氢化物发生-原子荧光光度法测定食品添加剂氢氧化钠中的汞

目的:探讨应用氢化物发生-原子荧光光度法测定食品添加剂中汞的含量.方法:样品被酸中和后.在一定酸度下,用溴将汞转化为二价汞,在最佳的实验条件下,直接用AFS2201原子荧光光度计进行测定.结果:该法在0-5.0μg/L线性范围内,回归方程为:Y=98.87X-3.29,相关系数为r=0.9999,方法的检出限为0.15 ng/ml,样品加标回收率为90.7%～100.4%,RSD为1.88%～3.31%.结论:本法具有操作简单,灵敏度高,重现性好等优点,适合大批样品的分析检测.     

测汞仪直接测定并评价鲫鱼组织中汞含量

目的:建立用测汞仪直接测定并评价南京地区超市和农贸市场所售鲫鱼组织中的汞含量。方法:用直接测汞仪,分别测定鱼皮、鱼脑、鱼肉及鱼籽组织中的汞含量。结果:鲫鱼组织中的汞含量呈如下规律:鱼脑>鱼皮>鱼肉>鱼籽;鱼龄越大,体内富集的汞越多。对汞含量在0.12 ng～20.00 ng范围内呈线性关系,相关系数r=0.9999,最低检出限为0.04 ng。样品加标回收率为95.8%～104.4%,RSD为1.63%～2.92%。本方法与国标法无显著性差异。结论:本方法精密度和准确度较好,测汞时无需进行样品前处理,具有取样量少,简单、准确和高效等特点,能满足样品检测的要求。     

湿法消解--原子荧光光谱法测食品中汞的研究

汞是食品特别是保健食品卫生检验常测指标,汞的毒性很高,而食品中汞的含量一般极低,加上汞在前处理过程中极易挥发损失,给准确测定带来一定难度.氢化物发生(HG)与原子荧光光谱法(AFS)联用,是我国近年发展较快的一种痕量分析技术,与国标方法相比,AFS法具有方法灵敏度高,精密度好和操作快速简便等优点.本文提出中低温湿法消解、空气冷凝大批量消解样品,氢化物--原子荧光光谱法测定各类食品中汞含量的分析方法[1,2].方法检出限为0.02ng/ml,线性范围为0～20ng/ml,回收率为94.3%～102.3%.     

直接测汞仪快速测定食品中的总汞

利用DMA-80直接测汞仪,建立食品中总汞的快速测定方法。食品置于样品舟中,无需前处理直接测定其总汞含量。结果表明,本法在0~100 ng范围内呈良好线性关系,加标回收率为96.3%~108.6%,精密度为3.32%,检出限为0.4μg/kg。分析菠菜和圆白菜标准物质,检测结果准确可靠。本法检出限低,回收率高,精密度好,操作简便,适用于食品中总汞含量的准确快速测定。     

食品中汞的热分解齐化原子吸收测定法

目的使用直接测汞仪,建立测定食品中汞含量的新方法。方法采用热分解齐化原子吸收法,直接测定食品中汞的含量。结果回归方程为A=0.043 0 Hg+0.0160相关系数为R=0.999 5,线性范围为0.00～10.00 ng,精密度为0.62%～17.2%,回收率为85.8%～105.8%,检出限为0.03 ngHg。结论该方法操作简便快速,各项指标均可满足食品中汞的测定要求。     

氢化物发生-原子荧光光度法测定保健食品袋泡茶中的总砷

目的:本文建立了保健食品袋泡茶中总砷的测定方法并测定了20种保健食品袋泡茶中总砷含量。方法:以微波消解和湿消解法处理样品,原子荧光光度法进行测定。结果:本文测定总砷的线性范围为0μg/L～80μg/L,相关系数为0.9994,方法回收率为92.4%～109.6%,RSD为2.5%。测定的20种保健食品袋泡茶中总砷含量为0.10 mg/kg～0.80 mg/kg。结论:实验表明,本法简单、快速、准确,可以用于保健食品袋泡茶中总砷含量的测定。     

保健食品中铅、砷、汞微波消解前处理方法的研究

目的 应用微波消解前处理测定保健食品中铅、砷、汞的含量。方法 用微波溶样系统对保健食品进行消解，消解过的样品可用于石墨炉的原子吸收光谱仪和原子荧光光谱仪同时测定保健食品中的铅、砷、汞的含量。结果 本方法测定铅、砷、汞的检出限分别0．28μg／kg、0．007mg／kg和0．10μg/kg；回收率分别为88．5％～106．0％、85．0％～106．0％、和88．2％～96．7％；测定线性范围分别为0～100．0 ng／ml、0～200．0,ng／ml和0～60．0μg／L。结论 该方法简便、快速，灵敏度、精密度、准确度较好，适合保健食品的快速消解及微量金属污染物的定量分析。     

尿中汞的热分解齐化原子吸收法

目的直接使用测汞仪,建立测定尿汞含量的新方法。方法采用热分解齐化法原子吸收法,直接测定尿中汞的含量。结果回归方程:A=0.046 62C;相关系数:R=0.999 9;线性范围0.20～12.5 ng;精密度1.2%～6.5%;样品加标回收率为92.8%;对尿汞标准物质测定9次,平均值为(32.0±0.8)μg/L,结果均在证书给出的不确定度范围内;对实际样品测定,进样量0.1 ml时,其结果均0.46μg/L。结论该方法操作简便快速,各项指标可满足尿汞的测定。     

直接测汞法在各类型食品分析中的应用研究

目的：使用直接测汞仪测定食品汞,掌握不同种类食品的测定条件。方法：将各种食品置于镍或石英样品舟中,在100℃～300℃进行干燥及预炭化,800℃～950℃灰化,汞经金齐化管富集,样品分解完成后瞬间加热破坏汞齐,汞蒸气进入比色池,直接测定样品中汞的含量,分析操作采用仪器全程控制。通过分析标准样品来考察方法准确性、精密度及适用性。结果：两种标准物质的汞测定值均在给定值范围内,CV分别为3.2%和5.4%。连续4个月采用直接测定法检测某固体胶囊型保健食品,测定结果均值8.47～8.56μg/kg（n=6）,CV为2.2%～3.9%（n=6）。结论：该方法准确度和精密度高,检测限可达0.01 ng。与国家标准方法（GB/T5990.17-2003）比较,解决了样品前处理过程中的损失问题,大幅缩短了食品中汞的分析周期,在食物中毒等公共卫生突发事件的检测中具有良好的应用前景。     

冷原子吸收光谱法测定保健食品中汞的消解方法的改进

[目的]改进保健食品中汞测定的消解方法。[方法]采用五氧化二钒法对 20 份保健品进行前处理实验。[结果]本法线性范围为0~4 ng/ml,检出限为0 25 ng/ml。RSD在0 2%~1 3%之间,回收率在98 8%~101 7%之间,和国标法比较差异无统计学意义。[结论]实验证明用本法进行样品前处理效果良好,大大提高了工作效率,可推广使用。     

PCR系统制备地高辛标记的探针检测脊髓灰质炎病毒核酸

笔者应用聚合酶链反应（PCR）合成系统，以逆转录的SabinⅠ、Ⅱ、Ⅲ型病毒cDNA为模板，在反应液中加入标记的Dig-dUTP，经扩增制备了地高辛配基标记的脊髓灰质炎病毒cDNA探针、该法比PCR扩增产物后，电泳，片段回收到标记、提纯，常需3天。结果比较PCR技术直接制备地高辛标记cDNA探针方便，快速，标记率高，用于型别鉴定比中和试验快，敏感，特异性强等优点。     

Dental Services Utilization by Women of Childbearing Age by Socioeconomic Status

For women of childbearing age, oral health not only affects their physical and psychological well-being but also that of their children. This study used the 2003–2004 Ohio Family Health Survey (N = 9,819) to examine dental need and utilization by women in Ohio. Predisposing, enabling, and need variables were examined as they effect dental health service utilization by women of childbearing age at different socioeconomic status (SES) levels. The proportion of women in the low SES group self reporting a dental need (18%) was 3 times that of the proportion of women in the higher SES group with a self reported need (6%). Results of bivariate analysis showed that having a dental visit in the past year varied significantly by SES, race, insurance status, provider density, and need. A racial disparity in dental service utilization was noted in the bivariate analysis of the middle SES group. While dental need and type of dental coverage varied by SES, both were significantly associated with utilization of dental services within all 3 SES categories in the logistic regressions. These results suggest that measures need to be implemented to meet the goal of increasing access and utilization of dental health services by low-income populations.     

Reversal by ascorbic acid of suppression by endogenous histamine of rat lymphocyte blastogenesis

Addition of concanavalin A (Con A) to a culture of spleen cells of ODS-od/od rats, which cannot synthesize ascorbic acid, increased the activity of histidine decarboxylase (HDC) in the culture, leading to accumulation of histamine (Hm) in the medium. Treatment of the culture with cimetidine, a type 2 Hm antagonist, enhanced Con A-dependent lymphocyte blastogenesis even in the absence of any exogenously added Hm. Addition of low doses of histaminase increased Con A-dependent lymphocyte transformation. At higher doses, it abrogated the reaction. At concentrations of more than 10(-10) M, exogenously added Hm suppressed the Con A-dependent uptake of [3H]thymidine by the lymphocytes, but it significantly augmented the response at 10(-14) M. The addition of ascorbic acid (10(-8)-10(-5) M) to the culture suppressed the Con A-mediated HDC induction and inhibited Hm biosynthesis. Concomitantly added ascorbic acid at the concentrations of 10(-8)-10(-4) M increased the uptake of [3H]thymidine dependent on Con A or phytohemagglutinin by the lymphocytes. These results suggest that mitogen-dependent lymphocyte blastogenesis is activated by Hm produced by the spleen cells per se. However, when culture was prolonged, high concentrations of Hm suppressed the reaction. Ascorbic acid enhances mitogen-dependent lymphocyte blastogenesis through inhibition of HDC induction, leading to attenuation of immunosuppressive Hm production by the spleen cells.