化妆品中丙二醇含量的检测方法研究

建立同时测定化妆品中1,2-丙二醇和1,3-丙二醇的气相色谱(GC)分析方法。样品中的丙二醇用无水乙醇振荡提取,在-10℃下,以10000r/min离心5min后进样,经毛细管色谱柱(ZB-624,30m×0.32mm×0.25μm)分离,氢火焰离子化检测器测定,外标法定量,并采用气质确证。方法学研究结果表明1,2-丙二醇和1,3-丙二醇分别在2.00～500 ug/ml范围内呈良好的线性关系,相关系数分别为0.9999和09993,方法的定量限分别为10mg/kg和8mg/kg,在50、100、200mg/kg三个添加水平下,1,2-丙二醇和1,3-丙二醇的平均回收率为85.7%～101.5%,相对标准偏差(RSD)为2.43%～3.78%(n=6)。本方法前处理技术简单快捷,灵敏度高、重现性好,可用于化妆品中1,2-丙二醇和1,3-丙二醇的同时检测,结果比较满意。     

气相色谱-质谱法测定蚝油中3-氯-1,2-丙二醇含量的不确定度评定

本文根据JJF1059-1999《测量不确定度评定与表示》,按照GB/T5009.191-2006《氯丙醇的测定方法》,采用气相色谱-质谱法测定蚝油中3-氯-1,2-丙二醇含量,建立数学模型,分析其不确定度来源,计算扩展标准不确定度。     

顶空-气相色谱法测定卷烟主流烟气粒相物中吡啶

为研究气相色谱测定卷烟主流烟气粒相物中吡啶含量,采用碳酸钠水溶液作基质校正剂,通过顶空进样、DB-WAXETR色谱柱分离、火焰离子化检测器检测。结果表明:吡啶在0.20~16.20μg/mL质量浓度范围内线性拟合度为0.9998,加标回收率在98.4%~104.7%之间,定量限为0.08μg/支,RSD小于5%,该方法可以快速、准确地测定卷烟主流烟气粒相物中吡啶。     

顶空-气相色谱法检测婴儿脖圈氯乙烯单体含量

建立顶空-气相色谱联用测定婴儿脖圈中氯乙烯单体的检测方法。对顶空条件以及气相色谱条件进行优化。在优化的条件下测得氯乙烯单体的检出限为0.2mg/kg,线性相关系数大于0.99,加标回收率为103%～110%,相对标准偏差(RSD)为1.48%～3.85%。     

顶空-气相色谱法测定水质中的醇类与酮类

建立了顶空-气相色谱法,即直接在密闭的顶空瓶中进水样方法测定生活饮用水及其水源水及废水中醇与酮类化合物(甲醇、乙醇、丙酮、丁酮)的分析方法。在样品采集和色谱分析方法实现了统一,减少了有毒有害有机试剂的消耗和二次污染,通过对各仪器技术参数优化,实现快速分离,并且在8min内获得了组分间良好的分离度,缩短了分析周期。本方法最低检出限在0.01mg/L-0.07mg/L,标准偏差为0.003mg/L-0.0222mg/L,相对标准偏差为0.52%-5.77%,加标回收率为83.2%~103%。     

气相色谱法测定食品包装中残留1,1-二氯乙烷含量的不确定度评定

在气相色谱法测定食品包装中残留的1,1-二氯乙烷含量过程中,对可能引入的不确定度进行了评定,并分析量化了不确定度来源。结果显示:由标准溶液产生的不确定度分量最大,其次是用标准曲线求1,1-二氯乙烷含量,再次是测量重复性,这三项是该法测定结果不确定度的重要来源。当1,1-二氯乙烷测量结果为23.6mg/kg时,其扩展不确定度为2.1334mg/kg(k=2)。     

溶剂解吸-气相色谱法测定空气中苯含量测量不确定度评定

在实际测定空气中苯的含量的过程中,影响测定准确性的因素较多,如何控制这些因素,降低测定过程的误差,是做好测定工作的关键。通过对溶剂解吸-气相色谱测定空气中苯的不确定度进行分析,可以找出其主要的影响因素。所以有必要对其进行评价，以如实反映测量的置信度和准确性。     

《YC／T207-2006〈卷烟条与盒包装纸中挥发性有机化合物的测定 顶空-气相色谱法〉和YC263-2008〈卷烟条与盒包装纸中挥发性有机化合物的限量〉实施指南》

卷烟条、盒包装纸均是用量较大的烟用纸质包装材料,有些产品的印刷工艺比较复杂,对卷烟产品品质具有重大影响。为控制条、盒包装纸中有机溶剂的残留,维护消费者利益,避免潜在的环境污染,国家烟草专卖局组织制定了YC／T207-2006《卷烟条与盒包装纸中挥发性有机化合物的测定 顶空-气相色谱法》和YC263-2008《卷烟条与盒包装纸中挥发性有机化合物的限量》两项烟草行业标准,并分别于2006年10月和2008年7月发布实施。     

基质固相分散萃取-气相色谱同时测定茶叶中有机氯及拟除虫菊酯类农药残留

建立了气相色谱-电子捕获检测器(GC-μECD)同时测定茶叶中14种有机氯和8种拟除虫菊酯类农药残留。采用基质固相分散(Matrix Solid Phase Disperse,MSPD)技术对茶叶样品进行前处理,用气相色谱-电子捕获检测器快速定性定量分析。MSPD集提取、过滤、净化于一步完成,避免了样品均化、转溶、乳化、浓缩造成待测农药组分的损失,大大提高了方法的准确性和精密度。添加回收实验结果表明:22种农药的平均回收率为83.5%~112.6%,相对标准偏差为2.5%~10.6%,方法检出限为0.002~0.02mg/kg。该方法灵敏度、准确度和精密度均符合农药残留测定的要求。     

高效液相色谱法同时测定爆珠壁材中8种水溶性着色剂

建立高效液相色谱-二极管阵列检测器(HPLC-PDA)同时快速测定卷烟爆珠壁材中8种水溶性着色剂(柠檬黄、苋菜红、胭脂红、日落黄、诱惑红、亮蓝、酸性红、赤藓红)的方法。以热水为溶剂将烟用爆珠壁材置于恒温水浴中超声提取,提取液离心后用0.45μm的水相滤膜过滤制得待测溶液。采用优化后的色谱条件对待测溶液进行分析,色谱柱为Zorbax SB-C18色谱柱(150 mm×4.6 mm,5μm),甲醇/乙酸铵水溶液为流动相进行梯度洗脱,12 min内即可完成检测,根据标准曲线即可计算爆珠壁材中着色剂的含量。通过考察,该方法的回收率(n=5)为82.8%~101.4%,相对标准偏差(RSD)为0.3%~9.7%,定量限为3.0~41.0 mg/kg,方法简单,能同时、快速检测出烟用爆珠壁材中8种水溶性着色剂,该方法的建立可为卷烟开发及安全评价提供参考。     

Simultaneous determination of species-specific isotopic composition of Hg by gas chromatography coupled to multicollector ICPMS

This work presents the simultaneous online determination of the isotopic composition of different Hg species in a single sample by the hyphenation of gas chromatography (GC) with multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS). With the use of commercially available instrumentation, precise and accurate species-specific Hg isotope delta values (per mil deviation of the Hg isotope ratio in the sample relative to a reference standard) have been obtained online from consecutive GC transient signals. The use of isothermal temperature programs to extend the elution of the Hg species, the proper selection of the peak integration window, as well as the preconcentration of real samples are critical to provide optimal counting statistics. Also, isotope ratio drift during transient signal elution was overcome by introducing a mixed Hg(II) and MeHg standard bracketing scheme and expressing all results using the delta-notation relative to SRM NIST-3133. Using the proposed methodology, we have obtained an external 2SD precision of 0.56 per thousand for delta (202)Hg that is more than 10 times smaller than the overall Hg stable isotope variation thus far observed in terrestrial samples. The measurement of species-specific Hg isotopic composition relative to SRM NIST-3133 has been validated versus two other analytical techniques, i.e., conventional nebulization (CN) of Hg(II) solution and cold vapor (CV) generation of Hg (0) vapor. A good agreement between the species-specific delta values obtained by the different techniques has been obtained in secondary fractionated reference standard (UM-Almaden) and environmental matrixes, i.e., BCR-CRM 464 (tuna fish) and IAEA-085 (human hair). The results show mass-dependent and mass-independent fractionation in environmental samples, i.e., mass-independent fractionation of odd isotopes (199)Hg and (201)Hg in tuna fish was observed. This methodology provides new possibilities for the future study of species-specific stable isotope geochemistry of Hg and other trace metals.     

Simultaneous determination of five tobacco-specific nitrosamines in mainstream cigarette smoke by isotope dilution liquid chromatography/electrospray ionization tandem mass spectrometry

Tobacco-specific nitrosamines (TSNAs) have been previously implicated as a source of carcinogenicity in tobacco and cigarette smoke. Accurate quantification of these chemicals is needed to help assess public health risk. We have developed and validated a specific and sensitive method to simultaneously measure five TSNAs in the particulate phase of mainstream tobacco smoke. Cigarette smoke particulate, produced using standardized machine smoking protocols, was collected on a Cambridge filter pad. The particulate matter was extracted using methylene chloride, back extracted into aqueous solution, further purified by solid-phase extraction, and analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry using isotopically labeled analogues as internal standards. Limits of detection for this method ranged from 0.05 to 1.23 ng/mL using an injection volume of 20 microL. A linear calibration range spanning 2.5-2500 ng/mL was adequate to measure TSNA levels in cigarette smoke. The method achieved excellent reproducibility and accuracy. The identity of each TSNA was established by chromatographic retention time, analyte-specific fragmentation patterns, and relative peak area ratios of two product/precursor ion pairs. This new method provides higher sensitivity, specificity, and throughput than earlier methods for TSNA determination.     

Simultaneous determination of thiabendazole and mebendazole in tablets by high-performance liquid chromatography

Reversed-phase high performance liquid chromatography using an RP 18 column (4 × 125 mm), tetrahydrofuran-acetonitrile-0.5% formic acid (5:25:70, v/v/v) as mobile phase and UV detection at 254 nm enabled the simultaneous determination of thiabendazole (TZ) and mebendazole (MZ) in tablets. The method showed linearity over 4.0 to 40.0 μg TZ/ml and 6.0 to 60.0 μg MZ/ml. The correlation coefficient r was .9999 for both TZ and MZ. The coefficient of variation (CV) was 0.59-0.80% for TZ and 0.49-0.67% for MZ. The average recovery was 100.54-101.17% for TZ and 100.35-101.13% for MZ. The excipients of the tablets did not interfere in the proposed method. The developed method is precise, accurate, and selective for the determination of both benzimidazoles analyzed.