QuEChERS/HPLC/DAD法同时检测果蔬中多种植物激素残留

采用高效液相色谱法,建立了同时分析玉米素(Z)、赤霉酸(GA)、多效唑(PBZ)、4-氟苯氧乙酸(4-FPA)、4-氯苯氧乙酸(4-CPA)、吲哚-3-乙酸(IAA)、吲哚-3-丁酸(IBA)、6-苄氨基嘌呤(6-BA)、脱落酸(ABA)、萘乙酸(NAA)、氯吡脲(CPPU)、2,4-二氯苯氧乙酸(2,4-D)及2,4,5-三氯苯氧乙酸(2,4,5-T)13种植物激素含量的方法。采用含0.5%甲酸的80%乙腈进行提取,分散固相萃取吸附剂(C18和硅藻土)进行净化,选取Waters XBridge C_(18)色谱柱,以乙腈-水为流动相进行梯度洗脱,二极管阵列检测器200~400nm检测,外标法定量。结果表明,13种植物激素在50 min内可实现基线分离,在线性范围内的相关系数(r)为0.992 1~0.999 3;加标回收率为68.4%~95.1%;相对标准偏差(RSD)均小于5%;方法的检出限为0.005~0.020 mg/kg;定量下限为0.01~0.09 mg/kg。该方法前处理操作快速、简便,具有良好的灵敏度、精密度和回收率,适用于果蔬的质量监控。     

Simultaneous analysis of different classes of phytohormones in coconut (Cocos nucifera L.) water using high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry after solid-phase extraction

Coconut (Cocos nucifera L.) water, which contains many uncharacterized phytohormones is extensively used as a growth promoting supplement in plant tissue culture. In this paper, a high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of various classes phytohormones, including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), abscisic acid (ABA), gibberellic acid (GA), zeatin (Z), N⁶-benzyladenine (BA), α-naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) in young coconut water (CW). The analysis was carried out using a reverse-phase HPLC gradient elution, with an aqueous mobile phase (containing 0.1% formic acid, pH adjusted to 3.2 with triethylamine (TEA)) modified by methanol, and solute detection made at 265 nm wavelength. The method was validated for specificity, quantification, accuracy and precision. After preconcentration of putative endogenous phytohormones in CW using C₁₈ solid-phase extraction (SPE) cartridges, the HPLC method was able to screen for putative endogenous phytohormones present in CW. Finally, the identities of the putative phytohormones present in CW were further confirmed using independent liquid chromatography–tandem mass spectrometry (LC–MS/MS) equipped with an electrospray ionization (ESI) interface.     

基于在线富集与原位衍生技术的植物组织中内源性油菜素甾醇的超高效液相色谱-串联质谱分析方法

油菜素甾醇是一类重要的植物激素,对植物的生长发育过程起显著调节作用。已报道的油菜素甾醇分析方法存在样品前处理过程复杂和灵敏度低等问题。本研究采用C18 PEEK管填充柱为富集柱,以4-N,N-二甲氨基苯硼酸为衍生试剂,搭建了基于双泵-双六通阀的在线管内固相微萃取-超高效液相色谱-串联质谱（UPLC-MS/MS）联用系统,对油菜素甾醇进行在线富集和原位衍生,实现植物组织中内源性油菜素甾醇的自动化分析。该系统程序化地控制了油菜素甾醇的进样、萃取、衍生、分离和检测过程,有效简化前处理过程,节省人力;在线富集步骤实现了样品溶液大体积进样,提高样品利用率;原位衍生改善了油菜素甾醇电喷雾的离子化效率,使油菜素甾醇的电喷雾质谱检出限降低至pg/mL。该系统可在300 mg鲜重植物组织中检测到内源性油菜素甾醇,已成功用于水稻、油菜中多种油菜素甾醇的定量分析。     

固相萃取-衍生化-气相色谱法测定血液中的3种苯氧羧酸类除草剂

建立了一种血液中2,4-二氯苯氧乙酸(2,4-D)、2-(2,4-二氯苯氧)-丙酸(2,4-DP)和4-氯-2-甲基-苯氧乙酸(MCPA)3种苯氧羧酸类除草剂的分析方法.血样用0.1 mol/L盐酸稀释后用GDX401大孔树脂吸附、用乙醚洗脱,萃取物用二氯丙醇在硫酸催化下进行酯化衍生,衍生物经气相色谱-电子捕获检测.2,4-D、2,4-DP和MCPA的检测限分别为20,8和40 ng/mL.定量分析用2,4-二氯苯乙酸作内标,线性关系和回收率结果均令人满意.     

Microwave-assisted extraction followed by gas chromatography-mass spectrometry for the determination of endocrine disrupting chemicals in river sediments

A method for the simultaneous measurement of trace amounts of phenolic xenoestrogens, such as 2,4-dichlorophenol (2,4-DCP), 4-tert-butyl-phenol (BP), 4-tert-octylphenol (OP), 4-nonylphenol (NP), pentachlorophenol (PCP) and bisphenol A (BPA), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS) analysis. The conditions for derivatization with acetic acid anhydride were investigated. A polydimethylsiloxane (PDMS)-coated stir bar and derivatization reagents were added to 10 ml of water sample and stirring was commenced for 10-180 min at room temperature (25 degrees C) in a headspace vial. Then, the extract was analyzed by TD-GC-MS. The optimum time for SBSE with in situ derivatization was 90 min. The detection limits of 2,4-DCP, BP, OP, NP, PCP and BPA were 2, 1, 0.5, 5, 2 and 2 pg ml(-1), respectively. The method showed good linearity over the concentration ranges of 10, 5, 2, 20, 10 and 10-1000 pg ml(-1) for 2,4-DCP, BP, OP, NP, PCP and BPA, respectively, and the correlation coefficients were higher than 0.99. The average recoveries of those compounds in river water samples were equal to or higher than 93.9% (R.S.D. <7.2%) with correction using the added surrogate standards. This simple, accurate, sensitive and selective method can be used in the determination of trace amounts of phenolic xenoestrogens in river water samples.     

Analytical method for the simultaneous determination of polyfunctional amines used as monomers in the manufacture of food packaging materials

This paper describes the development of a multi-analyte method for the determination of polyfunctional amines commonly used as monomers in the manufacture of food contact materials. Amines were analyzed by high-performance-liquid chromatography with diode-array detection (HPLC-DAD) after derivatization with dansyl chloride. The chromatographic analysis and the derivatization conditions were optimized. The proposed method was validated in terms of linearity, limits of detection and repeatabilities. The method showed an excellent sensitivity (LOD≤0.05 μg/mL) and appropriate repeatabilites (RSD (n=7)≤5%)). LC-MS/MS was used as a confirmatory technique. The stability of the amines in five food simulants (distilled water, 3% acetic acid, 10% ethanol, 50% ethanol and olive oil) under the most common testing conditions (10 days at 40 °C) was also studied. Results showed that amines had an acceptable stability in aqueous simulants but in the olive oil a loss of 100% was observed for all analytes.     

Optimized derivatization of acidic herbicides with trimethylsilyldiazomethane for GC analysis

In the present study, the preparation of methyl esters of chlorophenoxy acids with trimethylsilyldiazomethane (TMSD) is reported. TMSD is a mild and safe alternative to the highly toxic, thermally labile, and explosive diazomethane. Due to the novelty of this method, the characteristics of the reaction were investigated and the derivatization procedure was screened for statistically significant factors. The parameters identified as influential are the amount of methanol as well as reaction time and temperature. A careful optimization by a complete factorial response surface design was carried out to generate optimal reaction conditions with respect to maximum recovery and reaction yield. Special emphasis has been given to an accurate validation of the derivatization procedure. LODs were determined between 4.1 and 8.1 ng/mL for the enriched sample and linearity was proofed for more than five orders of magnitude. The applicability of the method was demonstrated by the analyses of quality control material including sample preparation with SPE. Polar herbicides investigated in the study belong to acetic acid (2,4-D, MCPA, and 2,4,5-T), butanoic acid (MCPB), and propanoic acid (mecoprop). An efficient, fast, and high-throughput method for the determination of polar herbicides including the potential for automation is proposed.     

Screening method for phenoxy acid herbicides in ground water by high-performance liquid chromatography of 9-anthryldiazomethane derivatives and fluorescence detection

A high-performance liquid chromatographic (HPLC) method for phenoxy acid herbicides using precolumn derivatization with 9-anthryldiazomethane (ADAM) is presented. The phenoxy acid herbicides investigated were (2,4-dichlorophenoxy)acetic acid, (4-chloro-2-methylphenoxy)acetic acid, 2-(4-chloro-2-methylphenoxy)propionic acid and (4-chloro-2-methylphenoxy)butyric acid. These herbicides reacted with ADAM under mild conditions and were converted into the corresponding fluorescent derivatives. The ADAM derivatives were separated by reversed-phase HPLC and determined using a fluorescence detector. The detection limits were about 500 pg per injection. For the application of ADAM to the determination of these herbicides in ground waters, the recoveries were more than 93% and the average relative standard deviation was 6.0% at 0.5 microgram/l. The procedure is useful as a screening method for phenoxy acid herbicides in ground water samples.     

Simultaneous determination of 13 phytohormones in oilseed rape tissues by liquid chromatography-electrospray tandem mass spectrometry and the evaluation of the matrix effect

In the experiment, a high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry with selected reaction monitoring was used to simultaneously determine various classes of phytohormones, including indole-3-acetic acid, α-naphthaleneacetic acid, 2-chlorobenzoic acid, 4-chlorobenzoic acid, indole-3-butyric acid, gibberellic acid, 2,4-dichlorophenoxyacetic acid, 2-naphthoxyacetic acid, abscisic acid, 2,3,5-triiodobenzoic acid, uniconazole, paclobutrazol and 2,4-epibassinolide in rape tissues. The analyses were separated by an HPLC equipped with a reversed-phase column using a binary solvent system composed of methanol and water, both containing 0.1% of formic acid. The matrix effect was also considered and determined. The technology was applied to analyze rape tissues, including roots, stems, leaves, flowers, immature pods and rape seeds. The rape tissues were subjected to ultrasound-assisted extraction and purified by dispersive solid-phase extraction, and then transferred into the liquid chromatography system. The detection limit for each plant hormone was defined by the ratio of signal/background noise (S/N) of 3. The results showed perfect linearity (R(2) values of 0.9987-1.0000) and reproducibility of elution times (relative standard deviations, RSDs,<1%) and peak areas (RSDs,<7%) for all target compounds.     

Simultaneous determination of monoamine and amino acid neurotransmitters in rat endbrain tissues by pre-column derivatization with high-performance liquid chromatographic fluorescence detection and mass spectrometric identification

A sensitive and efficient method for simultaneous determination of glutamic acid (Glu), gamma-amino-butyric acid (GABA), dopamine (DA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in rat endbrains was developed by high-performance liquid chromatography (HPLC) with fluorescence detection and on-line mass spectrometric identification following derivatization with 1,2-benzo-3,4-dihydrocarbazole-9-ethyl chloroformate (BCEOC). Different parameters which influenced derivatization and separation were optimized. The complete separation of five neurotransmitter (NT) derivatives was performed on a reversed-phase Hypersil BDS-C(18) column with a gradient elution. The rapid structure identification of five neurotransmitter derivatives was carried out by on-line mass spectrometry with electrospray ionization (ESI) source in positive ion mode, and the BCEOC-labeled derivatives were characterized by easy-to-interpret mass spectra. Stability of derivatives, repeatability, precision and accuracy were evaluated and the results were excellent for efficient HPLC analysis. The quantitative linear range of five neurotransmitters were 2.441-2x10(4) nM, and limits of detection were in the range of 0.398-1.258 nM (S/N=3:1). The changes of their concentrations in endbrains of three rat groups were also studied using this HPLC fluorescence detection method. The results indicated that exhausting exercise could obviously influence the concentrations of neurotransmitters in rat endbrains. The established method exhibited excellent validity, high sensitivity and convenience, and provided a new technique for simultaneous analysis of monoamine and amino acid neurotransmitters in rat brain.     

Ultrasound‐assisted emulsification microextraction combined with injection‐port derivatization for the determination of some chlorophenoxyacetic acids in water samples

An efficient method based on ultrasound‐assisted emulsification microextraction followed by injection‐port derivatization GC analysis was developed to determine 2,4‐dichlorophenoxyacetic acid (2,4‐D) and 4‐chloro‐2‐methylphenoxyacetic acid (MCPA) in natural water samples. In this procedure, 12.5 μL of 1‐undecanol was injected slowly into a 12 mL home‐designed centrifuge glass vial containing an aqueous sample of the analytes located inside an ultrasonic water bath. The resulting emulsion was centrifuged, and 1 μL of the separated organic solvent together with 1 μL of the derivatization reagent were injected into a GC equipped with a flame ionization detector. Several factors that influence the derivatization and extraction were optimized. Under the optimal conditions, the LODs were 0.33 and 1.7 μg/L for MCPA and 2,4‐D, respectively. Preconcentration factors of 670 and 836 were obtained for MCPA and 2,4‐D, respectively. The precision of the proposed method was evaluated in terms of repeatability, which was <5.7% (n = 5). The applicability of the proposed method was evaluated by extraction and determination of chlorophenoxyacetic acids from some natural waters, which indicated that the matrices of natural waters have no significant effect on the extraction and derivatization efficiency of this method.     

Production of ginseng saponin and polysaccharide by cell cultures ofPanax notoginseng andPanax ginseng

The effects of various combinations of the two kinds of phytohormones, auxin and cytokinin, on cell growth and production of ginseng saponin and polysaccharide were investigated in suspension cultures ofPanax notoginseng. It was found that a high concentration of kinetin (KT) (7 mg/L) seriously inhibited cell growth, but that of benzyl adenine (BA) did not. Under 0.7 mg/L of cytokinin (i.e., KT and BA), 2,4-dichlorophenoxy acetic acid (2,4-D) at 0.2 mg/L was better for the cell cultures than that at 2 or 20 mg/L; and for both naphthalene acetic acid (NAA) and indole acetic acid (IAA), 20 mg/L was their best level for the cell cultures. The highest cell concentration of 11.9 g/L (by dry wt) was obtained with the combination of 0.2 mg/L of 2,4-D and 0.7 mg/L of BA. The highest saponin content of 13.9% was achieved under 2.0 mg/L IAA and 0.07 mg/L KT; its highest production, i.e., 1.13 g/L, was obtained at 0.2 mg/L of 2,4-D and 0.7 mg/L of KT. Under 20 mg/L NAA and 0.7 mg/L KT, the highest polysaccharide content and production were reached, i.e., 16.4% and 1.86 g/L, respectively. In this work, the effects of phytohormones onP. ginseng cell cultures were also studied. A high saponin production of 1.78 g/L was observed at 10 mg/L of indole butyric acid and 0.1 mg/L of BA, and the highest production of polysaccharide (1.95 g/L) was reached with the combination of 10 mg/L NAA and 0.1 mg/L KT.     

Determination of bile acids in pig liver, pig kidney and bovine liver by gas chromatography-chemical ionization tandem mass spectrometry with total ion chromatograms and extraction ion chromatograms

An effective method has been developed for quantitative determination of six bile acids including lithocholic acid (LCA), deoxycholic acid (DCA), chenodeoxycholic acid (CDCA), hydodeoxycholic acid (HDCA), cholic acid (CA) and ursodeoxycholic acid (UDCA) in biological tissues including pig liver, pig kidney and bovine liver by gas chromatography-chemical ionization/tandem mass spectrometry (GC-CI/MS/MS). Camphor-10-sulphonic acid (CSA) was proposed as effective catalyst for bile acid derivatization. Reactions were accelerated ultrasonically. The effects of different catalysts and reaction times on derivatization efficiency were evaluated and optimized. Bile acids were determined as methyl ester-trimethylsilyl ether and methyl ester-acetate derivatives. The efficiency of trimethylsilylation and acetylation was evaluated. Trimethylsilylation was done with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) as the trimethylsilyl donating reagent in a ultrasonic bath for 20 min. Acetylation was done in pyridine with acetic anhydride at 40-45°C for 4 h. The former reaction was faster than the latter. Thus, trimethylsilylation was employed for the quantitative analysis. Negligible interferences from sterols in biological matrices were observed when the biological samples were treated with solid phase extraction before GC-CI/MS/MS. The linearity, reproducibility, detection limit and recovery were evaluated under the optimized conditions. Satisfactory results were obtained when bile acid derivatives of LCA, CDCA, HDCA, and UDCA were determined with total ion chromatograms (TIC) while DCA and CA were determined with extracted ion chromatograms (EIC), respectively. The detection limits (S/N=3) for six bile acids in biological tissues were ranging from 0.40 to 1.6 ng/mL and the recoveries indicated that the proposed method was feasible for the determination of trace bile acids in the biological samples studied. The experimental results for the animal tissues purchased from five different markets were compared. Interestingly, all of the six bile acids were present in pig liver while only the dihydroxy bile acids, DCA, CDCA and HDCA were found in pig kidney. In addition to DCA and CDCA, trihydroxy bile acid, CA, are the major bile acids in bovine liver.     

Determination of multiple phytohormones in fruits by high‐performance liquid chromatography with fluorescence detection using dispersive liquid–liquid microextraction followed by precolumn fluorescent labeling

Plant hormone determination in food matrices has attracted more and more attention because of their potential risks to human health. However, analytical methods for the analysis of multiple plant hormones remain poorly investigated. In the present study, a convenient, selective, and ultrasensitive high‐performance liquid chromatography method for the simultaneous determination of multiple classes of plant hormones has been developed successfully using dispersive liquid–liquid microextraction followed by precolumn fluorescent labeling. Eight plant hormones in fruits including jasmonic acid, 12‐oxo‐phytodienoic acid, indole‐3‐acetic acid, 3‐indolybutyric acid, 3‐indolepropionic acid, gibberellin A₃, 1‐naphthylacetic acid, and 2‐naphthaleneacetic acid were analyzed by this method. The conditions employed for dispersive liquid–liquid microextraction were optimized systematically. The linearity for all plant hormones was found to be >0.9993 (R² values). This method offered low detection limits of 0.19–0.44 ng/mL (at a signal‐to‐noise ratio of 3), and method accuracies were in the range of 92.32–103.10%. The proposed method was applied to determine plant hormones in five kinds of food samples, and this method can achieve a short analysis time, low threshold levels of detection, and a high specificity for the analysis of targeted plant hormones present at trace level concentrations in complex matrices.     

Pre-column derivatization of sulfa drugs with fluorescamine and high-performance liquid chromatographic determination at their residual levels in meat and meat products.

A rapid, sensitive and selective high-performance liquid chromatographic method is described for simultaneous determination of eight sulfa drugs in meat and meat products using pre-column derivatization with fluorescamine. The drugs are sulfisomidine, sulfadiazine, sulfamerazine, sulfadimidine, sulfamonomethoxine, sulfamethoxazole, sulfadimethoxine and sulfaquinoxaline. The method includes blender extraction of 3-g samples with chloroform, partition with 3 M hydrochloric acid, derivatization with fluorescamine at pH 3.0 and subsequent high-performance liquid chromatographic analysis on a C18 column with fluorescence detection at an excitation wavelength of 405 nm and an emission wavelength of 495 nm. The drugs were separated with a mobile phase of acetonitrile-2% acetic acid (3:5) at 55 degrees C. The average recovery from samples fortified at 0.1 ng/g was 92.6% with a coefficient of variation of 6.2%. The detection limit was 0.01 ng/g for sulfaquinoxaline and 0.005 ng/g for the other seven drugs. The method was field-tested in a survey of 37 samples including beef (five), pork (seven), chicken (seven), ham (five), sausage (eight), bacon (two) and roast beef (three). Sulfadimidine was detected in one pork sample at the level of 0.295 ng/g and in ham at 0.178 ng/g.     

Determination of abscisic acid by capillary electrophoresis with laser-induced fluorescence detection

A novel method based on capillary electrophoresis coupled to laser-induced fluorescence detection (CE-LIF) was developed for the determination of abscisic acid (ABA), which is an essential phytohormone during plant growth and development. ABA was labeled with 8-aminopyrene-1,3,6-trisulfonate via reductive amination in presence of acetic acid and sodium cyanoborohydride. The derivatization yield was maximized by optimizing several derivatization parameters including derivatization reagent concentration, reaction temperature and time. The conjugate was separated and quantitated by CE-LIF. The linearity of ABA was determined in the range from 0.1 to 10 micromol l(-1) with a correlation of 0.9979. The derivatization limit of detection for ABA was found to be 56 fmol (corresponding to the concentration of 2.8 x 10(-8) mol l(-1)). The detection limit for ABA was 5.5 amol for an injection volume of 5 nl. As a preliminary application, the proposed method was successfully applied to determining trace amount of ABA in the crude extracts of tobacco without extra purification and enrichment procedure and showed a better selectivity and sensitivity than those conventional methods used in determination of ABA.     

Towards a Non-Biased Formaldehyde Quantification in Leather: New Derivatization Conditions before HPLC Analysis of 2,4-Dinitrophenylhydrazine Derivatives

In leathers, formaldehyde is currently analyzed according to EN ISO 17226-1 standard, by reversed phase liquid chromatography after off-line precolumn derivatization with 2,4 dinitrophenylhydrazine (DNPH) in strong acidic conditions. We first demonstrate that this standard is not adapted to leather retanned with resins likely to release formaldehyde by hydrolysis. Indeed, formaldehyde content may be largely overestimated due to concomitant resin hydrolysis (in harsh acidic conditions) that releases formaldehyde during the derivatization step and during the waiting time on autosampler before analysis. Therefore, we thoroughly studied the derivatization step in order to propose new derivatization conditions. Replacing orthophosphoric acid by less acidic buffer solutions is not enough to avoid hydrolysis. A derivatization without adding acid is realized by solubilizing DNPH in acetonitrile instead of orthophosphoric acid. These conditions lead to a complete derivatization of formaldehyde in 3 h at 50 °C (in a water bath) while avoiding the hydrolysis of co-extracted dicyandiamide and melamine resins. The as-obtained leather extracts are stable over time. Formaldehyde contents found with this method agree with the formaldehyde content measured immediately at the end of derivatization reaction in standard conditions or with formaldehyde content measured by a home-designed flow injection analysis with acetylacetone online derivatization and UV detection.     

Simultaneous dispersive liquid–liquid microextraction based on a low‐density solvent and derivatization followed by gas chromatography for the simultaneous determination of chloroanisoles and the precursor 2,4,6‐trichlorophenol in water samples

Chloroanisoles, particularly 2,4,6‐trichloroanisole, are commonly identified as major taste and odor compounds in water. In the present study, a simple and efficient method was established for the simultaneous determination of chloroanisoles and the precursor 2,4,6‐trichlorophenol in water by using low‐density‐solvent‐based simultaneous dispersive liquid–liquid microextraction and derivatization followed by gas chromatography with electron capture detection. 2,4‐Dichloroanisole, 2,6‐dichloroanisole, 2,4,6‐trichloroanisole, 2,3,4‐trichloroanisole, and 2,3,6‐trichloroanisole were the chloroanisoles evaluated. Several important parameters of the extraction‐derivatization procedures, including the types and volumes of extraction solvent and disperser solvent, concentrations of derivatization agent and base, salt addition, extraction‐derivatization time, and temperature were optimized. Under the optimized conditions (80 μL of isooctane as extraction solvent, 500 μL of methanol as disperser solvent, 60 μL of acetic anhydride as derivatization agent, 0.75% of Na₂CO₃ addition w/v, extraction‐derivatization temperature of 25°C, without salt addition), a good linearity of the calibration curve was observed by the square of correlation coefficients (R²) ranging from 0.9936 to 0.9992. Repeatability and reproducibility of the method were < 4.5% and <7.3%, respectively. Recovery rates ranged from 85.2 to 101.4%, and limits of detection ranged from 3.0 to 8.7 ng/L. The proposed method was applied successfully for the determination of chloroanisoles and 2,4,6‐trichlorophenol in water samples.     

Simultaneous analysis of ten phytohormones in Sargassum horneri by high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry

Phytohormones have attracted wide attention due to their important biological functions. However, their detection is still a challenge because of their complex composition, low abundance and diverse sources. In this study, a novel method of high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry was developed and validated for the simultaneous determination of ten phytohormones including indole‐3‐acetic acid, isopentenyladenine, isopentenyl adenosine, trans‐zeatin riboside, zeatin, strigolactones, abscisic acid, salicylic acid, gibberellin A3, and jasmonic acid in Sargassum horneri (S. horneri). The phytohormones were extracted from freeze‐dried S. horneri with methanol/water/methanoic acid (15:4:1, v/v/v) analyzed on a Hypersil Gold C₁₈ column and detected by electrospray ionization tandem triple quadrupole mass spectrometry in the multiple reaction monitoring mode. The experimental conditions for the extraction and analysis of phytohormones were optimized and validated in terms of reproducibility, linearity, sensitivity, recovery, accuracy, and stability. Distributions of the phytohormones in the stems, blades, and gas bladder of the S. horneri in drift, fixed, and semi‐fixed growing states were investigated for the first time. The observed contents of the phytohormones in S. horneri range from not detected to 5066.67 ng/g (fresh weight). Most phytohormones are distributed mainly in the stems of S. horneri in drift and semi‐fixed states.     

气相色谱-质谱法测定水体中5种典型有机紫外防晒剂

建立了水体中5种典型有机紫外防晒剂甲氧基肉桂酸乙基己酯（ethylhexyl methoxycinnamate,EHMC）、二苯酮-3（benzophenone-3,BP-3）、4-甲基苄亚基樟脑（4-methylbenzylidene camphor,4-MBC）、奥克立林（octocrylene,OC）和胡莫柳酯（homosalate,HMS）的气相色谱-质谱检测方法。对HMS、BP-3衍生化条件进行了系统的优化。以100 μL双（三甲基硅烷基）三氟乙酰胺（N,O-bis（trimethylsilyl） trifluoroacetamide,BSTFA）为衍生化试剂,在100 ℃下反应100 min。水样固相萃取选用Oasis HLB萃取柱（0.5 g）,洗脱溶剂为乙酸乙酯-二氯甲烷（1：1,v/v）,水样pH 3~5。该方法对5种化合物的检出限范围为0.5~1.2 ng/L,定量限范围为1.4~4.0 ng/L。最佳实验条件下,加标水样回收率为87.85%~102.34%,相对标准偏差（n=3）均小于5%。该方法成功地应用于昆明市第一污水厂进出口水样中目标物质的分析。