Determination of organochlorine compounds in fatty matrices: Application of normal-phase LC clean-up coupled on-line to GC/ECD

Off-line normal-phase LC has been used for the clean-up of compounds in our laboratory for several years. On-line coupling of this LC system, which typically yields 12 ml fractions, is not possible due to its large fraction volume. The maximum transfer volume in on-line LC-GC/ECD is approx. 300 μl. Therefore down-scaling of the LC system was attempted in order to reach these low fraction volumes. Miniaturization resulted in a 240 μ1 LC fraction containing the analytes of interest, which is transferred to GC/ECD via an on-column interface. Sensitivity requires that a minimum amount equivalent to 1–2 mg of sample should reach the GC detector; the selectivity is determined by the separation between the matrix and the last eluting target analyte. For the analysis of fatty samples, limitations were observed in the separation of dieldrin from triglycerides. Other organochlorine compounds, e.g. polychlorobiphenyls (PCBs), the DDT group, HCB and the HCHs can be analyzed with RSDs of 2–4 % (n = 10) at concentration levels of sub-μ/kg in milk fat using a 3 μm Hypersil silica 50 × 1.0 mm i.d. LC column.     

全二维气相色谱-电子捕获检测器法分析土壤中毒杀芬同类物的残留

建立了全二维气相色谱-电子捕获检测器(GC× GC-μECD)检测土壤中毒杀芬同类物的分析方法.以非极性的DB- XLB(20 m×0.25 mm×0.25 μm)为第一色谱柱,中等极性的BPX-50(2 m×0.1 mm×0.1 μm)为第二色谱柱,对土壤中23种高关注毒杀芬同类物进行了分离鉴定,并采用基质曲线外标法进行定量分析.本方法在1～200,μg/L浓度范围内,毒杀芬同类物的线性相关系数(r2)均大于0.99,方法检出限(S/N=3)为0.039～0.482 μg/L,基质加标毒杀芬同类物的回收率为55％～115％,相对标准偏差(RSD)均小于30％(n=5).利用本方法对毒杀芬污染的土壤样品进行了测定,获得了较好的分离效果.     

Application of programmable temperature vaporisation injection with resistive heating-gas chromatography flame photometric detection for the determination of organophosphorus pesticides

The combination of a programmable temperature vaporisation (PTV) injector with resistive heating GC (RH-GC), a form of fast GC, has been applied to the analysis of organophosphorus (OP) pesticides. The PTV injector was optimised in the 'at-once' solvent vent mode for the injection of ethyl acetate (10-40 microL) or ACN (10 microL). The short RH-GC column (5 m x 0.25 mm ID) with fast temperature ramps (up to 153 degrees C/ min) allowed the separation of a total of 20 OP pesticides in less than 6 min. Average recoveries between 67 and 119% were obtained for pesticides spiked at 0.01 mg/kg into apple and pear matrix. Extraction of orange juice with ACN provided higher recoveries (92-104%) for methamidophos, acephate and omethoate compared to ethyl acetate (62-73%). Results for analysis of OP pesticides in samples containing incurred residues were in good agreement with those obtained using GC-MS. The overall method was rapid, allowing 20 samples to be analysed in 4 h.     

HPLC法快速筛查抗风湿类中成药或保健食品中21种非法添加化学成分

基于亚3μm核壳填料色谱柱技术建立了高效液相色谱法快速筛查21种抗风湿类化合物。供试品以1%乙酸-甲醇为提取溶剂,经ACCHROM C18100A(4.6 mm×100 mm,2.8μm)分离,以磷酸水溶液(pH3.0)-甲醇-乙腈溶液为流动相,梯度洗脱,检测波长为230 nm,流速1.0 m L/min,柱温35℃。该方法在20 min内可分离21种成分,各化合物的线性范围为5~100μg/m L(萘普生为1.5~30μg/m L),回收率为91.0%~109.1%。萘普生的检出限(S/N=3)为0.8 mg/kg,其余化合物的检出限为2.0 mg/kg。按上述方法对抽检样品进行检测,发现18批阳性样品,并采用液相色谱-质谱联用法进一步确证。该方法快速、准确,适用于抗风湿类中成药或保健食品中非法添加化学成分的快速筛查,具有广阔的应用前景。     

顶空气相色谱-质谱法测定涂料中的5种挥发性有机物

建立了涂料中5种挥发性有机物(VOCs)的顶空气相色谱-质谱(HS/GC-MS)分析方法.对溶剂、平衡温度、平衡时间、GC-MS的分离检测等实验条件进行了优化.涂料样品经N,N-二甲基甲酰胺(DMF)-水(1 :1,体积比)溶解分散,经90 ℃、90 min静态顶空后,通过DB-VRX色谱柱分离和质谱检测,外标法定量....     

卷烟主流烟气粒相物中中性化学成分的全二维气相色谱飞行时间质谱(GC×GC-TOF MS)谱图特征识别

建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析卷烟主流烟气中中性化学成分的方法。以较长的弱极性柱HP-5MS(50 m×0.2 mm i.d.×0.33μm)作为第一维柱,较短的薄液膜中等极性柱DB-17MS(1.7 m×0.1 mm i.d.×0.1μm)作为第二维柱,对优质烟叶单料卷烟烟气的中性成分进行定性分析,经过人工纠错等分析初步鉴定出匹配度大于700的1 464种成分,重点讨论了中性香味羰基化合物全二维点阵的谱图特征,为烟气和复杂体系的深入研究提供了方法学基础。     

高效液相色谱法对水果中多菌灵与福美双残留的同时测定

建立了高效液相色谱同时测定水果中多菌灵和福美双残留量的方法。样品经二氯甲烷提取,OasisHLB固相萃取柱净化后,经C18色谱柱分离,甲醇-0.05 mol/L甲酸铵溶液(60∶40,体积比)洗脱,紫外检测器进行检测。结果表明,多菌灵、福美双的的线性范围分别为0.01~10.0、0.05~10.0 mg/kg,相关系数分别为1.0、0.9999,检出限分别为0.005、0.03 mg/kg,平均加标回收率为80%~109%。该方法成功用于市售水果样品的测定。     

在线液相-气相二维色谱高灵敏测定卷烟主流烟气中的4-（N-甲基亚硝胺基）-1-（3-吡啶基）-1-丁酮

建立了在线液相-气相二维色谱测定卷烟主流烟气中4-(N-甲基亚硝胺基)-1-(3-吡啶基)-1-丁酮(NNK)的方法。 NNK 的分析在在线凝胶气质联用仪上进行,采用自行装填的微型碱性氧化铝柱,并把仪器上的凝胶柱换成氧化铝柱,用于 NNK 的分析。捕集有主流烟气总粒相物的剑桥滤片用二氯甲烷提取,以 D4-NNK 为内标,提取液经微型氧化铝柱分离,含 NNK 的部位切割进入气相色谱,排干溶剂后启动气相色谱升温经毛细管柱进行分离,用质谱检测。本方法将烟气国标方法 NNK 测定中的氧化铝柱色谱净化和气相色谱-质谱分析在线连接起来,可不经样品前处理净化直接进样分析;每次进样可达40μL,是常规气相色谱-质谱分析最大进样量(2.0μL)的20倍,显著提高了分析灵敏度。方法线性范围达1.2~120 ng/ mL,相关系数为r=0.9998,回收率为93.9%~96.0%;检出限和定量限分别为0.25 ng/ mL 和0.9 ng/ mL,样品分析结果与中国烟草总公司企业标准方法进行对比,结果相符合。     

液相色谱-电喷雾串联质谱法同时测定蜂胶保健品中的活性成分和降糖西药

采用超高效液相色谱-电喷雾串联四极杆质谱仪(UPLC-ESI-MS/MS)同时测定蜂胶保健品中14种活性成分和9种违禁降糖西药。蜂胶保健品样品用甲醇稀释,超声波提取,样品溶液经高速离心后过滤。使用ACQUITY UPLC C18反相柱(50 mm×2.1 mm,1.7μm);流动相为0.3%甲酸溶液和乙腈,在梯度条件下分析,目标分析物在多反应监测(MRM)模式下以保留时间和离子对(母离子和两个碎片离子)信息比较进行定性和定量分析。本方法的活性成分检出限(LOD)为0.7～42.0 mg/kg;定量限(LOQ)为2.2～140 mg/kg;活性成分的加标回收率为77.8%～113.6%;违禁降糖西药的LOD为0.1～0.9 mg/kg,LOQ为0.3～2.5 mg/kg;违禁降糖西药的平均回收率为79.3%～108.5%。本方法简便、有效、灵敏,为评价蜂胶保健品质量提供了新的检测方法。     

丙丁梭菌萃取发酵产物的气相色谱分析

建立了3种溶剂中产物丙酮、乙醇、正丁醇的气相色谱分析方法。色谱条件为:DB-624色谱柱(30 m×0.32 mm,1.8μm)及FFAP色谱柱(30 m×0.32 mm,0.25μm),FID检测器,程序升温,氮气为载气。采用内标法定量,内标物为异丁醇,进样体积1μL。丙酮、乙醇、正丁醇的浓度与色谱峰面积线性相关,相关系数为0.997 43~0.999 97,测定结果的相对标准偏差为0.19%~2.01%(n=5),回收率为95.1%~101.2%。     

改进QuEChERS-气相色谱-质谱法快速分析测定农用土壤中多环芳烃

建立农用土壤中16种多环芳烃的改进QuEChERS快速提取净化方法及气相色谱-质谱检测方法,并通过对西安市周边农用土壤样品的分析,调查土壤中多环芳烃的污染情况.土壤样品用KOH饱和的甲醇碱化处理后,用丙酮-正已烷(1+1)为提取溶剂,涡旋混匀后超声提取,提取液按改进QuEChERS方法加入无水MgSO4、硅胶及正丙基乙二胺(PSA)进行净化,检测时选用DB -5 MS(30m×0.25 mm×0.25 μm)色谱柱分离,EI电离源及离子监测模式检测,16种多环芳烃的测定低限0.7～3.2μg/kg,加标回收率79.8％ ～ 109.6％,相对标准偏差均低于9.4％.检测的农用土壤样品中均检出有不同程度的多环芳烃残留,约16.7％的土壤样品为轻度污染.     

Factors influencing chromatographic data in fast gas chromatography with on‐column injection

The use of larger volume injection with on‐column injection and fast GC commercial instrumentation was evaluated with the model mixture of n‐alkanes of a broad range of volatility (C₁₀–C₂₈). The presented configuration allows introduction of 40–80‐fold larger sample volumes without any distortion of peak shapes compared to “usual” fast GC set‐ups using narrow‐bore columns. A normal‐bore retention gap (1–5 m×0.32 mm ID) was coupled to a narrow‐bore (5 m×0.1 mm ID×0.4 μm film thickness) analytical column using a standard press‐fit connector. The connection was tight and reliable, and hence suitable for hydrogen as carrier gas. The effect of pre‐column and analytical column connector, injection volume, pre‐column length, column inlet pressure, and analyte volatility on peak shape, peak broadening, and focusing are discussed. The precision of chromatographic data measurements and peak capacity under optimised temperature programmed conditions for fast separations with large volume injection were found to be very good. The presented fast GC set‐up with on‐column injection extends the applicability of the technique to trace analysis.     

QuEChERS/液相色谱-串联质谱法同时测定鱼肉中30种激素类及氯霉素类药物残留

建立了鱼肉中8种雌激素、5种雄激素、6种孕激素、8种糖皮质激素及3种氯霉素类药物多残留的QuEChERS/液相色谱-串联质谱(LC - MS/MS)同时测定方法.均质样品用水分散后加乙腈提取,经分散固相萃取净化后,采用ZORBAX Extend-C18色谱柱(100 mm ×2.1 mm,3.5 μm)分离,分别在电喷...     

Determination of p,p′-DDE and PCBs in adipose tissues using high-performance liquid chromatography coupled on-line to capillary GC – the EURAMIC study

Long-term exposure to fat-soluble xenobiotics is assessed by the concentration of DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethyl-ene], the persistent metabolite of DDT, in subcutaneous fat, aspirated from the buttocks of breast cancer patients and age-matched controls, from five European centers collaborating in a case-control study on breast cancer. In such studies using sample material of living subjects only small amounts of samples can be made available for analysis. In this particular study the only sample material available for the analysis of DDE were aliquots of the aspirates that were originally analyzed for fatty acids. Due to the small sample quantities available, e.g. aliquots of 200–800 p. 1, on-line LC-GC is most convenient because a major part of the sample can be used in the analytical procedure. In the LC-GC procedure 50 μl of sample was injected on the LC column resulting in a 180 μl fraction containing the analytes of interest. The LC fraction was transferred to a capillary GC with electron capture detector by means of partially concurrent solvent evaporation. This way, sample handling is minimized thus reducing losses and preventing contamination. The feasibility of the on-line LC-GC system for the analysis of DDE is demonstrated with the analysis of 634 adipose tissue extracts in different series. The validity of this approach, using samples already analyzed for another parameter, with LC-GC is clearly demonstrated by the fact that in over 97% of the samples DDE can be quantified. Thus rendering a meaningful data-set for further epidemiological evaluation. The DDE levels found ranged from 0.99–3.13 μg/g adipose tissue.     

Analysis of steryl esters in cocoa butter by on-line liquid chromatography-gas chromatography.

On-line liquid chromatography-gas chromatography (LC-GC) has been applied to the analysis of steryl esters in cocoa butter. Separation of the steryl esters was achieved after on-line transfer to capillary GC. HPLC removes the large amount of triglycerides and pre-separates the components of interest, thus avoiding time-consuming sample preparation prior to GC analysis. The identities of the compounds were confirmed by GC-MS investigation of the collected HPLC fraction and by comparison of the mass spectra (chemical ionization using ammonia as ionization gas) to those of synthesized reference compounds. Using cholesteryl laurate as internal standard, steryl esters were quantified in commercial cocoa butter samples, the detection limit being 3 mg/kg and the quantification limit 10 mg/kg, respectively. Only slight differences in percentage distributions of steryl esters depending on the geographical origin of the material were observed. The patterns were shown to remain unchanged after deodorization. The method described might be a valuable tool for authenticity assessment of cocoa butter.     

气相色谱-质谱法测定玩具中的4种阻燃剂

建立了玩具中三(2-氯乙基)磷酸酯、磷酸三邻甲苯酯、2,2′,4,4′,5-五溴联苯醚、2,2′,3,3′,4,4′,6,6′-八溴联苯醚等4种阻燃剂的气相色谱-质谱分析方法。玩具样品以V(正己烷):V(二氯甲烷)=1:1混合溶液为提取溶剂,超声提取30min,提取液以DB-5HT石英毛细管色谱柱(15m×0.25mm×0.10μm)分离后进行选择离子监测模式下的定性及定量分析。4种阻燃剂的定量限为0.1mg/kg,在低、中、高3个添加水平范围内,4种阻燃剂的平均回收率为93.5%～97.3%,相对标准偏差在2.4%～4.1%之间。     

Development of a liquid chromatography tandem mass spectrometry method for simultaneous determination of eight adulterants in slimming functional foods

A method for simultaneous determination of eight adulterants including two appetite suppressants, two energy expenditure-enhancing drugs, one diuretic and three cathartics in slimming functional foods by high performance liquid chromatography with electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) was established. After samples were ultrasonically extracted with 70% (v/v) methanol aqueous solution and centrifuged, the components of ephedrine, norpseudoephedrine, fenfluramine, sibutramine, clopamide, emodin, rhein, and chrysophanol in sample solution were separated by a Hypersil Gold column (2.1 mm × 150 mm, 5 μm) using a programmed gradient elution. A mobile phase consisting of 0.02% (v/v) formic acid-ammonium formate buffer solution (pH=3.50) and methanol was used for elution with a flow rate set at 250 μL/min and column temperature of 25 °C. Qualitative determination was based on characteristic ion pairs and retention time of the targeted compounds using SRM (selective reaction monitoring) mode. Clenbuterol and ibuprofen were internal standards in positive and negative ionization mode, respectively. The internal standard curves were used for quantification measurement. The average recoveries of three different concentrations were from 80.2% to 94.5%. The limits of detection (LODs) were from 0.03 to 0.66 mg/kg (except chrysophanol 1.6 mg/kg). The linear dynamic range covered from 1 to 500 μg/L (except chrysophanol 50-5000 μg/L) for the twelve samples analyzed. Adulterants in four different kinds of slimming functional foods were determined by this developed method, and satisfactory results were obtained. These experimental results showed that, adulteration of sibutramine or/and fenfluramine were the major adulterating components with contents varying from 6.1 to 1.3×10(3) mg/kg and 1.9 to 9.7×10(3) mg/kg, respectively. In addition, three cathartic compounds were detected in six of those tested samples, and ephedrine, norpseudoephedrine and clopamide were not detected in all samples.     

液相色谱-串联质谱法同时测定纺织品和食品包装材料中的壬基酚、辛基酚和双酚A

建立了纺织品和食品包装材料中壬基酚、辛基酚和双酚A的液相色谱-串联质谱分析方法。不同类型的纺织品和食品包装材料样品采用加速溶剂萃取法,以无水乙醇为提取剂,在10.3 MPa和120℃下静态循环提取2次,提取液经Supelclean Envi-Carb石墨化碳黑固相萃取柱净化,收集甲醇-二氯甲烷(1∶4,V/V)洗脱液,采用Waters XBridge C18色谱柱,以甲醇-0.1%氨水溶液为流动相,梯度洗脱分离后,在LC/MS/MS多反应监测模式下进行定性与定量分析。壬基酚、辛基酚和双酚A的方法检出限为0.5μg/kg,在0.5～10μg/kg的3个添加水平范围内,纺织品样品的平均回收率为86.9%～92.5%,相对标准偏差均小于9.1%;食品包装材料样品的平均回收率为87.8%～93.0%,相对标准偏差均小于8.8%。本方法准确、快速、灵敏度高,可用于纺织品和食品包装材料的实际检验。     

Determination of methanol in cosmetics by headspace and multidimensional gas chromatography with mass spectrometric detection

A novel, reliable, and robust analytical method using headspace and multidimensional GC coupled to MS was successfully developed for determining the methanol content in cosmetics. The methanol was quantitatively analyzed and confirmed by heart-cutting multidimensional GC and mass selective detection in full scan mode. The average recovery was 99.8% with an RSD of 4.3%; the LOQ was 5 mg/kg. The proposed method showed good accuracy and precision while minimizing erroneous results due to false positives compared with conventional single-column GC analysis.     

Rapid and sensitive analysis of three polyphenols in tobacco by CE using homemade C(4) D with a mini detection cell

A rapid, sensitive, and practical CE with C(4) D detection was developed for the analysis of three polyphenols (rutin, scopoletin, and chlorogenic acid) in tobacco samples. The constructed mini detection cell (12 mm × 10 mm × 10 mm) of C(4) D featured with small inner cell volume (～2 nL), smaller noise (<0.9 mV), repeatability, high strength and durableness. Three polyphenols were ultrasonically extracted with methanol-water (70:30, v/v) solution following SPE cleanup. The CE method was optimized with the running buffer of 150 mmol L(-1) 2-amino-2-methyl-1-propanol (pH 11.2), and the applied separation voltage of +20 kV over a capillary of 50 μm id × 375 μm od × 50 cm (38 cm to the C(4) D window, 41.5 cm to the UV detector window), which gave a baseline separation of three polyphenols within ca. 6 min. The method provided the limits of quantification (S/N = 10) at about 0.08-0.15 μg g(-1) for three polyphenols, whereas the overall recoveries ranged from 82% to 88%. The proposed method has been successfully applied to measure three polyphenols in the actual tobacco samples, and their contents were calculated and evaluated.