高效液相色谱法测定糕点、糖果、月饼中的 2-(4-甲氧基苯氧基)丙酸钠

目的采用高效液相色谱法测定糕点、糖果和月饼中的2-(4-甲氧基苯氧基)丙酸钠的含量。方法样品经超声提取后,采用Diamonsil C_(18)色谱柱分离,以甲醇:乙腈:水(50:10:40,V:V:V,pH=3)为流动相,在柱温为25℃、流速为0.8 m L/min的条件下进行洗脱,采用二极管阵列检测器在波长224 nm下对食品中2-(4-甲氧基苯氧基)丙酸钠进行检测,以外标法定量。结果在0.50~200 mg/L浓度范围内,2-(4-甲氧基苯氧基)丙酸钠具有良好的线性关系;该方法定量限为0.01 g/kg,检出限为0.003 g/kg;加标浓度水平为1.000 mg/L时,糕点、糖果和月饼平均加标回收率分别为92.8%~95.8%、95.3%~96.8%和94.0%~98.5%,重复性试验的相对标准偏差分别为3.5%~4.5%、2.8%~3.8%和3.0%~4.8%(n=10)。结论该方法具有较高的准确性和良好的重现性,适合食品中2-(4-甲氧基苯氧基)丙酸钠的测定。     

高效液相色谱法测定酱油中组胺的含量

目的建立丹磺酰氯柱前衍生-高效液相色谱法测定酱油中组胺含量的方法。方法样品酱油以1,7-二氨基庚烷作为内标,用正丁醇:三氯甲烷(1:1,V:V)萃取净化,经丹磺酰氯衍生,乙醚萃取后氮气吹干,用乙腈定容,高效液相色谱仪测定,内标法定量。结果组胺含量在1~100 mg/L线性关系良好,线性相关系数r=0.9999,检出限为0.5 mg/kg。在精密度实验中,其相对标准偏差为2.59%~6.48%,在1.0、10.0、50.0 mg/kg的添加水平下,加标回收率为88.0%~104.2%。结论该方法线性关系好、检出限低、稳定性好、回收率高、测定结果准确,适合酱油中组胺的测定。     

高效液相色谱法测定马铃薯和土壤中的辛硫磷残留

目的建立高效液相色谱法测定马铃薯和土壤中辛硫磷残留的分析方法。方法样品经乙腈萃取,氨基固相萃取小柱净化,采用以色谱柱Agilent ZARBAX SB-C_(18) 柱(4.6 mm×250 mm,5μm)分离,甲醇/水(75:25,V:V)为流动相等度洗脱后紫外检测器检测,检测波长为280 nm。结果辛硫磷在0.05~10 mg/L浓度范围内线性关系良好(r~2=0.9990);最低检出限为0.02 mg/kg,辛硫磷在马铃薯块茎、植株和土壤中的添加水平为0.05~5.0 mg/kg时,添加回收率分别为92.3%~102.4%、98.5%~109.1%和89.7%~104.3%,相对标准偏差分别为1.0%~2.5%、1.4%~5.6%和1.4%~2.1%。结论该方法具有快速、准确、灵敏度高等特点,符合国家标准对食品中农药残留测定的要求。     

柱前衍生高效液相色谱法检测水产品中甲醛的含量

目的建立柱前衍生高效液相色谱法检测水产品中甲醛含量。方法样品经绞碎匀浆后,经2,4-二硝基苯肼-乙酸钠缓冲液衍生液(1:1,V:V)于60℃衍生1 h,冰浴冷却后的衍生物直接上高效液相色谱检测,以ODS-C_(18)柱子为分离柱,甲醇-水(70:30,V:V)为流动相等度洗脱,二极管阵列检测器在365 nm波长处检测,外标法定量。结果甲醛在0~10 mg/L浓度范围内线性关系良好,线性相关系数为0.9994,方法检出限为0.5mg/kg。空白样品在1.0、5.0和20.0 mg/kg添加水平下,回收率在88.2%~95.3%之间,RSD在0.75%~1.82%之间。对水产品9种样品中的甲醛进行了测定,其中6个样品检出甲醛,含量范围为1.51~64.04 mg/kg。结论该方法简便、灵敏、准确,可适用于水产品中甲醛含量的分析。     

气相色谱-串联质谱法检测花生油中的250种 农药残留

目的建立气相色谱-串联质谱法同时测定花生油中250种农药残留的分析方法。方法样品经酸化乙腈提取,以乙腈+甲苯(3:1,V:V)作为洗脱液经C_(18)固相萃取柱净化,采用DB-5MS毛细管色谱柱分离;质谱采用电子轰击离子源模式电离,多反应监测模式对样品进行测定。结果本方法分为7组,完成250种目标化合物的分离分析。250种农药残留在0.02~0.2 mg/L范围内呈现良好的线性关系,相关系数r为0.990~0.999;样品中添加5、10和20μg/kg 3个浓度水平的250种农药混标工作液进行加标回收试验,平均回收率为70%~130%,RSD为1.8%~8.9%(n=5),检出限为5~10μg/kg。结论该方法准确、灵敏、重现性好、高通量,适合测定花生油中的多种农药残留。     

流动注射法快速测定乳粉中的亚硝酸盐及硝酸盐

采用在线透析和在线镉柱还原-流动注射法测定乳粉中的硝酸盐和亚硝酸盐。方法基于测定亚硝酸盐与磺胺、N-(1-萘基)乙二胺二盐酸盐形成偶氮染料的吸光度,硝酸盐经过在线镉柱还原为亚硝酸盐,得到硝酸盐与亚硝酸盐含量的总和。该方法的RSD值仅为4.06%,亚硝酸盐检出限为0.011 mg/kg,硝酸盐的检出限为0.129 mg/kg,亚硝酸盐在0.75~2.00 mg/kg范围内的加标回收率在98%~106%之间,硝酸盐在9.24~61.60 mg/kg范围内的加标回收率在98%~105%之间,样品测定速度为30样/h。此方法极为简单快捷,对实际乳粉的亚硝酸钠、硝酸钠含量的测定结果令人满意。     

三重四级杆串联质谱法测定乳粉类产品中 5种核苷酸的含量

目的建立超高效液相色谱-三重四级杆串联质谱法测定乳粉类产品中5种核苷酸,包括胞嘧啶核苷酸(cytidine monophosphate,CMP)、尿嘧啶核苷酸(uridine monophosphate,UMP)、腺嘌呤核苷酸(adenosine monophosphate,AMP)、鸟嘌呤核苷酸(guanosinemonophosphate,GMP)、次黄嘌呤核苷酸(inosinemonophosphate,IMP)含量的分析方法。方法样品经温水溶解后,经1%(V:V)甲酸沉淀蛋白离心后,分别通过固相萃取SPE法和超滤离心法有效净化其他干扰成分,从而进行前处理方法评价;采用Waters ACQUITY UPLC HSS T3(2.1mm×50 mm,1.8μm)为分析柱,0.1%(V:V)甲酸水溶液和乙腈作为流动相,等度洗脱分离。质谱采用正离子模式,多反应监测模式(MRM)进行检测,对纯水配制标准溶液和阴性基质溶液配制标准溶液进行比较,外标法定量分析。结果 5种核苷酸在4.5 min内达到基线分离,AMP、IMP和GMP在10~1000.0 ng/mL浓度范围内线性关系良好,CMP和UMP分别在25~1000 ng/mL和100~1000 ng/mL浓度范围内线性关系良好,相关系数均在0.9990以上,方法检出限分别为UMP 5 mg/kg、CMP 1 mg/kg、AMP0.5 mg/kg、IMP 0.5 mg/kg、GMP 0.1 mg/kg。在10.0、50.0、100.0mg/kg加标水平下的超滤离心法的平均回收率在73.6%~110.9%之间,相对标准偏差(RSD)为3.56%~15.89%;SPE法的平均回收率在86.4%~109.5%之间,相对标准偏差(RSD)为2.32%~14.45%。结论该方法灵敏度高,可以快速准确鉴别并定量乳粉产品中的核苷酸。     

高效液相色谱法测定番茄中腐霉利和异菌脲的 残留量

目的建立固相萃取-高效液相色谱法测定番茄中腐霉利和异菌脲的残留量。方法番茄样品用乙腈超声提取,加入氯化钠进行盐析脱水,提取液过Florisil柱净化,用正己烷/丙酮(90:10,V:V)淋洗液洗脱,洗脱液氮吹近干,甲醇定容后经ZORBAX Eclipse XDB-C_(18)(250 mm×4.6 mm,5μm)色谱柱进行分离,以乙腈/水(60:40,V:V)为流动相,流速为1.0 m L/min,采用二极管阵列检测器检测,检测波长为208 nm。结果在0.05~5.0 mg/L浓度范围内,腐霉利和异菌脲的质量浓度与其峰面积呈良好的线性关系(r~20.999),方法检出限均为0.025 mg/kg,在0.05、0.5和1.0 mg/kg 3个不同加标水平上,腐霉利和异菌脲的加标回收率为90.6%~102.4%,精密度为3.72%~6.55%。结论该方法操作简单、准确,可应用于番茄中腐霉利和异菌脲的检测。     

液相色谱法测定茶氨酸提取物中咖啡因的含量

目的建立一种快速、简便测定茶氨酸提取物中咖啡因的液相色谱方法。方法样品经过前处理,以1-癸烷磺酸钠溶液(1.22 g→850 m L)+乙腈+磷酸=850+150+1(V:V:V)为流动相,流速1.0 m L/min,柱温40℃,进样量10μL,等度洗脱,经Agilent C18柱分离,于280 nm波长处检测,以外标法定量。结果用本方法进行检测,能很好的分离咖啡因,在浓度0.001 mg/m L至0.05 mg/m L之间呈现良好的线性关系,方法的相关系数可达1.000,平均回收率为100.2,在95%~105%之间,相对标准偏差(RSD)为1.0%,定量限为92.78μg/g,检出限为29.03μg/g。结论该方法耗时短、操作简便、准确、重现性好、分离效果明显。可以应用于茶氨酸提取物中咖啡因含量的测定。     

液相色谱-质谱法测定乳及乳制品中氯霉素类抗生素的含量

目的建立液相色谱-质谱法测定乳及乳制品中氯霉素类抗生素的残留量。方法液态奶、酸奶、奶粉样本经乙酸乙酯提取,经Waters Sep-pak C_(18)固相萃取小柱净化,至Agilent C_(18)(150 mm×2.1 mm,5μm)色谱柱分离,以乙腈:水(50:50,V:V)为流动相进行等度洗脱。质谱法采用电喷雾离子源负离子模式和多反应监测模式测定,以内标法定量。结果氯霉素、甲砜霉素、氟苯尼考3种待测物质在0.1~20 ng/m L范围内线性关系良好,线性相关系数都在0.9995以上;氯霉素的检出限为0.011~0.021μg/kg,甲砜霉素的检出限为0.042~0.100μg/kg,氟苯尼考的检出限为0.010~0.018μg/kg;氯霉素在0.05、0.5和1μg/kg 3水平上的加标回收率为83.1%~95.6%,甲砜霉素在0.1、1和2μg/kg 3水平上的的加标回收率为80.2%~102.1%,氟苯尼考在0.05、0.5和1μg/kg 3水平上的的加标回收率为81.3%~103.5%;氯霉素的相对标准偏差为4.4%~6.4%,甲砜霉素的相对标准偏差为4.1%~7.1%,氟苯尼考的相对标准偏差为3.7%~6.6%。结论本方法准确灵敏,适用于乳及乳制品中氯霉素类抗生素残留量的测定。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press