气相色谱-负化学离子源质谱法检测胡萝卜中残留的环氟菌胺

建立了胡萝卜中环氟菌胺残留量的气相色谱-负化学离子源质谱(GC-NCI/MS)检测方法。用乙酸乙酯对胡萝卜中的环氟菌胺进行提取,并经固相萃取(SPE)净化后,由GC-NCI/MS在选择离子监测模式(SIM)下测定。该方法的准确度和精密度较高,在0.005,0.01,0.02,0.04 mg/kg 4个加标水平下,环氟菌胺的平均回收率均处于74.9%～96.4%之间,相对标准偏差(RSD)小于9.7%。在10～1000ng/mL范围内线性关系良好,检出限为0.001 mg/kg,定量限为0.005 mg/kg。该方法选择性好,抗干扰能力强,可作为胡萝卜中环氟菌胺残留检测的确证方法。     

Liquid chromatographic/electrospray ionization mass spectrometric studies of proanthocyanidins in foods

The proanthocyanidins in three foods (pinto beans, plums and cinnamon) were studied with electrospray ionization (ESI) mass spectrometry (MS) in the negative mode following separation by normal-phase high-performance liquid chromatography. The MS/MS analysis demonstrated that the major ions derived from heterocyclic ring fission and retro-Diels-Alder reaction of flavan-3-ol provided information about the hydroxylation pattern and type of interflavan bond. The connection sequence of the oligomers was identified through diagnostic ions derived from quinone methide (QM) cleavage of the interflavan bond. Novel heterogeneous B-type proanthocyanidins containing (epi)afzelechin as subunits were identified in pinto beans. Proanthocyanidins with interestingly different A-type linkages were identified in plums and cinnamon. In efforts aimed at extending the identification capacity of ESI-MS to polymers, we found that the polymeric procyanidins fragmented readily instead of forming multiply charged ions in the negative ESI mode. Fragmentation patterns were proposed based on our data obtained by ESI-MS/MS and ESI time-of-flight MS.     

气相色谱-串联质谱法测定台湾青枣中的炔螨特、戊唑醇和溴螨酯残留

建立了台湾青枣（Zizyphus mauritiana Lam）中炔螨特、戊唑醇和溴螨酯同时测定的气相色谱-串联质谱（GC-MS/MS）分析方法。样品用乙腈匀浆提取,盐析,石墨化炭黑/氨基混合型固相萃取柱净化,乙腈/甲苯（3：1,v/v）洗脱,浓缩定容后检测。目标化合物经SLB-5MS色谱柱（30 m×0.25 mm×0.25 μm）分离,采用三重串联四极杆质谱多反应监测（MRM）模式进行定性定量分析。结果表明,在0.01~0.50 mg/kg添加水平时,3种农药的回收率为75.8%~103.6%,相对标准偏差为1.7%~9.3%（n=5）。方法的线性范围为0.01~0.50 mg/kg,决定系数（R²）>0.99。该方法对炔螨特、戊唑醇和溴螨酯的定量限均为0.01 mg/kg,能满足台湾青枣中炔螨特、戊唑醇和溴螨酯残留检测的要求。     

Selective determination of caffeine and trigonelline in aqueous extract of green coffee beans by FT-MIR-ATR spectroscopy

A non-destructive, fast, simple and reliable Fourier transform mid-infrared attenuated total reflectance spectroscopy (FT-MIR-ATR) method for the selective determination of caffeine and trigonelline in the aqueous extract of green coffee beans was developed and validated. The calibration curves were linear in the range 2000 − 7000 mg/L for caffeine and trigonelline with R² ≥ 0.9997. The limits of detection (LOD) were 140 and 100 mg/L and the limits of quantification (LOQ) were 470 and 330 mg/L for caffeine and trigonelline, respectively. The precision (% RSD) was 3.0% and 4.3% for caffeine and trigonelline, respectively. The developed method was applied to 20 samples of green coffee beans to determine the two alkaloids. The amount of caffeine and trigonelline in the green coffee beans were found in the range 0.84 − 1.15% (w/w) and 0.83 − 1.13% (w/w), respectively. The accuracy of the developed analytical method was evaluated by spiking standard caffeine and trigonelline to green coffee beans and the average recoveries were 93 ± 5% and 98 ± 4%, respectively. Therefore, the developed FT-MIR-ATR methods can be used for direct determination of the two alkaloids in the green coffee beans.     

Sensitive and fast determination of Sudan dyes in chili powder by partial-filling micellar electrokinetic chromatography-tandem mass spectrometry

A fast and sensitive method for the simultaneous determination of Sudan dyes (I, II, III, and IV) in food samples was developed for the first time using partial filling micellar electrokinectic chromatography-mass spectrometry (MEKC-MS). The use of MEKC was essential to achieve the separation of these neutral analytes, while the partial filling technique was necessary to avoid the contamination of the ion source with non-volatile micelles. MEKC separation and MS detection conditions were optimized in order to achieve a fast, efficient, and sensitive separation of the four dyes. Filling 25% of the capillary with an MEKC solution containing 40 mM ammonium bicarbonate, 25 mM SDS, and 32.5% (v/v) acetonitrile, a baseline separation of the four azo-dyes was obtained in 10 min. Tandem MS was investigated in order to improve the sensitivity and selectivity of the analysis. Limits of detection (LOD) values 5, 8, 15, and 29 times better were obtained for Sudan III, I, II, and IV, respectively, using partial filling MEKC-MS/MS instead of partial filling MEKC-MS. Under optimized conditions, LOD from 0.05 to 0.2 μg/mL were obtained. The suitability of the developed method was demonstrated through the fast and sensitive determination of Sudan I, II, III, and IV in spiked chilli powder samples. This determination could not be achieved by MEKC-UV due to the existence of several interfering compounds from the matrix.     

Determination of three natural pesticides in processed fruit and vegetables using high-performance liquid chromatography/tandem mass spectrometry

This paper describes a method for the sensitive and selective determination of two macrocyclic lactones (abamectin and spinosad) and azadirachtin in apple purée, concentrated lemon juice, tomato purée and canned peas. The general sample extraction-partitioning method for our gas chromatography and liquid chromatography multiresidue methods has been used. The analytical procedure involves an extraction with acetone and liquid-liquid partitioning with ethyl acetate/cyclohexane combined in one step. The extracts are analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) without any further clean-up step. The pesticides are separated on a reversed-phase C12 column using a gradient elution. Thirteen simultaneous MS/MS transitions of precursor ions were monitored. Studies at fortification levels of 2.5-10 microg/kg and 25-100 microg/kg gave mean recoveries ranging from 70-100% for all compounds with satisfactory precision (relative standard deviation (RSD) from 3-20%). The excellent selectivity and sensitivity allows quantification and identification of low levels of pesticides in canned peas, tomato and apple purées (limits of quantitation (LOQs) 1-5 microg/kg) and in concentrated lemon juice (LOQs 2-10 microg/kg). The quantification of analytes was carried out using the most sensitive transition for every compound and by 'matrix-matched' standards calibration.     

Hypotensive effects on spontaneously hypertensive rats and antifungal activity on various species of Fusarium oxysporum of diethylstilbestrol-related compounds

The diethylstilbestrol-related compounds 3,3'-dihydroxy-alpha, beta-diethyldiphenylethane (I), diethylstilbestrol (II) and hexestrol (III) showed hypotensive effects on spontaneously hypertensive rats (SHR) and antifungal activities against all Fusarium oxysporum sp. tested. As previously reported, I had strong hypotensive action on normotensive rats at the dose of 10 mg/kg, while II and III showed weak hypotensive effects on these rats at the same dose. In this work, all three compounds also had hypotensive actions on SHR at the same dose. I showed the strongest hypotensive effect (-80.0 +/- 5.0 mmHg, 10 mg/kg, i.v.) on both SHR and normotensive rats. The three compounds also had antifungal activities against five kinds of Fusarium oxysporum sp. tested. Especially, II strongly inhibited the growth of Fusarium oxysporum f. sp. raphani IFO-9972 (minimum inhibitory concentration (MIC): 1.0 micrograms/ml).     

Determination of acidic herbicides in fruits and vegetables using liquid chromatography tandem mass spectrometry (LC-MS/MS)

The use of quick, easy, cheap, effective, rugged and safe method followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) was found to be the best combination for multiresidue determination of eight acidic herbicides in fruits and vegetables in terms of high recovery, short time of analysis, low cost and safety. Recent few articles were published for determination of different classes of acidic herbicides in single multiresidue method. In the present study, mass spectrophotometric conditions were individually optimised for eight acidic herbicides, namely 2,4-dichlorophenoxyacetic acid, bentazone, bromoxynil, fluazifop, fluroxypyr, imazethapyr, ioxynil and triclopyr to achieve maximum sensitivity and selectivity in multiple reaction monitoring (MRM) mode allowing simultaneous identification and quantification in a single run. Identity confirmation and quantitation were attained by using negative electrospray ionisation LC-MS/MS (ESI?) in MRM mode. Due to LC-MS/MS signal suppression, determination of pesticide residues was based on matrix-matched standard calculations. Most of the evaluated compounds showed a recovery ranging from 81% to 113% with relative standard deviations less than 16 % indicating acceptable precision. The precision and accuracy of the method were determined from recovery experiments on six replicates of spiked blank strawberry and green beans samples at 0.01, 0.05 and 0.1 mg/kg. The developed assay was linear over concentration range of 0.01–0.5 µg/mL, with correlation coefficient greater than 0.99 at the limit of quantitation 0.01 µg/mL. The proposed assay was successfully applied for the analysis of the studied acidic herbicides residues in two proficiency test samples. This wide scope assay protocol is applicable for monitoring acidic herbicides residues in fruits and vegetables by national regulatory authorities and accredited labs in order to help ensuring the safety of such widely used food products.     

高效液相色谱-串联质谱法测定芽苗类蔬菜及其来源豆类中4种非法添加物的残留量

建立了芽苗类蔬菜及其来源豆类中对氯苯氧乙酸、6-苄基腺嘌呤、恩诺沙星和诺氟沙星残留量的反相高效液相色谱-串联质谱(LC-MS/MS)检测方法。样品经含0.1%冰醋酸的乙腈提取、浓缩后,以C18为分析色谱柱,甲醇和0.1%甲酸水溶液作为流动相进行梯度洗脱分离。质谱采用电喷雾方式电离,正、负离子分段扫描,测定上述4种非法添加物。选择确定对氯苯氧乙酸、6-苄基腺嘌呤、恩诺沙星和诺氟沙星的母离子依次为m/z 189.9、226.1、359.9和320.1,定量子离子依次为m/z 127.0、91.2、315.9和276.2。4种药物在5～200 μg/L范围内线性关系良好(r2＞ 0.995)。选取了绿豆芽和绿豆作为代表性基质进行添加回收试验,4种药物的检出限和定量限分别为1 μg/kg和5 μg/kg;在5.0、10.0、20.0 μg/kg 3个添加水平下,4种药物的回收率为70%～91%,相对标准偏差(RSD)小于14%。方法准确、灵敏、简便,适用于芽苗类蔬菜及其来源豆类中4种非法添加物残留的同时测定。     

唐古特瑞香生物活性二萜的研究I.抗生育活性二营唐古特瑞香甲素的分离与结构

从中国特有瑞香科植物古特瑞香的乙醇提取物中分得一新的抗生育活性二萜,命名为唐古特瑞香甲素(1)和三个已知活性二萜,GNIDITRIN(2),土沉香毒素(3)和瑞香毒素(4)以及棕榈酸(5).根据它们的光谱数据和化学反应分别确定其结构.其中化合物1对孕猴中期妊娠引产剂量300微克/只,羊膜控注射给药.     

A rapid and precise microheterometric determination of mercury with p-dimethylamino-benzylidene-rhodanine

1. In citrate or tartrate solutions mercury formed three different compounds with p-dimethyl-amino-benzylidene-rhodanine at pH ~5,~7 and ~9.The composition of the compounds is discussed. 2. Analytical methods are presented for the determination of 0.1 mg mercury in 20 ml solution which contained 99.5–99.9% foreign metals. In most cases the error lay between zero and 1%. The foreign metals were :Ca, Ba, Mg, Zn, Mn, Ni, Co, Al, Cr(III), Fe(III), Cd, Cu, Pb, U(VI), Tl(I), Th, Ce(III), Sb(III) and Bi(III). Methods for the determination of 0.1 mg mercury in gold (III), Pt(VI), Pd(II) and silver are also presented.     

Total arsenic determination and speciation in infant food products by ion chromatography-inductively coupled plasma-mass spectrometry

Health risk associated with dietary arsenic intake may be different for infants and adults. Seafood is the main contributor to arsenic intake for adults while terrestrial-based food is the primary source for infants. Processed infant food products such as rice-based cereals, mixed rice/formula cereals, milk-based infant formula, applesauce and puree of peaches, pears, carrots, sweet potatoes, green beans, and squash were evaluated for total and speciated arsenic content. Arsenic concentrations found in rice-based cereals (63-320 ng/g dry weight) were similar to those reported for raw rice. Results for the analysis of powdered infant formula by inductively coupled plasma-mass spectrometry (ICP-MS) indicated a narrow and low arsenic concentration range (12 to 17 ng/g). Arsenic content in puree infant food products, including rice cereals, fruits, and vegetables, varies from <1 to 24 ng/g wet weight. Sample treatment with trifluoroacetic acid at 100 degrees C were an efficient and mild method for extraction of arsenic species present in different food matrixes as compared to alternative methods that included sonication and accelerated solvent extraction. Extraction recoveries from 94 to 128% were obtained when the summation of species was compared to total arsenic. The ion chromatography (IC)-ICP-MS method selected for arsenic speciation allowed for the quantitative determination of inorganic arsenic [As(III) + As(V)], dimethylarsinic acid (DMA), and methylarsonic acid (MMA). Inorganic arsenic and DMA are the main species found in rice-based and mixed rice/formula cereals, although traces of MMA were also detected. Inorganic arsenic was present in freeze-dried sweet potatoes, carrots, green beans, and peaches. MMA and DMA were not detected in these samples. Arsenic species in squash, pears, and applesauce were not detected above the method detection limit [5 ng/g dry weight for As(III), MMA, and DMA and 10 ng/g dry weight for As(V)].     

液相色谱-串联质谱法测定10种食品中四溴菊酯残留

建立了测定蔬菜、水果、茶叶、大豆等10种食品中四溴菊酯残留的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品以乙酸乙酯(蔬菜、水果、茶叶样品)或乙腈(大豆样品)为提取剂,上层有机相经浓缩、固相萃取小柱净化,流动相定容后,采用HPLC在Agilent ZORBAX Eclipse XDB C18色谱柱上,以甲醇和缓冲盐溶液(0.1%甲酸-10 mmol/L乙酸铵)为流动相进行梯度洗脱分离,以串联质谱在多反应监测(MRM)模式下测定,基质外标法定量。结果表明,四溴菊酯的质量浓度在20～1 000μg/L范围内线性关系良好,相关系数为0.999 8;在0.01、0.02、0.1 mg/kg(粮谷类、茶叶、大豆样品)和0.005、0.01、0.05mg/kg(果蔬类样品)加标水平下的回收率为75%～92%,相对标准偏差(RSDs)为4.0%～12.6%(n=6),定量下限(S/N≥10)为0.01 mg/kg(粮谷类、茶叶、大豆样品)和0.005 mg/kg(果蔬类样品)。该方法不受溴氰菊酯干扰,可直接测定四溴菊酯,克服了以往方法只能测定四溴菊酯和溴氰菊酯总量的不足。     

有机锗化合物的离子色谱法分析研究

研究了３种有机锗化合物：β－羧乙基锗倍半氧化物、β－（α－甲基）羧乙基锗倍半氧化物、二－（β－羧乙基）锗氢氧化物的离子色谱法分离和测定条件。以四硼酸钠溶液为淋洗液,硫酸溶液为再生液,梯度淋洗。３种化合物均达到基线分离,检出限分别为０．０３８,０．０３５和０．０２５ｍｇ／Ｌ（以锗计）。方法已用于保健口服液的测定,加标回收率为９５％～１０１％,其结果与氢化物发生－原子荧光光谱法的结果吻合。     

Separation and determination of trace amounts of beryllium(II), aluminium(III) and chromium(III) with chromotrope 2C chelates by RP-HPLC

A reversed-phase high-performance liquid chromatographic separation and determination of beryllium(II), aluminium(III) and chromium(III) with chromotrope 2C chelates on a C18-bonded stationary phase is reported. Methanol-water (45:55 v/v) containing 6 x 10(-3)M tetra-n-butylammonium bromide (TBAB) and 2 x 10(-2)M acetate buffer solution (pH 6.0) as mobile phase and with spectrophotometric detection at 530 nm was applied. The method has high sensitivity, the detection limits being 0.2 ppb for beryllium(I), 1 ppb for aluminium(III) and 2 ppb for chromium(III). Under the optimum conditions, most other metal ions did not interfere, e.g. up to 2 mg of Hg(II), Sn(II, IV), Pb(II), Bi(III), Ag(I), Zn(II), Cd(II), Cu(II), 1.5 mg of Fe(II), Co(II), Ni(II), 1.2 mg of Ca(II), Mg(II), Sr(II), Ba(II), 1 mg of Ga(III), In(III), 0.5 mg of Fe(III), 1 mg of Ga(III), In(III), 0.5 mg of Fe(III), 0.4 mg of Th(IV), Zr(IV). The method can be applied to the simultaneous determination of trace amounts of beryllium(II), aluminium(III) and chromium(III), in water, rice, flour and human hair samples.     

Development of a liquid chromatography–tandem mass spectrometry method for the determination of Grayanotoxins in rat blood and its application to toxicokinetic study

A sensitive and specific high‐performance liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed for the determination of Grayanotoxin I (GTX I) and Grayanotoxin III (GTX III) in rat whole blood. Grayanotoxins (GTXs) and clindamycin as internal standard (IS) were extracted from rat blood via solid‐phase extraction using PEP solid‐phase extraction cartridges. Chromatographic separation of the analytes was achieved on a Kinetex C₁₈ (100 × 2.1 mm, 2.6 µm) reversed‐phase column using a gradient elution with the mobile phase of 1% acetic acid in water and methanol at a flow rate of 0.2 mL/min. Electrospray ionization mass spectrometry was operated in the positive ion mode with multiple reaction monitoring. The calibration curves obtained were linear over the concentration range of 1–100 ng/mL with a lower limit of quantification of 1 ng/mL for GTXs. The relative standard deviation of intra‐day and inter‐day precision was below 6.8% and accuracy ranged from 94.8 to 106.6%. The analytes were stable in the stability studies. The validated method was successfully applied to the quantification and toxicokinetic study of GTXs in rats for the first time after oral administration of 11.52 mg/kg mad honey and 0.35 mg/kg GTX III, respectively. Copyright © 2014 John Wiley & Sons, Ltd.     

Evaluation of a mixed immunosorbent for selective trace enrichment of phenylurea herbicides from plant material

A mixed immunosorbent, composed of anti-isoproturon and anti-chlortoluron antibodies immobilized on aldehyde-activated silica was evaluated for the trace enrichment and clean-up of several phenylurea herbicides from potatoes, carrots and peas. As the immunosorbent exhibited non-specific interactions with the matrix components, a previous clean-up step based on gel filtration (Sephadex G-25 PD-10 column) or anion-exchange (Power 1 × 8 Dionex column) was necessary. The coupling of gel filtration and immunosorbent with subsequent HPLC/UV determination allowed the determination of selected herbicides in potatoes in the 30 ng/g range with high precision, but for more complex samples (carrots and peas) the combination of anion-exchange resin and immunosorbent was required. With 30 ng/g spiked samples recovery rates for isoproturon, chlortoluron, metobromuron, linuron and chlorbromuron averaged 80 ± 20% (n = 5 in two consecutive days) for the whole procedure and the estimated detection limits ranged from 5 to 20 ng/g.     

液相色谱-串联质谱法快速测定植物源性食品中的百草枯

建立了水果、蔬菜、豆类和粮谷中百草枯残留的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法.用水提取样品中的百草枯,弱阳离子交换(WCX)固相萃取柱(SPE)净化.采用CAPCELL PAK ST色谱柱(150 mm×2.0mm).乙腈-10 mmol/L乙酸铵水溶液(用甲酸调至pH 4.0)为流动相,以电喷雾离...     

气相色谱-串联质谱法测定食用油中两种非邻苯二甲酸酯类增塑剂

建立了气相色谱-串联质谱同时测定食用油中对苯二甲酸二（2-乙基己基）酯和偏苯三甲酸三（2-乙基己基）酯两种非邻苯二甲酸酯类增塑剂的方法。样品采用乙腈提取,于-20℃冷冻除脂净化,用气相色谱-串联质谱选择反应监测模式测定。两种化合物的检出限为0.03 mg/kg,定量限为0.1 mg/kg,线性范围为0.1~10 mg/kg。3个添加水平（0.1、0.3和1.0 mg/kg）下的回收率为81.04%~108.31%,相对标准偏差为0.70%~9.91%。该方法简便、准确,适用于食用油中对苯二甲酸二（2-乙基己基）酯和偏苯三甲酸三（2-乙基己基）酯的检测。     

Analytical applications of m- and p-phenylene-di(1-tetrazoline-5-thione) Gravimetric determination of ruthenium(lll) in presence of large amounts of rhodium (III)

A simple and rapid method is described for the gravimetric determination of ruthenium(III) with two new isomeric reagents, m-and p-phenylene-di(1-tetrazoline-5-thione). Solutions containing milligram amounts of ruthenium(III)on treatment with the acetone or alcohol solutions of the reagents at pH 5.5-7.0 give a quantitative yield of an intensely green insoluble 1:1 complex which can be easily filtered off and dried at 110-115 degrees . Amounts of ruthenium down to 0.5 mg can be determined with fairly good accuracy and precision. Even large amounts of rhodium do not cause any interference. The following cations interfere: Pd(II), Pt(IV), Au(III), Ir(IV), Bi, Fe(III), Cu(II), Hg(I), Hg(II), Pb, Cd, T1(I) and Ag.