高效液相色谱荧光法检测南瓜中色氨酸的含量

目的 采用酶解法处理样品,建立了南瓜中色氨酸的高效液相色谱检测方法。方法 南瓜样品经蛋白酶水解后,经C18色谱柱分离,以甲醇-0.0085mol/L乙酸钠溶液作为流动相等度洗脱,荧光检测器检测,外标法定量。结果 色氨酸在浓度为1.0~ 100mg/L范围内线性关系良好,相关系数(r²)≥0.999,检出限和定量限分别为17mg/kg、 50mg/kg。在低、中、高3个加标水平下的回收率为95.9%~ 100.8%, 相对标准偏差(RSD)为1.11%~ 2.44%。本方法操作简单、便捷,准确度高,重现性好。使用上述方法对18批次南瓜样品进行色氨酸含量检测,色氨酸含量差异较大,新疆喀什种植的特色小南瓜色氨酸含量普遍高于其余品种。     

Determination of bisphenol A in milk and dairy products by high-performance liquid chromatography with fluorescence detection

This study was conducted to develop a selective and sensitive method for the determination of bisphenol A (BPA) levels in milk and dairy products. A method based on solvent extraction with acetonitrile and solid-phase extraction (SPE) was developed for the analysis of BPA in milk, yogurt, cream, butter, pudding, condensed milk, and flavored milk, and a method using two SPE cartridges (OASIS HLB and Florisil cartridge) for skim milk was also developed. The developed methods showed good recovery levels (77 to 102%) together with low detection limits (1 microg/liter for milk, yogurt, pudding, condensed milk, flavored milk, and skim milk and 3 microg/liter for cream and butter). These methods are simple, sensitive, and suitable for the analysis of BPA in milk and dairy products. When 40 milk and dairy products were analyzed by the proposed methods, BPA was not identified in noncanned products, but its levels ranged from 21 to 43 microg/kg in canned products, levels that were 60- to 140-fold lower than the migration limits in the European Union and Japan.     

Determination of carotenoids in foods by high-performance liquid chromatography

The mean values of alpha and beta-carotene of 10 fruits and vegetables from supermarkets in Cairo and Alexandria have been determined using HPLC method, and the average vitamin A activities (in retinol equivalents) calculated. Carrots, spinach and sweet potatoes were the best sources of provitamin A activity. Beta-carotene was the more prevalent carotenoid compared with alpha-carotene. An analysis of variance including all foods investigated demonstrated that there were no significant differences among either locations or times of analysis. There was no difference between the analysed values of vitamin A activity and the USDA Handbook No. 8 values.     

高效液相色谱法测定液态奶中的叶酸

建立了HPLC二级管阵列检测器检测液态奶中叶酸的方法.该法相关系数为O.9996,平均回收率在81.8%～88.77%之间,最低检测限为1.5μg/L.本方法简单、快捷、灵敏,可用于液态奶中叶酸的日常分析.     

高效液相色谱法测定玉米赤霉烯酮的方法研究

以乙腈和NaCl溶液为提取剂提取玉米赤霉烯酮,固相萃取柱净化,高效液相色谱法荧光检测器检测。通过单因素和正交实验,探讨了料液比、乙腈∶NaCl溶液比、NaCl浓度、超声提取时间对提取效果的影响,得到最佳提取条件为料液比25∶100、乙腈∶NaCl溶液比80∶20、NaCl溶液浓度为40g/L、超声提取时间为15min;通过对固相萃取柱净化条件、液相色谱流动相、流速、柱温选择优化,得到以甲醇-水为流动相,甲醇与水比例为65∶35(v/v)、流速为1mL/min、柱温为30℃时,检测效果最好;通过对检测方法日内、日间加标回收实验,得到该检测方法回收率为78.2%～89.6%,相对标准偏差为1.5%～3.9%;检测限为8μg/kg。该方法简便快速,重现性好,适合于玉米赤霉烯酮的实际检测应用。     

Determination of carotenoids in foods by high-performance liquid chromatography.

The mean values of alpha and beta-carotene of 10 fruits and vegetables from supermarkets in Cairo and Alexandria have been determined using HPLC method, and the average vitamin A activities (in retinol equivalents) calculated. Carrots, spinach and sweet potatoes were the best sources of provitamin A activity. Beta-carotene was the more prevalent carotenoid compared with alpha-carotene. An analysis of variance including all foods investigated demonstrated that there were no significant differences among either locations or times of analysis. There was no difference between the analysed values of vitamin A activity and the USDA Handbook No. 8 values.     

Determination of stigmasterol primary oxidation products by high-performance liquid chromatography

A new specific chromatographic method for the determination of plant sterol primary oxidation products, hydroperoxides, was developed. Separation was performed by normal-phase high-performance liquid chromatography (NP-HPLC) using two types of detectors. A UV detector was used as a general detector and a fluorescence detector after post column diphenyl-1-pyrenylphosphine reagent addition (DPPP-FL detection) as a hydroperoxide-specific detector. Stigmasterol was used as a model compound. Hydroperoxides were obtained by photo-oxidation in dichloromethane in the presence of methylene blue as a sensitizer. Specificity of the DPPP-FL detection was confirmed by establishing the structures of the main hydroperoxides by gas chromatography mass spectrometry. 5α-Hydroperoxide, 7α-hydroperoxide and 6α- and 6β-hydroperoxides were identified by comparing mass spectral data and retention times with those of the corresponding hydroxy derivatives of cholesterol. Moreover, the suitability of the method for monitoring the formation of hydroperoxides during photo-oxidation was demonstrated. The results showed that the new NP-HPLC method with DPPP-FL detection provides information about the structures and amounts of different plant sterol hydroperoxides in a sample without prior derivatization, complex sample pre-treatment or heating.     

高效液相色谱法测定腈纶织物中的丙烯腈

优选了腈纶织物丙烯腈的提取剂、高效液相色谱法的柱子、流动相以及检测波长,建立了腈纶织物中丙烯腈的高效液相色谱检测方法.样品以水为溶剂,经超声提取;以V(水)∶V(乙腈)=5∶95为流动相,通过Phenomenex?Luna NH2(150 mm×4.6 mm i.d.,5μm)色谱柱分离;以210 nm为紫外检测波长,采用外标法定量.检测结果显示:丙烯腈在0.1~10.0 mg/L内呈良好的线性关系,最低检出限LOD为0.1 mg/kg,定量检出限LOQ为0.5 mg/kg.该方法回收率为93.0%~100.8%,RSD为4.2%~5.9%.该方法简便、快速,能满足腈纶织物中丙烯腈的测定要求.     

高效液相色谱荧光检测法测定天然维生素E中高分子量多环芳烃

建立了天然维生素E中8种高分子量多环芳烃的高效液相色谱-荧光检测(HPLC-FLD)分析方法.样品通过中性氧化铝柱色谱富集净化后,在XDB-C18反相色谱柱上采用乙腈/水(80:20,v/v)为流动相进行分离,荧光法测定,同时优化了氧化铝柱色谱的洗脱条件.结果显示:8种高分子量多环芳烃的检测限在0.05～0.45ng/g之间,定量限范围为0.18～1.50ng/g,加标回收率在80.8%～104.O%之间,相对标准偏差(RSD)范围为2.0%～9.8%,并且将该法用于天然维生素E中高分子量多环芳烃的测定,均有很好的重复性,RSD小于12.0%.     

Determination of flumequine, nalidixic acid and oxolinic acid in shrimps by high-performance liquid chromatography with fluorescence detection

A simple high-performance liquid chromatography (HPLC) method with fluorescence detection is presented for the determination of the quinolones flumequine, nalidixic acid and oxolinic acid in shrimps. The pharmaceuticals were extracted from the matrix with acetonitrile, purified by liquid–liquid extraction and analysed by HPLC with fluorescence detection at excitation wavelength of 312 nm and emission wavelength of 368 nm. The method has been validated according to the recommendations of the European Commission Decision 2002/657/EC under the consideration of specificity, trueness and precision as well as decision limit CCα and detection capability CCβ. The results of the validation demonstrate that the method is suitable to verify surely quinolone residues in shrimps and to decide with an estimated certainty if the investigated sample complies the European Council Regulation 2377/90/EEC or not. Furthermore, shrimp retail products of the years 2004 and 2005 were investigated with the developed HPLC-method.     

Quantitation of aflatoxins in walnut kernels by high-performance liquid chromatography with fluorescence detection

A total of 85 walnut samples collected between October 2012 and April 2013 in different provinces of Turkey were analysed for the presence of aflatoxins (AFs). The method involved methanol–water extraction, clean-up with immunoaffinity columns and a sensitive high-performance liquid chromatography coupled with fluorescence detection after post-column derivatisation. The method was validated for selectivity, linearity, trueness, precision, limit of detection and limit of quantification (LOQ), which met the performance criteria as set by EC regulation No. 401/2006. LOQs were 0.07, 0.04, 0.09 and 0.05 µg kg^–1 for AFB₁, AFB₂, AFG₁ and AFG₂, respectively. AFs were present in 9.4% of walnut samples (8/85) at total AFs levels ranging from 0.09 to 15.4 µg kg^–1. Only one of eight walnut samples exceeded the European Union limit of 2 and 4 µg kg^–1 for AFB₁ and total AFs, respectively.     

Determination of aldehydes in tequila by high-performance liquid chromatography with 2,4-dinitrophenylhydrazine derivatization

In this work, the determination of aldehydes in different tequila brands was carried out by high-performance liquid chromatography after derivatization with 2,4-dinitrophenylhydrazine. For the comparative purposes, two commercial brandies were also analyzed. The derivatization agent (50 μl of 3.5 mmol l⁻¹ DNPH in HCl, 2 mol l⁻¹) was added directly to the sample (500 μl) and dinitrophenylhydrazones formed were extracted with hexane. After evaporation of the solvent in nitrogen stream, the residues were dissolved in 100 μl of acetonitrile. The calibration standards were prepared from respective dinitrophenylhydrazones, following the same procedure as for beverage samples. Reversed phase chromatographic separation was achieved on Luna C18 column (250 mm×4.6 mm, 5 μm), using gradient elution (acetonitrile:water, from 68 to 80% of acetonitrile in 20 min) and a total flow rate 1 ml min⁻¹. Spectrophotometric detection for furanic aldehydes was at 390 nm (for other aldehydes at 365 nm). The assignation of chromatographic peaks was accomplished by comparison of their relative retention times and UV/Vis spectra with those of external standards. The method of standard addition was also used. The aldehydes identified were 5-hydroxymethylfurfuraldehyde (t _ret=4.1 min), formaldehyde (t _ret=5.1 min), syringaldehyde (t _ret=5.6 min), acetaldehyde (t _ret=6.2 min), 2-furaldehyde (t _ret=7.2 min) and 5-methylfurfuraldehyde (t _ret=8.9 min). At least four chromatographic peaks with retention times higher than 12 min remained unidentified. The quantification results showed drastically higher concentrations of 2-furaldehyde and 5-methylfuraldehyde in tequilas as referred to brandies. Furthermore, 100% tequilas contained higher levels of these two compounds (for four brands analyzed, mean values 18.6 and 5.97 μg ml⁻¹, respectively) as compared to the mixed brands (five brands analyzed, mean values 6.46 and 3.30 μg ml⁻¹). The results obtained confirm that the profile of furanic aldehydes depends on the type of fructans contained in the raw material and also on heating treatment applied or not prior to fermentation. In contrast to other polysaccharides, inulin hydrolyzes at elevated temperature and the contribution of Maillard browning reactions increases the production of furanic compounds. Our results indicate that the levels of 2-furaldehyde and 5-methylfuraldehyde could be used for discrimination between 100% and mixed tequila brands.     

高效液相色谱法对膨化食品中合成色素的测定

研究建立了一种高效液相色谱法同时测定膨化食品中的柠檬黄、苋菜红、日落黄、诱惑红、胭脂红和亮蓝6种合成色素的方法。膨化食品经石油醚脱脂,α-淀粉酶水解,聚酰胺粉净化。采用Waters Symmetry Shield C18色谱柱(4.6mm×250mm,5μm),以甲醇和0.02mol/L乙酸铵为流动相,梯度洗脱,用二极管阵列检测器记录各个色谱峰的紫外吸收光谱,色谱检测波长为254 nm。结果表明,各色素1.0μg/m:~50μg/m L线性关系良好,相关系数为0.9998~0.9999;加标回收率在90.5%~101.2%之间。本方法操作简便,准确可靠,适用于膨化食品中合成色素的测定。     

高效液相色谱-化学发光测定食品中的香兰素

在碱性条件下,香兰素对luminol-K3Fe（CN）6体系有增敏作用。根据这一现象建立了一种经高效液相色谱（HPLC）分离柱后测定香兰素的化学发光法。本方法以C18为色谱柱,用乙腈和水（50∶50,V/V）为流动相,线性范围7.0×10-7⁴.0×10-5mol L-1,检出限为2.0×10-7mol·L-1（3σ）,相对标准偏差为3.9%（c=4.0×10-6mol/L,n=9）。该方法用于食品中香兰素含量的测定,其分析结果与高效液相-紫外光度法（HPLC-UV）比较具有很好的一致性。      

高效液相色谱法测定酸奶中四种有机酸

测定酸奶中风味有机酸,精确评价酸奶风味,并对比3种发酵剂的发酵性能。使用3种直投式发酵剂以半工业化方式生产酸奶,测定3种酸奶在发酵及冷藏过程中的酸度变化,感官评定酸奶成品,并通过高效液相色谱法(HPLC)分析酸奶中的4种有机酸成分(乳酸、柠檬酸、丙酮酸及甲酸)。结果表明:3种发酵剂产酸迅速,所产酸奶品质优良,M与自制发酵剂后酸化弱。冷藏期间3种酸奶中有机酸含量的变化存在细微差异。利用高效液相色谱法有效测定了酸奶中4种有机酸(乳酸、柠檬酸、丙酮酸及甲酸),成功评定了3种发酵剂的发酵性能。     

Determination of ascorbic and dehydroascorbic acid in lean and fatty fish species by high-performance liquid chromatography with fluorometric detection

Ascorbic acid (AA) and dehydroascorbic acid (DHAA) were analysed in fish muscle by high performance liquid chromatography (HPLC) coupled with fluorescence determination using 4,5-dimethyl-o-phenilenediamine (DMPD) as a derivative agent. The use of the DMPD in combination with isobutanol extraction eliminated many matrix interferences and increased significantly the specificity and sensitivity of the method. A strong pH dependence in the derivatization reaction was also demonstrated. Satisfactory results in terms of sensitivity, stability and reproducibility were obtained. The analyses demonstrated that the relative ratio of AA and DHAA in post-mortem fish muscle differs among fish species and seems to be related with the susceptibility to oxidation.     

高效液相色谱示差检测法测定饮料中低分子质量抗性麦芽糊精含量

目的 优化标准方法AOAC 2001.03和GB/T 22224-2008《食品中膳食纤维的测定 酶重量法和酶重量法-液相色谱法》的样品前处理过程,简单、高效、准确地测定饮料中添加的低分子质量抗性麦芽糊精的含量。方法 样品经一定比例稀释后,经色谱柱分离,示差折光检测器测定,内标法定量。结果 方法检出限和定量限分别为0.01 和0.03 g/L,3个添加水平的平均加标回收率为93.2%~96.9%,日内相对标准偏差<1.66%, 日间相对标准偏差 <1.81%。同时考察了市场上常见的添加低分子质量抗性麦芽糊精的茶饮料,碳酸饮料和包装饮用水,测定结果和标签宣称值基本相符,且加标回收率为95.9%~102.3%。结论 本方法样品前处理简单、快速,适用于饮料中添加的低分子质量抗性麦芽糊精含量的测定。     

离子对色谱-ELSD检测麦类中植酸的方法研究

建立了应用离子对色谱-蒸发光散射检测(IPC-ELSD)麦类作物中植酸含量的方法,并结合电喷雾质谱(ESI-MS)分析鉴定了各组分。色谱条件:C18色谱柱(5μm,4.6 mm×150 mm);流动相:甲醇-水(体积比60∶40,含0.4%正戊胺,甲酸调节p H为4.5);流速1.0 m L/min;柱温35℃。结果表明,植酸含量在0.25~5.0 mg/m L范围内线性关系良好(R2=0.999 1),检测限为40μg/m L,平均回收率为90.44%,相对标准偏差为3.13%。该方法快速、准确,适用于麦类中植酸含量的测定。     

利用反相高效液相法测定马乳中的乳清蛋白

乳清蛋白是马乳中主要的蛋白质,不同物种间蛋白质组成存在差异。该研究利用反相高效液相色谱(RP-HPLC)对马乳清中的蛋白进行分离和定量分析,利用基质辅助激光解吸电离飞行时间质谱(MALDI-TOFMS)对主要分离组分进行鉴定。结果表明,马乳乳清蛋白中主要组分为LYS,α-lg和β-lg。利用建立的色谱分析方法对乳清蛋白定量测定结果显示,LYS,α-lg和β-lg在(0.1~1.0)(R~2=0.999 3)、(0.2~0.8)(R~2=0.996 9)和(0.2~1.0)g/L(R~2=0.990 3)线性关系良好。该方法的稳定性、精密度、重现性的相对标准偏差(RSD)均小于5%,加标回收率分别为:88.05%~96.26%,86.03%~95.70%和91.79%~100.97%,能够满足实际检测的需要。测得马乳乳清中的LYS,α-lg和β-lg,含量为别为(3.38±0.32)、(2.64±0.37)及(0.52±0.06)g/L。     

Determination of polysorbates in foods by solid-phase extraction and high-performance liquid chromatography

A simple and rapid method using refractive index high-performance liquid chromatography (RI-HPLC) was developed for the determination of polysorbates (PS) in processed foods. PS were extracted with ethyl acetate containing 5% methanol. The extract was cleaned up on a multimode cartridge (300 mg) and an Alumina-N cartridge (500 mg) to remove fats and food color. HPLC separation was performed on a C18 column (4.6 i.d. x 150 mm) with methanol as the mobile phase. The recoveries of PS80 from nine kinds of foods fortified at the levels 1-5 g/kg were 80-99%. The limit of quantitation for PS80 in foods was 0.10 g/kg. The proposed method was applied to Worcestershire sauce that was PS-positive by TLC, and PS was confirmed to be present as PS80 at the concentration of 0.13 g/kg.