Inter-laboratory validation studies of biological method for determination of streptomycin in royal jelly

Inter-laboratory validation studies were conducted in 6 laboratories to validate the biological method for determination of streptomycin in royal jelly. Streptomycin spiked at the level of 0.2 and 1.0 ppm was analyzed. Mean recoveries were 89 and 96%, reproducibility relative standard deviations (RSD(R)) were 15.0 and 14.0%, HORRAT(R) values were 0.7 and 0.9. Samples containing residues at the levels of 0.25 and 0.80 ppm were analyzed. Mean recoveries were 113 and 99%, RSD(R) were 15.0 and 10.4%, and HORRAT(R) values were 0.8 and 0.6. The determination limit was 0.1 ppm. These results show that this method has good performance.     

Inter-laboratory validation studies of biological method for determination of tetracyclines in royal jelly

Inter-laboratory validation studies were conducted in 5 laboratories to validate the biological method for determination of tetracyclines in royal jelly. Oxytetracycline spiked at the levels of 0.2 and 1.0 ppm was analyzed. Mean recoveries were 88 and 90%, reproducibility relative standard deviations (RSD(R)) were 13.7 and 7.8%, and HORRAT(R) values were 0.7 and 0.5. Samples containing residues at the levels of 0.25 and 0.80 ppm were analyzed. Mean recoveries were 73 and 77%, RSD(R) were 12.6 and 10.5%, and HORRAT(R) values were 0.6 and 0.6. The determination limit was 0.1 ppm (oxytetracycline, tetracycline) and 0.02 ppm (chlortetracycline). These results show that this method has good performance.     

Determination of cholesterol oxidation products in milk powder and infant formulas by gas chromatography and mass spectrometry

In this paper a method for the cholesterol oxidation products (oxysterols) determination in milk powder and infant formulas has been presented. In the sample preparation step lipids transesterification has been performed. The recoveries of oxysterols have been determined and ranged from 94.2% to 99.9% for all but 20a-hydroxy cholesterol (74.2%). Detection limits were 0.018-0.034 ppm and the relative standard deviations (RSD) values were 4.6%-18.3%. The method has been utilized for the determination of oxysterols in milk-based infant formulas and milk powder available on the market. The concentration of oxysterols was between 0.04 and 4.20 ppm of a lipid extract fraction.     

正丙醇作内标气相色谱法测定白酒的酒精度

建立了用正丙醇作内标测定白酒酒精度的气相色谱方法。采用DB-624UI（60 m×0.32 mm×1.8 μm）毛细管色谱柱,氢火焰离子化检测器进行测定。该方法在乙醇体积分数为0.009 98%～0.099 80%范围内线性关系良好,相关系数R2=0.999 9。精密度试验相对标准偏差（RSD）为0.5%,重复性试验RSD为0.5%。加标回收率在96.51%～101.13%,RSD为0.2%～1.8%。结果表明,该方法前处理操作简单、快捷、准确度高、精密度好,适用于白酒酒精度的快速检测。     

香肠中红色2G的HPLC法及UPLC-MS/MS检测

建立香肠中红色2G色素的高效液相色谱法(HPLC)测定和确证的超高压液相色谱-质谱/质谱法(UPLC-MS/MS)。以0.662mol/L氨水为提取液,样品均质提取两次,离心后用C18柱净化,采用高效液相色谱-二极管阵列检测器(HPLC-DAD)检测,流动相为乙酸-乙酸铵缓冲液-甲醇(55:45,V/V),等度洗脱,流速为1mL/min,检测波长为530nm,阳性结果用UPLC-MS/MS确证。HPLC-DAD法在0.0212～1.06mg/L范围内,红色2G的峰面积与其相应浓度呈现良好相关性,r＞0.999,方法测定限为0.106mg/kg,在空白样品中添加已知浓度的红色2G色素,平均回收率在79.0%～86.5%之间,相对标准偏差(RSD)在3.19%～5.06%之间。UPLC-MS/MS法的测定限为0.005mg/kg,平均回收率在75.5%～80.2%之间,RSD在3.62%～9.97%之间。该方法可用于香肠中红色2G的检测及确证。     

超声波辅助-顶空固相微萃取-气相色谱法测定葡萄酒中痕量2,4,6-三氯苯甲醚

建立了超声波-顶空固相微萃取-气相色谱检测葡萄酒中的痕量木塞污染物——2,4,6-三氯苯甲醚（TCA）的方法。试验结果表明,该方法有良好的线性关系,相关系数为0.999 89,方法定量限为0.5 ng/L,相对标准偏差RSD在1.98%～5.32%之间,加标回收率为89.0%～103.2%。该方法操作简便、快速、准确度高、重现性好,适用于普通实验室对葡萄酒中痕量TCA残留的检测。     

牛羊肉中三聚氰胺的HPLC快速检测

建立高效液相色谱(HPLC)检测牛、羊肉中三聚氰胺的检测方法。样品经1% 三氯乙酸- 乙腈(3:1,V/V)提取,利用阳离子交换固相萃取柱净化后,洗脱液于50℃条件下用氮气吹干,残渣用离子对试剂缓冲液- 乙腈(90:10,V/V)溶解,用高效液相色谱法由紫外检测器检测、外标法定量。结果表明,三聚氰胺在0.2～80μg/mL 质量浓度范围内具有良好的线性关系,线性相关系数(R2)为0.9999,其检出限为0.05mg/kg。在牛肉样品中,三聚氰胺的平均回收率为81.73%～83.35%,相对标准偏差为0.97%～1.95%;在羊肉样品中,三聚氰胺的平均回收率为80.95%～82.95%,相对标准偏差为0.70%～2.32%。本方法具有操作快捷、灵敏度高、重现性好等优点。     

高效液相色谱法测定鱼油中的EPA乙酯和DHA乙酯

目的:建立高效液相色谱法分离测定鱼油制品中的二十碳五烯酸乙酯(EPA-EE)和二十二碳六烯酸乙酯(DHA-EE)的方法。方法:采用C18色谱柱(250mm×4.6mm),以乙腈-水(90∶10)溶液为流动相,流速为1.0mL.min-1,检测波长205nm。结果:EPA-乙酯和DHA-乙酯分别在0.00273.40μg和0.0031 3.92μg的范围内呈良好线性,线性回归方程分别为y=46014x+25975(R2=1)和y=27036x+53635(R2=0.9995),EPA乙酯和DHA乙酯平均回收率分别为99.45%和101.78%,相对标准偏差分别为1.84%和2.92%(n=5),鱼油中EPA-乙酯和DHA乙酯的含量分别为8.15%和59.6%。结论:本法简便、快速、重现性好,可用于油脂样品中EPA、DHA乙酯含量测定。     

国内外卷烟主流烟气中氨的分析比较

采用离子色谱法对国内外较有代表性的127种卷烟主流烟气中的氨进行了测定,方法的检测限为13.5 μg/ L , RSD 为4.9% , 空白加标回收率在89%～96%之间。结果表明:国内外卷烟主流烟气氨含量范围约为3.6～14.2 μg/ 支;国内和国外混合型卷烟氨含量的平均值基本相当,国内烤烟型卷烟主流烟气氨含量平均值低于国内外混合型卷烟。      

高效液相色谱-串联质谱法检测鱼肉中5种头孢类药物

建立高效液相色谱-串联质谱法同时检测鱼肉中5 种头孢类抗生素（头孢氨苄、头孢洛宁、头孢匹林、头孢 喹肟和头孢唑啉）残留的检测方法。鱼肉基质经乙腈提取,Prime HLB（6 mL,200 mg）固相萃取小柱净化。采用 AB-4500 Qtrap液相色谱-串联质谱仪,Accucore C18 RP-MS色谱柱（2.1 mm×100 mm,2.7 μm）,以乙腈和体积分 数0.1%的乙酸水溶液为流动相进行梯度洗脱,流速0.4 mL/min,柱温30 ℃。采用电喷雾离子源,正离子扫描,多反 应监测模式,外标法定量。结果表明：5 种头孢类药物在0～75 μg/kg范围内线性良好,且在8 min内完全分离;5 种 头孢类药物的检出限均为0.5 μg/kg,定量限为2.0 μg/kg;在10、25、40 μg/kg加标水平下,5 种头孢类药物的批内平 均加标回收率为81.0%～111.0%,相对标准偏差为0.41%～10.50%,批间平均加标回收率为84.7%～106.0%,相对标 准偏差为0.88%～8.71%。     

基于超高效液相色谱-四极杆-静电场轨道阱高分辨质谱快速测定水果中18种游离氨基酸

本文采用超高效液相色谱-四极杆-静电场轨道阱高分辨质谱（UPLC-Q-Exactive Orbitrap）建立了水果中18种游离氨基酸的快速测定方法。水果样品经粉碎、超声提取、离心、过滤后,使用SHISEIDO CAPCELL PAK BB-H C₁₈色谱柱（2.1 mm×150 mm,3 μm）分离,以0.2%甲酸水溶液和甲醇溶液为流动相进行梯度洗脱,结合保留时间、一级分子离子精确质荷比和二级特征碎片离子对目标化合物进行快速筛查,并准确定量。结果表明,甘氨酸、丙氨酸的线性范围为1~50 nmol/mL,其余16种氨基酸线性范围为0.5~50 nmol/mL,均线性良好（R2≥0.99）,检出限为0.5~1 pmol/g,在1倍、2倍、10倍定量限浓度水平进行加标回收实验,回收率范围为79.1%~118.2%,相对标准偏差（relative standard deviations,RSD）为0.5%~5.6%。该方法简便、快捷、准确,适用于多种水果中18种游离氨基酸成分的测定。     

猪油中磺胺类药物残留量检测研究

建立超高效液相色谱-串联质谱法测定猪油中磺胺类药物残留的方法。试样经正己烷溶解,加入80%乙腈水溶液提取,经PRIME HLB小柱净化后,供超高效液相色谱-串联质谱检测。用甲醇-0.1%甲酸+2 mol/L甲酸铵水溶液为流动相,经质谱多反应监测(MRM)模式检测。结果显示:18种磺胺类药物均有良好的线性关系,相关系数均大于0.99,检出限为0.5μg/mL,回收率在90.1%~100.0%,RSD在0.17%~5.94%。     

电感耦合等离子体-质谱法测定上海市售大米中40种元素含量

目的 建立了电感耦合等离子体质谱法测定大米中Y、La、Ce、Pr、Nd、Sm、Eu、Gd、Dy、Ho、Er、Tm、Yb、Hg、B、K、Mg、Na、Ca、Zn、Mn、Cu 、Fe、Ba、Li、Sr、Cd、Pb、Se、Ni、V、Cr、As、Tl、Be、U、Ag、Co、Cs、Ga 40种元素含量的分析方法,并对60件上海市售大米进行测定。方法 采用5mL浓硝酸、2mL过氧化氢作为消解酸进行微波消解前处理,以选取合适的待测元素质量数和在线内标消除质谱干扰和非质谱干扰。结果 结果表明：该方法线性相关系数均大于0.9995,检出限为0.0001～0.3mg/kg,定量限为0.0003～1.0 mg/kg;三水平加标回收率为在85.6%～121.6%,相对标准偏差为0.5～9.0% (n=6)。选择国家标准物质大米（GSB-1）验证方法的可靠性,待测元素测定值与标准值基本一致。选取国标以原子吸收、原子荧光光谱法与电感耦合等离子体质谱法比对以验证方法准确性,4种元素的标准样和检测样比对结果均一致。结论 该方法高通量、简便快速、准确度好、灵敏度高,线性范围广、精密度好等特点。     

高效液相色谱-串联质谱法测定水产品中7种微囊藻毒素

建立了高效液相色谇串联质谱法同时测定水产品中7种微囊藻毒素（微囊藻毒素-RR、微囊藻毒素-YR、微囊藻毒素-LR、微囊藻毒素-LA、微囊藻毒素-LW、微囊藻毒素-LF、微囊藻毒素．LY）的分析方法。样品用90%醇水（P／g）溶液提取,经离心、固相萃取柱净化后,用C18柱,以0．1％甲酸乙腈．0．1％甲酸溶液为流动相,梯度洗悦分离,使用三重四级杆质谱检测器捡测,以保留时间及特征离子对定性,外标法定量。结果表明,7种微囊藻毒素在线性范围内线性关系良好,相关系数均不低于0．9990,方法的定量限（以信噪比为10计）为0．2-0．5μg／kg,添加水平为1．0-20μg／kg时,回收率为71．5-106％,相对标准偏差（n=6）为312～9．1％。该法前处理简单、回收率高、精密度好,适用于水产品中7种微囊藻毒素的测定。     

顶空-气相色谱法与氢气微电极法用于富氢水中氢气含量的检测

氢气含量为富氢水的关键指标之一，但目前尚无标准检测方法。本文将超饱和富氢水稀释后采用顶空-气相色谱法与氢气微电极法测定了氢气含量，对检测方法进行了条件优化、方法学评价，并对市售富氢水产品进行了氢气含量检测。结果显示，顶空-气相色谱法优化后的顶空进样平衡温度为70℃、平衡时间为20 min。在0～1.61 mg/L氢气含量范围内决定系数(R²)为0.9976，在0.161、0.805、1.449 mg/L添加水平，回收率分别为104.90%、102.22%和97.78%，相对标准偏差(RSD)分别为3.87%、2.29%和1.69%。氢气微电极法在0～1.61 mg/L氢气含量范围内R²为0.9978，在0.161、 0.805、 1.449 mg/L添加水平，回收率分别为96.75%、 95.78%和98.00%,RSD分别为1.84%、0.98%和2.80%。对7种市售罐装富氢水的检测发现，不同产品中氢气含量相差较大，从0.8～6.2 mg/L不等，但均达到现有团体标准的要求。开盖后超饱和富氢水中氢气存留量在30 min内降低约10%,6 ...     

凝胶渗透色谱-高效液相色谱法测定蔬菜中 呋喃丹的含量

目的建立凝胶渗透色谱-高效液相色谱法检测蔬菜中的呋喃丹农药残留量。方法样品经乙腈提取和环己烷-乙酸乙酯溶解后,经凝胶渗透色谱净化和反相高效液相C_(18)色谱柱分离后,采用荧光检测器进行测定,荧光检测激发波长为285 nm,发射波长为320 nm,采用高效液相色谱法以外标法定量。结果呋喃丹在0.2~5.0 ng/mL浓度范围内呈良好线性关系,相关系数r大于0.999,检测限为0.01 mg/kg。对空白蔬菜样品进行呋喃丹3个浓度水平0.5、1.0和2.0 mg/kg的加标,回收率结果为78.3%~97.6%,相对标准偏差为3.26%~11.69%。结论本研究所建立的方法简单、灵敏度高,可适用于蔬菜中的呋喃丹农药残留的分析检测。     

水产品中六溴联苯测定方法的建立及应用分析

建立水产品中痕量水平六溴联苯（hexabromobiphenyls,HexaBBs）的气相色谱检测方法,并对HexaBBs在不同水产品中的蓄积差异性进行特征分析。对前处理方法的提取试剂、超声时间、固相萃取小柱以及毛细管色谱柱的类型进行优化。结果表明,乙酸乙酯为提取试剂、超声时间为10 min,采用硅胶柱净化,经配有DB-17MS色谱柱的气相色谱分析效果最佳。5 种HexaBBs在0.20～10.00 ng/mL质量浓度范围内线性关系良好,线性相关系数均大于0.998,方法检出限为0.50 μg/kg,定量限为1.00 μg/kg。在1.00、5.00 μg/kg水平下加标回收率在77.15%～118.14%之间,相对标准偏差在0.56%～13.32%之间。本方法可用于定量分析水产品中残留的痕量HexaBBs,并且发现HexaBBs在不同营养级的水产品间存在蓄积性差异。     

Gas chromatographic determination of pesticide residues using electron-capture detector and mass spectrometry

The sensitive and reliable method for determination of 6 pesticides, cyanazine (triazine), uniconazole (azole), diflufenican (nicotinilide), vernolate (thiocarbamate), bromoxynil (hydroxyl benzonitrile), and asulam (sulfanilyl carbamate) were examined and validated. The methods based on solid-phase extraction (SPE) and gas chromatograph (GC) with electron capture detection (ECD). Confirmation analysis of pesticides was carried out by GC-MS in the selected ion monitoring (SIM) mode using 2 target ions. Method validation was performed at 5 fortification levels (0.005, 0.01, 0.05, 0.1, and 0.5 mg/L). The linearity of the calibration curves was excellent in matrix matched standards, and yielded the coefficients of determination (R ²)≥0.9982 for all target analytes. The limit of quantification (LOQ) was 0.05 mg/L for 6 pesticide compounds and the reporting level of the method, defined as lower than the maximum residue levels established by Korea Food & Drug Administration (KFDA). Average recoveries of the pesticides spiked at 0.05, 0.1, and 0.5 mg/L into 3 agricultural products, rice, apple, and soybean were in the range 76.40–120% with relative standard deviation (RSD) values ≤11.07% for all compounds, respectively.     

超声波提取- 液相荧光法测定水果中壬基酚聚氧乙烯醚及其降解产物

为建立超声波提取热带水果中环境激素壬基酚聚氧乙烯醚及降解产物壬基酚、液相荧光法测定残留量的方法,对超声提取的温度、时间、功率进行条件优化,提取液经净化浓缩后,用C18 色谱柱进行分离,液相色谱荧光法进行测定。结果表明：样品中壬基酚聚氧乙烯醚及壬基酚在0.5～50μg/mL 范围内线性良好,检出限分别为0.04mg/kg 和0.008mg/kg,方法回收率分别为92%～102% 和75%～92%。该方法快速灵敏、准确度高,符合残留检测的要求。     

Rapid and simultaneous determination method for analysis of minerals in infant formula using ICP-MS

A rapid and simultaneous method by using inductively coupled plasma mass spectrometry (ICP-MS) was developed for determination of 19 elements in infant formula. Fast and efficient sample digestion was achieved by a microwave-assisted nitric acid procedure. An acetic acid was added to both these treated solutions and standard solutions as a countermeasure for carbon charge transfer in As, Se elements. The observed calibration curves showed good linearity (r(2)>0.9993) and the quantification limit was low. The recoveries of elements were 95.0-108% and the relative standard deviations (RSD) of this method were 0.3-4.2%. The analyzed values were in good agreement with the certified values in a NIST standard reference material. This study showed that the ICP-MS method is useful for major to trace multi-elemental determination in infant formula.