine (OFLO), enrofloxacine (ENR), pefloxacine (PEF), ciprofloxacine (CIP), pipemidic acid (PIPE), norfloxacine (NOR)) and 6 penicillins (penicillin G (PEN), oxacillin (OXA), dicloxacillin (DIC), piperacillin (PIP), cloxacillin (CLO) and ampicillin (AMP)) that were determined in ground and surface water. The procedure is based on the injection of 9.8 mL of sample into the SPE-LC-MS/MS system and the measurement of antibiotics by selected reaction monitoring mode, using a triple quadrupole analyser. The method has been validated at realistic low concentrations that might be present in environmental water, i.e. 10 and 100 ng L(-1), obtaining recoveries between 74% and 123% with relative standard deviation lower than 14%. Matrix effects were not relevant in most of cases, except for ampicillin in surface water, where notable signal suppression was observed. The limits of detection were as low as 0.4-4.3 ng L(-1). The method developed allows the rapid screening and quantification of all the analytes selected by acquiring one MS/MS transition (normally the most sensitive) for each compound. It was applied to a number of actual surface and groundwater samples with several compounds being detected, mainly quinolones, at low ng L(-1) levels. Special attention was given to the confirmation of compounds detected in water due to the difficulties of obtaining confident confirmation at low ng L(-1). This matter has been of growing concern in the last few years as reflected by recent papers and correspondence. The acquisition of several MS/MS transitions for each compound detected in a second independent analysis allowed the unequivocal confirmation of identity, avoiding reporting false-positives. Finally, the potential of QTOF instruments to confirm positive samples has also been evaluated and compared with triple quadrupole analysers.     

Derivatization of beta-dicarbonyl compound with 2,4-dinitrophenylhydrazine to enhance mass spectrometric detection: application in quantitative analysis of houttuynin in human plasma

Houttuynin (decanoyl acetaldehyde), a beta-dicarbonyl compound, is the major antibacterial constituent in the volatile oil of Houttuynina cordata Thunb. In the present work, detection of houttuynin in human plasma based on the chemical derivatization with 2,4-dinitrophenylhydrazine (DNPH) coupled with liquid chromatography/tandem mass spectrometry was described. The primary reaction products between the beta-dicarbonyl compound and DNPH in aqueous phase were identified as heterocyclic structures, of which the mass spectrometric ionization and fragmentation behavior were characterized with the aid of high-resolution multistage mass spectral analysis. For quantification, houttuynin and internal standard (IS, benzophenone) in plasma were firstly converted to their DNPH derivatives without sample purification, then extracted from human plasma with n-hexane and detected by liquid chromatography tandem mass spectrometry performed in selected reaction monitoring (SRM) mode. This method allowed for a lower limit of quantification (LLOQ) of 1.0 ng/ml using 100-microl plasma. The validation results showed high accuracy (%bias < 2.1) and precision (%CV < 7.2) at broad linear dynamic range (1.0-5000 ng/ml). The simple and quantitative derivatization coupled with tandem mass spectrometric analysis facilitates a sensitive and robust method for the determination of plasma houttuynin in pharmacokinetic studies.