随着海上原油产量大幅增加,海上原油贸易随之快速增长,因计量误差引起的原油贸易争议也呈上升趋势.本文结合南部海上原油计量近十年的数据,分析了影响原油计量的流量计、样品密度水分、船舱、底水等因素,为海上石油贸易顺利进行提供依据.

原油的水分、密度等项目是评价原油品质和双方贸易的最主要指标,也是原油计量最主要的参数之一,直接影响到贸易双方的经济效益.本文依据原油检测标准,结合海上原油品质检测实际情况,通过对海上原油取样,进行水分、密度实验室检测,分析出海上原油品质检测中导致结果差异的关键因素,从而进一步提高海上原油贸易计量的精确度,为减少海上原油贸易交接计量纠纷提供借鉴.

本研究收集了4个国家共166组大豆样本,采用X射线荧光光谱技术测定大豆样本中多元素含量,使用箱型图校正法,剔除4组异常样本.对样本数据集进行主成分分析,结果表明,前5个主成分的累积方差贡献率达到99.67％.前5个主成分为输入向量,4个产地作为目标向量,采用支持向量机(SVM)、RUSBoosted树(RUSBoosted Trees)与人工神经网络法(ANN)建立产地鉴别模型.人工神经网络建模鉴别效果最好,整体鉴别准确率可达95.8％,其中阿根廷、巴西和乌拉圭鉴别准确率均为100％,美国鉴别准确率为85.7％.

为了准确、快速地识别大豆产地,通过近红外光谱技术(NIRS)结合主成分分析(PCA)和人工神经网络技术(ANN)研究不同国家大豆内含特征,建立进口大豆产地识别模型.采用箱型图校正法,剔除阿根廷、巴西、乌拉圭、美国等4个国家166组大豆样本中12组异常样本.采用多元散射校正(MSC)、标准正态变量(SNV)、Savitzky-Golay(SG)平滑滤波等方法进行光谱数据预处理,结果表明,采用SG(3)平滑结合MSC预处理效果最好.主成分分析表明,前10个主成分的累积贡献率达到99.966％.选取主成分分析得到前10个主成分为输入向量,4个产地作为目标向量,分别采用支持向量机(SVM)、邻近算法(KNN)与人工神经网络法(ANN)建立识别模型.结果表明,采用BP-ANN建模效果最好,总体测试集准确率为95.65％,其中阿根廷准确率为100％,巴西准确率为100％,乌拉圭准确率为80％,美国准确率为100％,该模型能够实现对进口大豆生产国别的识别.

提出了高温燃烧水解-淋洗液在线发生离子色谱法来测定铬矿石中氟和氯.并通过实验确定了较优的工艺条件:称样量、水解时间、水解温度、氧气流量及离子色谱仪条件,标准曲线线性相关系数大于0.999.实验结果表明氟和氯的3个添加浓度(20、50、100μg/kg)的平均回收率范围为96％～105％,相对标准偏差小于4.30％,检测限可达到20μg/kg.

采用高温水解铁矿石-氢氧化钠溶液吸收装置,建立了高温水解前处理铁矿石样品,离子色谱法同时测定铁矿石中氟和氯的分析方法.样品与水解催化剂V2 O5的质量比为1:1,采用两组氢氧化钠溶液作为吸收剂.系统、 全面地考察了测定方法的影响因素,并确定了水解温度1100℃,水解时间30 min,氧气流量400～500 mL/min为最优高温水解预处理铁矿石;优化离子色谱法条件;方法的线性相关性比较好(r>0.999).

Aiming at the problems in simultaneous determination of major and minor components in chromite ,the simultaneous determination method of 14 major and minor components in chromite (including Cr2 O3 ,Fe ,MgO ,SiO2 ,Al2 O3 ,CaO ,P ,S ,K2 O ,Ni ,Co ,Ti ,Mn and V) by X-ray fluorescence spectrometry with fusion sample preparation was established .Li2 B4 O7-LiBO2 (m : m = 67 : 33) was used as flux with dilution ratio of 1 : 20 .The oxidation-releasing mixture (500 g/L NaNO3 solution-70 g/L LiBr solution) was added quantitatively .The sample was pre-oxidized at 700 ℃ for 5 min and then fused at 1100 ℃ for 20 min .The as-prepared sample piece was transparent .The synthetic calibration sample series were prepared using certified reference materials of chromite , vanadium-titanium-iron concentrate and spectrum pure nickel oxide with different ratios .The content range of calibration curve was expanded .The detection limit of method was 10-748 μg/g .The matrix effect was corrected by theoretical α coefficient method and empirical coefficient method .The precision test was conducted with one chromite sample .The relative standard deviations (RSD , n = 12) of determination results were all less than 5% .The proposed method was applied for the analysis of one certified reference material of chromite ,and the results were consistent with the certified values .The proposed method could meet the detection requirements of components in chromite .

采用粉末压片法制样,建立了X射线荧光光谱法测定石灰石中10种组分(CaO、SiO2、MgO、Fe2O3、Al2O3、MnO、TiO2、K2O、Na2O、SrO)含量的方法.通过试验确定石灰石样品粒度达到74 μm以下,3.00g样品称样量,30 t压力压片的制样条件.试验发现,压片时利用硼酸镶边和硼酸衬底,不另外添加粘结剂可解决样品粘结问题;利用经验α系数法校正基体效应,校正后校准曲线的离散度较小,有效地消除了重叠谱线干扰.各组分的检出限在0.47～188.08 μg/g之间.对石灰石试样进行精密度考察,各组分含量的相对标准偏差(RSD)在0.042％～5.7％范围内;对石灰石标准样品进行分析,各组分的测定值与认定值相符.方法满足进出口商品检验工作对效率和准确度的要求.

A method for the determination of 14 quinolones and sulfonamides medicine resisduces,enrofloxacin,ciprofloxacin,sarafloxacin,difloxacin,flumequine,oxilinic acid,sulfamethoxazole,sulfadiazine,sulfaquinoxaline,sulfamerazine,sulfamethazine,sulfamonomethoxine,sulfadimethoxine,trimethoprim in aquatic product was developed by using high performance liquid chromatography-electrospray ionization tandem mass spectrometry(HPLC-ESI MS/MS).After homogenization,samples were extracted with 1% acetic acid-acetonitrile.The extracts were cleaned by hexyl hydride.Identification and detection were achieved by electrospray ionization(ESI) in positive mode using multiple reaction monitoring of liquid chromatography coupled with tandem mass spectrometry.The linearity of all the 14 quinolones and sulfonamides medicine in the range from 0 to 100 μg/kg is correlation coefficient greater than 0.99.Antibiotics are quantified by external standard method.Recoveries are within 70.0%~110.0% at the spiked level of 5 to 50 μg/kg.The relative standard deviations(RSDs) for the 14 quinolones and sulfonamides medicine are less than 12%.The detection limits were 0.1 to 0.5 μg/kg.

A method was developed for the determination of 17 phthalic acid esters in fatty food by dispersive solid phase extraction-gas chromatography-mass spectrometry (d-SPE-GC-MS). Tea milk samples were extracted with acetonitrile: methyl tert-butyl ether (9:1, V/V), and the extract was cleaned up by MAS-PAEC d-SPE column. Flavor seasonings samples were extracted with acetonitrile (saturated with hexane): methyl tert-butyl ether (19:1, V/V), and the extract was cleaned up by CNW d-SPE column. Matrix-match external standard method was used for quantification. The results showed that the average recoveries of 17 phthalic acid esters in milk tea were 82.2%-125.4% and relative standard deviations were less than 16.5%. The limit of detection (LOD) of all the compounds were 100-200 mu g/kg. The average recoveries of 17 phthalic acid esters in flavor seasonings were 70.9%-115.5% and relative standard deviations were less than 9.8%. The limits of detection (LOD) of all the compounds were 400-800 mu g/kg. The method is quick, sensitive, easy, cheap, rugged, and can be applied to the detection of 17 phthalic acid esters in fatty food.

In order to fast and accurate test of five tetracycline antibiotics (TCs) residues in aquatic food product {Tetracycline (TC), Oxytetracycline (OTC), and Chlortetracyline (CTC)}, a high performance liquid-MS/MS detection method was developed. Results showed that the average recoveries of the Tetracycline at the three concentrations of (20, 50 and 100) ug/kg were from 84% to 112% with relative standard deviation less than 18.3%. The detection limits of the TCs were 20ug/kg. For its high sensitivity, stability, the fast and easy pre-treatment and the reducing test costs, this method can be used for determination of tetracycline antibiotics residues in aquatic products.

A method for direct determination of Cu, Pb, Zn, S, Mg and As in copper sulphide concentrates by Axios PW4400 wavelength dispersive X-ray fluorescence spectrometer using lithium metaborate-lithium tetraborate fusion sample preparation method has been developed. Some parameters affecting the sample preparation such as flux, glassing reagent and pre-oxidation condition were studied. The matrix effect was corrected by combination of the theoretical alpha coefficients and experienced coefficients. The precision of the method is better than 3.0%RSD( n=12).

A mathematical model for evaluation of the uncertainty of high performance liquid-ms/ms in measuring the residue of Sulfadiazine in tilapia was established by termwise analyzing and synthesizing the sources of uncertain in determination.And the uncertainty for detection of Sulfadiazine in tilapia by HPLC-MS/MS was obtained.

The content values of poisonous and harmful elements among imported laterite nickel ores were analyzed.The results showed that the content values of Hg,Pb and Zn were acceptable,while the content values of Cr,Cd and As in some batches were rather high,indicating to the risk of pollution on the environment to some extent.Especially,the content values of Cd and As were rather high at the same time,indicating to a higher risk of pollution to the environment.Therefore more attention should be paid and some more strict control managements should be taken.

An inductively coupled plasma atomic emission spectrometry(ICP-AES) was used for the determination of Cd,Cr,Cu,Pb,Sn,Bi,Co and Zn in the nickel ores.The sample was dissolved in hydrochloric,with hydrofluoric acid as flux.In order to eliminate hydrofluoric acid,perchloric acid was added and heated to evolve fumes of perchloric acid After dissolving the salts with hydrochloric,Cd,Cr,Cu,Pb,Sn,Bi,Co and Zn were determined by ICP-AES in measuring conditions selected.The scope of determination was 0.002%～0.3% for each element.The rates of recovery were 96.90%～101.35%.The relative standard deviations lay between 0.34% and 1.78%.