氢化物发生-原子荧光法测定轻质油中的砷

采用H2SO4-H2O2萃取轻质油样品,以盐酸为载液,硼氢化钾为还原剂,通过氢化物发生-原子荧光法测定轻质油中的砷含量。结果表明,用该方法测定轻质油中砷含量的检出限为0.12μg/L,相对标准偏差小于3%,加标回收率为98.6%~101.3%。该方法灵敏度高,测定结果准确可靠,可广泛应用于轻质油样品中砷含量的测定。     

电位滴定法测定原油酸值

从测定酸值用的滴定溶剂中筛选出能够快速溶解原油(特别是稠油)的溶剂,考察了原油中的水与无机盐对电位滴定法测定原油酸值的影响。结果表明,甲苯/异丙醇/四氢呋喃/水混合溶剂(体积比=50.0:24.5:25.0:0.5)能快速溶解稠油,在电位滴定法中用该滴定溶剂测定原油酸值准确、快速。对滴定曲线有明显突跃的原油。原油中水与无机盐对原油酸值测定结果没有影响。对滴定曲线没有明显突跃的原油,当水含量≤5％或无机盐含量≤100μg/g时,对测定结果影响很小;但水含量>5％或无机盐含量>100μg/g时,原油酸值随水含量或无机盐含量的增加而增加。     

微波消解/ICP-AES法测定拟薄水铝石中的微量Na和S元素

建立了同时测定工业拟薄水铝石中Na含量和S含量的微波消解-电感耦合等离子体发射光谱(ICP-AES)分析方法,考察了微波消解条件、元素间干扰对测定结果的影响,建立了测定Na、S含量的标准曲线。优化的微波消解条件为：样品0.1 g,消解液(盐酸)10 mL,消解温度185℃,消解时间50 min。所建ICP-AES方法测定溶液的Na质量分数为0.07～15.00μg/g,测定结果拟合线性相关系数为1.000 00,相对标准偏差为1.1%,加标回收率为100.0%～101.0%;测定溶液的S质量分数为0.10～35.00μg/g,测定结果拟合线性相关系数为0.999 99,相对标准偏差为1.1%,加标回收率为95.0%～100.0%。该方法适用于Na质量分数为35～7 500μg/g、S质量分数为50～17 500μg/g的工业拟薄水铝石的Na、S含量测定。     

裂解气脱砷催化剂及工艺研究

采用浸渍法制备以复合型的银化合物为活性组分的脱砷剂,用于裂解气及C3馏分等液态轻质烃中砷化物的脱除。考察了脱砷剂分别应用于裂解气和液态轻质烃脱砷时原料砷含量及其空速对脱砷活性的影响。在适宜的操作条件下,脱砷剂能将原料中1000～5000μg/kg的砷脱除至10μg/kg以下。脱砷剂质量容砷量大于4%(砷相对于脱砷剂的质量分数)。     

工业硫磺产品检测新技术

硫磺是一种用途广泛的重要化工原料,其产品质量依据GB/T 2449.1-2014《工业硫磺 第1部分:固体产品》和GB/T 2449.2-2015《工业硫磺 第2部分:液体产品》指标和检测方法进行判别。针对工业硫磺标准中检测方法的局限性,建立了光谱法测定砷含量、铁含量、硫化氢和多硫化氢含量等新方法。结果表明:原子荧光光谱法测定硫磺中砷含量,方法检出限0.005 μg/g、加标回收率94%~103%、与GB/T 2449.1-2014的比对偏差<0.16 μg/g;原子吸收光谱法测定硫磺中铁含量,方法检出限0.1 μg/g、加标回收率91%~109%、与GB/T 2449.1-2014的比对偏差<1 μg/g;红外光谱法测定硫化氢和多硫化氢含量,方法检出限5 μg/g、测量范围5~500 μg/g、重复性<8%;建立的方法满足检测要求。同时也探讨了光谱法测定砷含量、铁含量、硫化氢和多硫化氢含量制定成国家、行业或企业标准的可行性和适用性。     

高灵敏度X射线荧光光谱仪对汽油中硅含量的快速测定

建立利用高灵敏度能量色散X射线荧光光谱仪快速测定轻质燃油中硅含量的方法,并进行准确性和重复性考察。结果表明:该测定方法在硅质量分数为0～100μg/g范围内的定量标准曲线具有良好的线性关系,R~2大于0.999 9;方法检出限为1μg/g,样品回收率为95.7%～103.0%,相对标准偏差小于5.79%,可用于汽油中硅含量的测定。     

原油有机氯转移剂的制备与效果评价

以合成的三乙基苄基氢氧化铵为相转移催化剂,与乙醇钠、溶剂复配后制得一种原油有机氯转移剂,在原油电脱盐、脱水条件下将原油中的有机氯转化为无机氯而将其脱除,减少氯对后续工序的危害。在实验室分别对四种原油进行了脱有机氯的效果评价,结果表明:随着加剂量的增加,有机氯的脱除率增加。当加剂量为20～40μg/g时,原油中有机氯质量分数可降低到3μg/g以下。该有机氯转移剂在500 Mt/a的常减压蒸馏装置上进行了工业试验,结果表明:加剂量为10μg/g时,电脱盐罐排水中氯离子含量增加,常顶及初顶冷凝水中氯离子质量分数分别减少69.71%和18.92%,脱除有机氯的效果比较明显。该原油有机氯转移剂无毒无害,加注方便,加剂费用低,不影响装置的正常生产。     

HF-101原油脱钙剂的工业应用研究

采用大港油田集团油田化学有限公司研制的HF-101脱钙剂对中国石油锦州石化分公司炼油厂掺炼的杜巴原油脱钙效果进行了实验室评价及工业试验。实验室评价结果表明,在剂钙质量比为2:1、注水量为5%、电脱盐温度130℃、破乳剂加量30μg/g的条件下,原油脱钙率达到90.89%～91.43%,显示了良好的脱钙效果。工业应用试验结果表明,使用HF-101脱钙剂后原油中的钙平均脱除率可达到90.89%,脱后原油的平均钙含量为24.81μg/g;原油的灰分由脱钙前的0.065%降至0.030%左右;原油的盐含量和含水量也大幅度下降。并且使用HF-101脱钙剂可使电脱盐装置的操作电流下降50%,具有较好的节能降耗作用。     

亚甲蓝法在测定原油硫化氢含量中的应用

将硫化氢用不含氧的氮气从已知量的原油中吹出,用醋酸锌溶液吸收,随后在有氯化铁存在的强酸性溶液中与N,N-二甲基-1,4苯二胺反应生成亚甲蓝,用分光光度计测定亚甲蓝含量,计算得到硫化氢含量。该方法的RSD为1.3%,原油中硫化氢的加标回收率为90%?110%,检出限为0.042 μg/g。适用于原油及馏分油中硫化氢含量的测定。     

原油中有机氯化物的转移脱出技术研究

随着油田二采、三采原油的劣质化,原油中的有机氯化物含量逐渐增大,由于电脱盐只能脱除无机氯离子,对于有机氯化物则无能为力,而原油中的有机氯化物在蒸馏过程中,在高温与水蒸气的共同作用下水解出氯离子,生成腐蚀性极强的氯化氢,对设备造成了严重的腐蚀,同时极易引起后续装置催化剂的中毒。在借鉴了现有其它领域有机氯化物脱除方法的基础上,根据原油的特点和适用条件,对向原油中加入氯转移剂的脱氯方法进行了研究。研究表明,这种脱氯工艺操作简单,通过电脱盐装置即能脱出80%以上的有机氯,当加入10μg/g的脱氯剂时,原油中有机氯减少2μg/g,当氯转移剂加入量为50μg/g时原油中的有机氯几乎全部转移脱除,蒸馏塔顶中Cl-含量可大幅降低,说明这种脱氯工艺有比较好的脱氯效果。     

采用二乙氨基二硫代甲酸银光度法测定裂解气中的砷含量

建立了裂解气中痕量砷(As)的二乙氨基二硫代甲酸银光度测定法。该方法适用于As质量浓度为mg/L级的裂解气的测定。在H2SO4加入量为20 mL,10～20目的锌粒加入量为6 g,吸光波长为530 nm的优化条件下,As含量测定结果的相对标准偏差小于10%,方法的回收率为95%～105%。     

Inorganic arsenic in rice and rice-based diets: Health risk assessment

Total and inorganic arsenic (As) content in rice and rice-based diets (n = 59) obtained from supermarkets in South Australia were studied to investigate the contamination levels and whether consumption of these products pose potential health risks to young children and adults. Results show that of the 59 rice-based products, 31 (53%) exceeded the EU recommended value (100 μg/kg) of As for young children and 13 (22%) samples had higher than maximum level of 200 μg/kg recommended for adults. Arsenic content varies as rice crackers > baby rice > rice cakes > puffed rice > other rice-based snacks > ready-to-eat rice. Of the 6 categories of rice-based products, except ready-to-eat rice, all others exceeded the EU recommended value for young children. Even manufacture recommended servings deliver significant amounts (0.56–6.87 μg) of inorganic As. These amounts are within the range of BMDL₀₁ values indicated by the European Food Safety Authority (EFSA), which means the risk cannot be avoided for young children and adults considering the levels of total and inorganic As in rice-based products.     

用气相色谱法测定高密度聚乙烯中爽滑剂芥酸酰胺的含量

以异丁醇为萃取剂,使用氢火焰离子化检测器,采用外标法定量,萃取液经SE-30型毛细管柱(15 m×0.32 mm×0.5μm)分离,建立了用气相色谱法测定高密度聚乙烯中爽滑剂芥酸酰胺含量的分析方法。结果表明,芥酸酰胺在280℃气化后可直接测定,在2.5～100.0μg/g范围内线性关系良好(相关系数(r)为0.999 8,样本数(n)为7),加标回收率为96%～105%,相对标准偏差(RSD)不大于5%,检出限为0.96μg/g。     

氢氧燃烧－分光光度法测定气态烃中的痕量砷

提出一种氢氧燃烧仪与分光光度计联用测定气态烃中痕量砷的方法。考察了方法的最佳条件、精密度和准确性，并对现场样品进行分析。结果表明，该方法干扰少，操作简单，分析速度快，检测限低至１×１０￣（－９）。对丙烯样品的７次平行分析，相对标准偏差为４．６１％，回收率为９６．６％。     

Determination of ethyl carbamate in cider spirits by HPLC-FLD

An analytical method based on HPLC-FLD with prior derivatization with 9-xanthydrol for the determination of ethyl carbamate (EC) in cider spirits is reported. The parameters usually examined in the method validation were evaluated. Good linearity was obtained with a correlation coefficient exceeding 0.9999, the limits of detection and quantitation being 1.64 and 3.56 μg/L, respectively. Recoveries ranged between 94% and 98%, while the precision of the method was <5% (RSD). The method was used to determine EC in samples from different origins with the aim of completing the characterization of cider spirits. Values obtained were usual for this type of drink, ranging between the lower limit of quantitation and 67 μg/L.     

Development and validation of an analytical method for the determination of arsenic,cadmium and lead content in powdered infant formula by means of quadrupole Inductively Coupled Plasma Mass Spectrometry

Cadmium (Cd), lead (Pb) and arsenic (As) can enter the food chain through the environment and/or as a consequence of the manufacturing process making foodstuffs the main human exposure route to these chemical elements. The risk associated with this exposure is of such a big concern for human health that the European Food Safety Agency recommends to reduce the exposure to Cd and Pb so as to protect especially vulnerable subgroups of population (e.g., infants). Therefore, the setting of new maximum levels (MLs) for chemical elements in infant formulae (e.g., for Cd) or the reconsideration of the existing ML for Pb is under discussion. On this basis, the availability of analytical methods, precise, accurate and sensitive enough to quantify low concentration values, is a key point especially for official control laboratories that have to state the sample compliance using a fully validated method with an associated uncertainty compliant with the requirements specified in the pertinent regulations. This work describes the development and validation of an analytical method to quantify As, Cd and Pb in powdered infant formulae based on animal protein at values of concentration close to the MLs that are likely to be set. The results obtained make the method suitable for a precise and accurate determination of these chemical elements at these low concentration values. In particular, the results for limit of quantification (LoQ) were respectively (μg kg⁻¹): As 6.2, Cd 1.2 and Pb 4.5. While for the recovery rates the following percentages were obtained: As 105%, Cd 98% and Pb 108%. The expanded uncertainties were found extremely satisfactory (Cd 13% and Pb 19%). The LoQ and the uncertainty for Pb meet the requirements set in Commission Regulation (EC) No. 333/2007 and following amendments being lower than the maximum values allowed. Even for Cd the expanded uncertainty resulted adequate in relation with the low concentration considered.     

Detection of egg and milk residues on working surfaces by ELISA and lateral flow immunoassay tests

In the last few years awareness for allergen management has increased among operators in the food chain. Since a small quantity of allergenic food can trigger an allergic reaction, accurate information in food product labels is essential for people who suffer from food allergy. A key point to reduce the risk of uncontrolled allergen contamination is to implement a strict and validated cleaning process. In this work a sampling method based on swabbing has been optimized with two analytical methods (ELISA and lateral flow tests) for milk and egg analysis on surfaces. Swab material, extraction buffer composition, temperature, time for recovery and the quantity of the allergen residue on the surfaces have been evaluated and a specific procedure was proposed. The new method has demonstrated a good performance to recover egg or milk proteins from two typical working surfaces (stainless steel or Formica). Egg and milk powder were detected by ELISA at a level as low as 0.04 and 0.2 μg, respectively. However, the detection level with lateral flow tests rose to 0.07 μg for egg powder and 0.6 μg for milk, depending on the kind of surface. On average, repeatability of swabbing method ranged from 18 to 32%. Both methods could be applied for validation the cleaning processes and for a routine verification after cleaning.     

石墨炉原子吸收测定水处理剂聚合硫酸铁中镉

利用石墨炉原子吸收法测定不同批次的水处理剂聚合硫酸铁中痕量镉的含量。镉在0.2μg/L～1.2μg/L范围内具有较好的线性关系,测试结果相对标准偏差为1.2%,回收率在95.0%～101.0%,测试具有较好的精密度和回收率,具有一定的实用价值。     

催化分光光度法测定重油中的微量钴

在氨水介质中，Ｃｏ（Ⅱ）能催化二苯偶氮碳酰肼被溶解氧氧化而褪色。本文进一步考察了此方法的测定条件及二氨替吡啉甲烷萃取Ｃｏ（Ⅱ）的回收率，并应用该法成功地测定了原油及润滑油中的钴。钴的回收率９３．０％─９９．３％，摩尔吸收系数１．１×１０６Ｌ·ｍｏｌ（－１）·ｃｍ（－１），线性范围０．０５─０．４μｇ／２６ｍｌ，检测限０．０８μｇ／２６ｍｌ，相对标准偏差２．２％─４．４％。方法准确、灵敏、易行。