Determination of deoxynivalenol in whole wheat flour and wheat bran

A liquid chromatographic (LC) method was developed for determining deoxynivalenol (DON) in whole wheat flour and wheat bran. A 15 g test sample was extracted with acetonitrile-water (84 + 16, v/v) and applied to a Romer MycoSep cleanup column. The eluate was dried and then reconstituted in a 0.1 M phosphate buffer, pH 7.0, and applied to a Vicam DONtest-LC cleanup column. The methanol eluate was chromatographed with a methanol-water (17 + 83, v/v) mobile phase on a C18 column with UV detection at 220 nm. Five replicates at each of 5 fortification levels (0.25, 0.50, 1.0, 2.0, and 4.0 ppm), plus 5 controls, were determined for both whole wheat flour and wheat bran. For flour, the average recoveries were 72.2-91.5% with relative standard deviations (RSDs) of 4.9-18.4%. The intra-assay flour recovery was 82.4% with 9.8% RSD. A 5 replicate sample of naturally incurred wheat had an average of 1.1 ppm DON with 6.7% RSD. For bran, average recoveries of fortified samples were 69.5-99.7% with RSDs of 1.7-18.8%. The intra-assay bran recovery was 81.5% with 8.9% RSD. The limit of detection (about 3x noise) for the method is 0.05 ppm; the correlation coefficient (linearity) was >0.9995. The DON peak was clearly identified and easily integrated in the chromatograms.     

Determination of paeoniflorin, ferulic acid and baicalin in the traditional Chinese medicinal preparation Dang-Guei-San by high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of paeoniflorin, ferulic acid and baicalin in the traditional Chinese medicinal preparation Dang-Guei-San, which contains Paeoniae Radix, Swertiae Herba, Cnidii Rhizoma and Scutellariae Radix, was established. The samples were separated with a Cosmosil 5C₁₈-AR column by gradient elution with 0.03% (v/v) phosphoric acid- acetonitrile (0 min 96:4, 5 min 84:16, 7 min 82:18, 14–30 min 78:22) as the mobile phase at a flow-rate of 1.0 ml/min, with detection at 245 nm. Methylparaben was used as the internal standard and three equations were derived showing linear relationships between the peak- area ratios of marker components (paeoniflorin, ferulic acid and baicalin) to methylparaben and concentration. The recoveries of paeoniflorin, ferulic acid and baicalin were 27.86, 33.89 and 49.31%, respectively. The repeatability (relative standard deviation) was generally less than 5% (n = 5). The effects of various processes such as concentration by reduced-pressure evaporation, freeze-drying and spray-drying were studied and commercial concentrated herbal preparations containing Paeoniae Radix, Swertiae Herba, Cnidii Rhizoma and Scutellariae Radix were also analysed.     

Measurement of water absorption capacity in wheat flour by a headspace gas chromatographic technique

The purpose of this work is to introduce a new method for quantitatively analyzing water absorption capacity in wheat flour by a headspace gas chromatographic technique. This headspace gas chromatographic technique was based on measuring the water vapor released from a series of wheat flour samples with different contents of water addition. According to the different trends between the vapor and wheat flour phase before and after the water absorption capacity in wheat flour, a turning point (corresponding to water absorption capacity in wheat flour) can be obtained by fitting the data of the water gas chromatography peak area from different wheat flour samples. The data showed that the phase equilibrium in the vial can be achieved in 25 min at desired temperature (35°C). The relative standard deviation of the reaction headspace gas chromatographic technique in water absorption capacity determination was within 3.48%, the relative differences has been determined by comparing the water absorption capacity obtained from this new analytical technique with the data from the reference technique (i.e., the filtration method), which are less than 8.92%. The new headspace gas chromatographic method is automated, accurate and be a reliable tool for quantifying water absorption capacity in wheat flour in both laboratory research and mill applications.     

基于真菌毒素污染差异的液相色谱-串联质谱法鉴别板栗粉中掺假小麦粉

建立了分散固相萃取-超快速液相色谱-串联质谱法同时测定板栗粉和小麦粉中43种真菌毒素的方法,对48份板栗粉和80份小麦粉样品的污染状况进行调查,筛选出5种专属于小麦粉的标志性真菌毒素.样品采用84％(v/v)乙腈水溶液提取,提取液采用C18结合增强型脂质去除净化剂(EMR-Lipid)净化,采用响应曲面-中心组合设计优...     

Isolation of Ferulic Acid from Wheat Bran with a Deep Eutectic Solvent and Modified Silica Gel

Five deep eutectic solvents (DESs) were synthesized with choline chloride and glycerol at ratios from 1:1 to 1:5 and used to extract ferulic acid from wheat bran. The DES with choline chloride:glycerol at a 1:2 molar ratio (DES-2) provided the highest extraction yield. The optimal extraction conditions for DES-2 were obtained using response surface methodology with a yield of 5.86?mg?·?g^?1 ferulic acid. The DES-2 was used to modify silica gel and purify ferulic acid from wheat bran by solid-phase extraction (SPE). The yields were compared for silica gel and silica gel modified with ionic liquid. The recoveries for ferulic acid were 64.1, 89.7, and 80.3%, respectively. Silica gel modified with DES-2 provided the highest recovery. The materials were characterized by infrared spectroscopy and scanning electron microscopy. The DESs were used as extraction solvents and to modify silica gel for SPE, expanding their use in the isolation of ferulic acid from wheat bran.     

Optimization of a chemical modifier in the determination of selenium by graphite furnace atomic absorption spectrometry and its application to wheat and wheat flour analysis.

A method for the determination of total selenium in wheat and wheat flour using graphite furnace atomic absorption spectrometry (GFAAS) with palladium/ascorbic acid as a chemical modifier was studied. The effects of nickel nitrate, palladium/ascorbic acid, and palladium/magnesium nitrate as chemical modifiers on the sensitivity in the determination of selenite, selenate and selenomethionine by GFAAS were compared. The palladium/ascorbic acid modifier was used for the determination of total selenium in wheat and wheat flour, because the oxidation states of the selenium ion are not important in the determination. The detection limit was estimated to be 1 microg L(-1) (calculated as 3sigma of the blank); the calibration curve was linear for the concentration range 5 - 50 microg L(-1) and the recovery range was 96.66 - 101.80%. The optimal ashing and atomizing temperatures were 1300 degrees C and 2250 degrees C, respectively. The proposed method was successfully applied to the determination of total selenium in wheat and wheat flour.     

离心沉淀气相色谱法测定面粉中过氧化苯甲酰含量的研究

建立了离心沉淀,气相色谱氢火焰离子化检测器测定面粉中过氧化苯甲酰含量的方法。考察了不同提取时间和采用不同工作曲线对过氧化苯甲酰测定的影响。试样在石油醚中被冰乙酸还原成苯甲酸,经HP-5（30m×0．25mm×0．25μm）毛细管气相色谱柱分离,氢火焰离子化检测器测定。方法的线性范围为0．005～0．08g／L（r=0．9992）,检出限（S／N=3）为2mg／kg。在添标水平为0．06、0．18和0．30g／kg时的平均回收率为82．70％～89．46％,相对标准偏差为3．77％～6．93％。该方法仪器设备简单,测定结果灵敏、准确,适合面粉中过氧化苯甲酰的测定。     

基于拉曼光谱成像的食品中化学添加剂的无损检测

基于拉曼光谱成像技术对小麦粉中过氧化苯甲酰和L-抗坏血酸进行快速、 无损、 原位检测, 并对2种添加剂的空间分布进行了可视化研究. 采用实验室自行搭建的线扫描式拉曼光谱成像系统, 激发光源波长为785 nm, 有效光谱范围为0~2885.7 cm^-1. 分别在小麦粉中添加含量为0.1%~30%的过氧化苯甲酰和L-抗坏血酸, 对制备的样品进行拉曼光谱扫描, 选取感兴趣区域的光谱信号进行平均, 得到平均光谱代表该样品的拉曼信息. 分别选取过氧化苯甲酰和L-抗坏血酸的2个特征峰, 与该物质在小麦粉中的含量建立线性关系, 其决定系数R²分别为0.9828 和0.9912. 采集的特征波段拉曼图像经过自适应迭代重加权惩罚最小二乘(airPLS)方法扣除荧光背景后, 选取合适的特征峰强度作为阈值, 对校正拉曼图像进行二值化分析, 得到添加物的空间分布可视化图像. 该方法与点检测拉曼技术相比, 具有检测结果准确且检测时间较短的优势, 且可以实现不均匀样品中多种物质的同时检测与分布可视化.     

基于超高效液相色谱-高分辨质谱的非衍生化法测定面粉和燕麦中草甘膦及氨甲基膦酸残留

建立了固相萃取-超高效液相色谱-高分辨质谱（UPLC-HRMS）快速准确测定面粉和燕麦中残留草甘膦（GLY）及其代谢物氨甲基膦酸（AMPA）的分析方法。面粉和燕麦样品经水涡旋和超声提取,用混合阳离子交换固相萃取（MCX）小柱净化与乙腈沉淀蛋白质后,以5 mmol/L乙酸铵水溶液（pH=10.5）和乙腈溶液作为流动相在Dikma Polyamino HILIC色谱柱（150 mm×2.0 mm,5 μm）上进行梯度洗脱与分离,采用电喷雾电离源、负离子模式和平行反应监测（PRM）模式下,内标法定量分析。系统优化了液相色谱与高分辨质谱等仪器条件和样品前处理条件对GLY及其代谢物AMPA测定的影响,并比对了不同分析方法的基质效应,研究了进样系统残留。实验结果表明,GLY和AMPA在5.0~100.0 μg/L范围内呈现良好的线性关系（线性相关系数R²>0.999）,检出限分别为0.005和0.05 mg/kg;低（0.1 mg/kg）、中（0.5 mg/kg）、高（2.0 mg/kg）3个添加水平下,GLY和AMPA的加标回收率分别为93.8%~115%和89.8%~110%,相对标准偏差均小于10%。基质效应实验结果表明,利用同位素内标物能有效降低方法的基质抑制效应（基质效应参数|η|<3%）;进样系统的残留率小于1.0%。本方法与文献报道的衍生化法方法进行比对,结果表明,两种检测方法与靶值的相对偏差分别为2.19%和3.07%。将该方法用于弗帕斯（FAPAS）能力验证样品的测定（编号为09122,燕麦中GLY的测定）,结果满意,测定值与真值之间的偏离程度（z值）=0.2。FAPAS质控样品（编号为T09119QC,面粉中GLY的测定）检测结果显示本方法的准确度为102.2%。该方法具有快速、简便、灵敏和准确等优点,适合面粉与燕麦样品中GLY及其代谢物AMPA的日常监测。     

在线扫集-胶束毛细管电动色谱法测定扛板归中的阿魏酸、咖啡酸和原儿茶酸

采用在线扫集-胶束毛细管电动色谱法(sweeping-MEKC)分离测定扛板归中的阿魏酸、咖啡酸和原儿茶酸。采用未涂层熔融石英毛细管(50 cm×50μm,有效柱长36 cm);环境温度25℃;缓冲体系为20 mmol/L NaH2PO4-80mmol/L十二烷基磺酸钠(SDS)-12.5%乙腈(V/V)(pH 2.20),紫外检测波长为216 nm,运行分离电压-20 kV,进样时间100 s。在优化条件下,3种有机酸均在20 min内出峰,峰面积RSD均小于5%。检出限分别达到98.52,118.73和27.27μg/L。     

高效液相色谱-串联质谱法测定食品中的矮壮素与缩节胺残留

建立了食品中矮壮素和缩节胺2种植物生长调节剂的高效液相色谱-电喷雾电离串联质谱(HPLC-ESI MS/MS)分析方法.样品经甲醇-水(1:1,体积比)提取后,采用Strata-X-C萃取小柱净化,再经Agilent ZORBAX RX-SIL(1.8μm,3.0 mm×100 mm)色谱柱分离,以乙腈和10 mmol...     

Assay of free ferulic acid and total ferulic acid for quality assessment of Angelica sinensis

Activity of Chinese Danggui (DG), the processed root of Angelica sinensis (Oliv.) Diels, is linked to the ferulic acid content but the stability of ferulic acid during extraction for medicinal use is not known. The stabilities of ferulic acid and coniferyl ferulate were evaluated in the extracts of DG using a variety of extraction solvents. These included various combinations and proportions of methanol, water, formic acid, 1 M aqueous hydrochloric acid and 2% sodium hydrogen carbonate (NaHCO3) in water. Coniferyl ferulate was found liable to hydrolyze into ferulic acid in neutral, strongly acidic and basic solvents, where heat and water could facilitate this hydrolysis. However, the hydrolysis was relatively resisted in weakly organic acid. Based on the stability evaluation, two new terms, namely: free ferulic acid and total ferulic acid, were suggested and defined. Free ferulic acid refers to the natural content of ferulic acid in herbs. Total ferulic acid means the sum of free ferulic acid plus the amount of related hydrolyzed components. Meanwhile, the high-performance liquid chromatographic (HPLC) method was developed to assay free ferulic acid and total ferulic acid in DG using methanol-formic acid (95:5) and methanol-2% NaHCO3 in water (95:5) as extraction solvents, respectively. Ten DG samples were investigated on their contents of free and total ferulic acid. The results indicated that the amount variety of free ferulic acid was larger than that of their counterparts, and the ratio of total ferulic acid to free ferulic acid was 4.07 +/- 2.73 (mean +/- SD, n = 10). The chemical assay of DG using total ferulic acid content would be a better choice to assess the herbal quality and was recommended.     

高效液相色谱-二极管阵列检测法测定小麦粉及面粉改良剂中福美双

福美双是重要的二硫代氨基甲酸酯(DTC)杀菌剂,在小麦中使用限量以1 mg/kg二硫化碳(CS₂)计。目前我国相关检测方法是针对二硫代氨基甲酸酯一类的化合物,二硫代氨基甲酸酯通过与酸反应生成CS₂,采用光谱法或色谱法测定CS₂,间接实现二硫代氨基甲酸酯测定。该方法无法特异性实现对福美双的检测,因此开展小麦粉中福美双检测方法的研究具有重要意义。研究建立了高效液相色谱-二极管阵列检测(HPLC-DAD)测定小麦粉及面粉改良剂中福美双的分析方法。小麦粉及面粉改良剂样品用乙腈溶剂提取后,经涡旋、振荡、冰水浴超声和静置后取上清液过滤,供高效液相色谱测定。采用ZORBAX plus-C18色谱柱(150 mm×4.6 mm, 5 μm)分离,以水-乙腈为流动相洗脱分析,在波长280 nm下检测。实验优化了提取溶剂及其体积、振荡超声条件、色谱柱、检测波长、流动相等条件。该方法采用保留时间和紫外光谱图定性,外标法定量。该方法在线性范围内(0.30~30.0 μg/mL)线性关系良好,相关系数(r²)为0.99999。对小麦粉及面粉改良剂进行1.5、3.0、15 mg/kg 3个水平的加标回收试验,福美双的回收率为89.6%~98.3%,相对标准偏差为1.6%~3.9%(n=6)。方法的检出限和定量限分别为0.5 mg/kg和1.5 mg/kg。该方法采用溶剂提取,操作简单,分析时间短,特异性好,具有精密度高、重复性好、检出限低等特点,适用于小麦粉及面粉改良剂中福美双快速、准确的定量检测。     

Phenolic compounds and the antioxidant activity of the bran,flour and whole grain of different wheat varieties

Total phenolic content and DPPH radical scavenging capability of the bran layer, flour made from endosperm and whole grain of wheat were determined. Fifteen different wheat samples of ten spring and five winter wheat varieties were analyzed. The spring wheat varieties were grown in both conventional and organic conditions. The total phenolic content of the bran layer found to be the highest (1258-3157 μg/g), followed by that of grains (168 - 459 μg/g) and the lowest of flour (44 - 140 μg/g). The bound phenolic acids were quantified by CE-DAD analysis after alkaline hydrolysis. Ferulic acid was a major compound among phenolic acids found in wheat varieties.     

A fast and reliable method for the quantitative determination of benzimidazoles and metabolites in milk by LC-MS/MS with on-line sample treatment

A method to detect the presence of common wheat in durum wheat flour samples was developed and tested. Flour samples, or ground wheat samples, were digested by pepsin and chymotrypsin, and the peptide mixture obtained was analyzed by LC/ESI-MS and LC/ESI-MS/MS, which led to the identification of two marker peptides. One peptide was coded only in the DD genome, and thus present only in common wheat; the second was present in all wheat samples (both common and durum), so it was used as marker of the total wheat content. The ratio of the chromatographic areas of these two peptides, as determined by LC/ESI-MS, was related to the proportion of common wheat in the sample using a calibration curve that was constructed with standards of known composition. The proportions of common wheat in samples obtained by mixing different common and durum wheat varieties were accurately determined by this method. Finally, the method was applied in a survey of several durum wheat flour brands present on the Italian market. The results of the survey revealed that contamination of durum wheat flour with common wheat is commonplace.     

微透析与高效液相色谱在线联用技术校正大鼠皮下阿魏酸线性探针

采用微透析与高效液相在线联用技术(MD-HPLC on-line)建立并验证大鼠皮下阿魏酸微透析线性探针体内外校正方法.以磷酸盐缓冲溶液为灌流液,微透析灌注液流速为2 μ L/min,10孔自动进样阀间隔为8 min,在以Hypersil-C18(250 mm×4.6 mm,5μm)为色谱柱,流动相为甲醇-水(含0.5％乙酸)(35∶ 65,V/V),流速1 mL/min,检测波长314 nm的HPLC色谱条件下进行在线检测,阿魏酸在0.1～80 mg/L范围内回归方程线性关系良好,A=159044C-2607 (r=1),阿魏酸日内精密度RSD分别为0.8％,0.3％和0.5％(n=5);日间精密度RSD分别为0.2％,0.3％和0.4％(n=5),重现性与稳定性RSD分别为0.7％和1.1％(n=5).增量法和减量法测定阿魏酸线性探针体内外回收率分别为47.23％±0.94％和20.37％±1.37％,阿魏酸适宜进行微透析实验.应用MD-HPLC on-line对中药当归阿魏酸进行测定,使取样、进样和分析监测同时进行.     

Simultaneous determination of chlorogenic acid, caffeic acid, ferulic acid, protocatechuic acid and protocatechuic aldehyde in Chinese herbal preparation by RP-HPLC

In the present study, a reversed phase high performance liquid chromatographic (RP-HPLC) method was established for simultaneous determination of chlorogenic acid, caffeic acid, ferulic acid, protocatechuic acid and protocatechuic aldehyde in a Chinese herbal preparation (Fufang-Pugongying-Mixture). The separation was performed on a Hypersil ODS-2 column by isocratic elution with methanol and 0.2 M acetate buffer (pH 3.6) (15 : 85, v/v) as the mobile phase at the flow-rate of 1.0 ml/min with operating temperature of 30 degrees C, and detection wavelength of 300 nm. A good linear regression relationship between peak-areas and concentrations was obtained over the range of 2-200 microg/ml for the five marker compounds mentioned above. The spike recoveries were within 96.72-104.07%. The variation coefficient (CV) values of the precision were in the range of 0.89-4.50%. Moreover the developed method has reference value for quantitative analysis of Taraxacum, Lonicera and Angelica.     

Preparation and homogeneity characterization of ten agricultural/food reference materials for elemental composition

Summary Ten agricultural/food reference materials (RM): bovine muscle powder, corn starch, hard red spring wheat flour, soft winter wheat flour, whole milk powder, wheat gluten, corn bran, Durum wheat flour, whole egg powder and microcystalline cellulose, were prepared by milling, irradiation, sieving, blending and packaging procedures. Homogeneity tests for 14 elements in randomly selected units were performed by the initiating laboratories by application of various analytical methods. Al, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn were determined by acid digestion flame atomic absorption spectrometry, and Cd, Co, Ni and Pb using acid digestion graphite furnace atomic absorption spectrometry after separation/preconcentration of the analytes by co-precipitation. In addition, the extensive set of analytical results obtained from the interlaboratory cooperative characterization campaign was assessed to provide homogeneity estimates for other elements. Measures of homogeneity were estimated from the within-laboratory precision from the more precise laboratories. All materials exhibited acceptable homogeneity for virtually all 29 elements (Al, As, B, Ba, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, I, K, Mg, Mn, Mo, N, Na, Ni, P, Pb, Rb, S, Se, Sr, V, Zn) for which best estimate concentration values were available, an essential pre-requisite in establishing reference values for these materials. Sixty-two percent of all homogeneity coefficients of variation (CV) were below 5%, with Br, Ca, Cl, Mg, Na, P, Zn and especially K and N exhibiting very high homogeneity CV less than 1% in some cases.Contribution no. 92–148 from Centre for Land and Biological Resources Research     

RP-LC Determination and Pharmacokinetic Study of Ferulic Acid and Isoferulic Acid in Rat Plasma After Taking Traditional Chinese Medicinal-Preparation: Guanxinning Lyophilizer

A sensitive, simple, and accurate method for determination and pharmacokinetic study of ferulic acid and isoferulic acid in rat plasma was developed using a reversed-phase column liquid chromatographic (RP-LC) method with UV detection. Sample preparations were carried out by protein precipitation with the addition of methanol, followed by evaporation to dryness. The resultant residue was then reconstituted in mobile phase and injected into a Kromasil C₁₈ column (250 × 4.6 mm i.d. with 5 μm particle size). The mobile phase was methanol-1% formic acid (33:67, v/v). The calibration plots were linear over the range 5.780–5780 ng·mL⁻¹ for ferulic acid and 1.740–348.0 ng·mL⁻¹ for isoferulic acid. Mean recoveries were 85.1% and 91.1%, respectively. The relative standard deviations (RSDs) of within-day and between-day precision were not above 15% for both of the analytes. The limits of quantification were 5.780 ng·mL⁻¹ for ferulic acid and 1.740 ng·mL⁻¹ for isoferulic acid. This RP-LC method was used successfully in pharmacokinetic studies of ferulic acid and isoferulic acid in rat plasma after intravenous injection of Guanxinning Lyophilizer.

     

RP-LC Determination and Pharmacokinetic Study of Ferulic Acid and Isoferulic Acid in Rat Plasma After Taking Traditional Chinese Medicinal-Preparation: Guanxinning Lyophilizer

A sensitive, simple, and accurate method for determination and pharmacokinetic study of ferulic acid and isoferulic acid in rat plasma was developed using a reversed-phase column liquid chromatographic (RP-LC) method with UV detection. Sample preparations were carried out by protein precipitation with the addition of methanol, followed by evaporation to dryness. The resultant residue was then reconstituted in mobile phase and injected into a Kromasil C₁₈ column (250 × 4.6 mm i.d. with 5 μm particle size). The mobile phase was methanol-1% formic acid (33:67, v/v). The calibration plots were linear over the range 5.780–5780 ng·mL^?1 for ferulic acid and 1.740–348.0 ng·mL^?1 for isoferulic acid. Mean recoveries were 85.1% and 91.1%, respectively. The relative standard deviations (RSDs) of within-day and between-day precision were not above 15% for both of the analytes. The limits of quantification were 5.780 ng·mL^?1 for ferulic acid and 1.740 ng·mL^?1 for isoferulic acid. This RP-LC method was used successfully in pharmacokinetic studies of ferulic acid and isoferulic acid in rat plasma after intravenous injection of Guanxinning Lyophilizer.