火焰原子吸收法测定尿锰探讨

采用火焰原子吸收法测定尿锰,该方法的线性范围为0～200ng／ml,检出限3．5ng／ml,回收率97．8％～104．5％,批内、批间RSD〈10％。本法尿样处理简单,分析速度快,适用于重点人群普查、职业中毒初筛。     

火焰原子吸收光谱法测铅灵敏线的选择

[目的]扩大卫生检测中火焰原子吸收光谱法检测铅的范围。[方法]选择铅的灵敏线217．0mm和氖灯背景校正，用火焰原子吸收法测定样品中铅的含量。[结果]采用标准曲线法进行计算，该方法的回收率为97．5％～104％，RSD（n=11）为0．42％。[结论]方法简单、快速，结果准确、可靠，测定结果与国标法一致，并可以扩大火焰原子吸收光谱法的应用范围。     

微波消解-石墨炉原子吸收法测定餐巾纸和面巾纸中的铅镉含量

本文建立了用微波消解法消化样品，石墨炉原子吸收法测定其中铅、镉含量的方法。方法检出限为铅3．82ng／ml、镉0．74ng／ml，相对标准偏差均小于5％，回收率在95％～102％，并应用本方法检测了12个样品，取得了良好的效果。     

进出口食品中微量铜的测定

[目的]建立一种简便、准确、实用测定食品中微量铜的方法。[方法]按照火焰原子化法(GB／TS009．13-1996)，样品经炭化、灰化、酸浸制成供试样，导入火焰原子吸收池测定。[结果]该法背景吸收低、稳定、灵敏、方法检出限2．9ng／ml，标准曲线最佳线性范围0-1．99μg/ml，线性相关系数0．9999．RSD5％，平均标样回收98％～112％。[结论]方法快捷、准确、简便、实用。     

原子荧光光度法测定空气中的汞

目的建立原子荧光光度法测定空气中的汞。方法采用高锰酸钾溶液吸收、富集、氧化汞，用原子荧光光度法测定空气中的汞。结果测定0～10．0ng／ml的标准系列6次，r=0．9996，线性范围0～30．0ng／ml，方法最低检出限为0．02ng／ml，回收率90．0％～98．0％，RSD为2．3％-4．5％。采用原子荧光法与原子吸收法（测汞仪）测定结果经统计学分析，t=0．14，P〉0．05，表明无统计学意义。结论本方法具有操作简单、快速，结果准确，灵敏度高，基体干扰少，节省试剂等特点。     

微波消解-原子吸收法测定全血中铁锌钙镁铜铅镉

目的：探索出一种快速检测全血中铁、锌、钙、镁、铜、铅和镉微量元素的方法。方法：微波消解血样，用火焰原子吸收法测定铁、锌、钙、镁和铜，石墨炉原子吸收法测定铅和镉。结果：方法的最低检测浓度分别为5．00、0．10、3．50、0．30、0．05μg／ml，5．00和0．50ng／ml。加标回收率分别为93．5％～96．0％，100．0％-105．0％，94．0％～99．0％，98．0％～99．0％，100．5％～103．0％，96．0％～102．0％和100．0％～110．0％。RSD分别为4．30％～5．24％，0．86％～1．35％。5．58％～7．14％，2．59％～3．09％，0．86％～1．04％，4．33％～7．52％和2．56％～4．77％。结论：测定方法结果满意。     

空气中氯化汞的AFS-230E原子荧光测定法

目的建立车间空气中氯化汞的氢化物原子荧光光度测定法。方法采用稀硫酸溶液吸收、富集，氢化物原子荧光光度法测定车间空气中的氯化汞。结果该方法测定0～10．0ng／ml的标准系列6次，平均相关系数为0．9996，线性范围0～30ng／ml，线性方程Y=2221．4865X-30．2514，方法最低检出限为0．02ng／ml。对不同含量样品加标测定，回收率在90％～95％。对不同含量样品精密度测定，相对标准偏差为2．3％～3．8％。原子荧光法与原子吸收法（测汞仪）测定结果，根据t检验表明2种方法差异无统计学意义（t=0．17，P〉0．05）。结论该方法具有操作简单、快速、结果准确、灵敏度高、基体干扰少、节省试剂等优点。     

火焰原子吸收法测定尿中锰

[目的]寻求一种灵敏度高、准确性好的测定尿中锰的方法。[方法]采用(1 9)高氯酸-硝酸混合酸消化，消化后用(1 99)盐酸溶解残渣，用火焰原子吸收法测定尿中锰。[结果]火焰原子吸收法测定尿中锰的标准差不超过1.96μg／L；RSD不超过2．80％；样品加标回收率为97．0％～02．0％；方法检出限为4．3μg／L。[结论]采用火焰原子吸收法测定尿中锰，其方法灵敏度高、准确度和精密度均符合微量分析要求。     

共沉淀-石墨炉原子吸收光谱法测定高盐食品中的铅和镉

目的：建立一种石墨炉原子吸收光谱法测定高盐食品中的铅和镉的实验方法。方法：采用氢氧化镁共沉淀法捕集铅和镉，使铅、镉离子与干扰组分分离，通过优化实验条件，选择最佳石墨炉工作条件，对高盐食品中的铅和镉进行测定。结果：铅在0～80ng／ml范围内线性关系良好，r=0．9993；镉在0～8ng／ml范围内线性关系良好，r=0．9991。样品加标回收率铅为94％～104％，镉为92％～105％。方法的检出限铅为1．8ng／ml，镉为0．15ng／ml。相对标准偏差铅为3．16％～4．15％，镉为2．90％～4．20％。结论：该法能显著降低高盐食品中氯化钠的基体干扰，具有良好的精密度和准确度。     

石墨炉原子吸收法测定土壤中的铅和镉含量

目的探讨用石墨炉原子吸收法测定土壤中的铅和镉含量。方法采用盐酸-硝酸-氢氟酸-高氯酸混合酸消解技术对样品进行消解，用石墨炉原子吸收法测定铅和镉。结果铅在0～80ng／mL，镉在0～5ng／mL范围内呈良好线性关系，铅相关系数r=0．9981～0．9996，回收率90．5％～104．0％，RSD〈5％，最低检出限为0．02mg／kg；镉相关系数r=0．9990～0．9997，回收率90．5％～105．8％，RSD〈3％，最低检出限0．005mg／kg。结论该方法测定土壤中铅和镉能满足分析要求。     

中华猕猴桃的防癌作用——一、中华猕猴桃汁阻断N-亚硝基吗啉合成

我国特产中华猕猴桃汁在模拟胃液的条件下,能阻断N-亚硝基吗啉的形成。在37℃,pH3.13-3.28,吗啉及亚硝酸钠浓度各为2.0mM,经0.5、1.0及2.0小时,其阻断率分别为98.54％,96.43％及97.99％;此结果优于柠檬汁,后者阻断率分别为84.55％,34.79％及37.43％;并优于含同样量的抗坏血酸溶液,其结果分别为97.56％、89.48％及65.62％。将猕猴桃汁中抗坏血酸经酶氧化后,不同时间阻断率仍分别高达90.24％、88.47％及79.84％;氧化后的柠檬汁阻断率分别为65.04％、10.13％及50.58％。抗坏血酸溶液氧化后,保温2小时的阻断率为22.08％。 用高压液相色谱测猕猴桃浓缩计中还原型抗坏血酸,其量为264mg/100ml,柠檬汁中含量为37.0mm/100ml,其范围分别为215.4至384.6mg/100ml及21.2至67.5mg/100ml。     

Effect of orange juice, folic acid, and oral contraceptives on serum folate in women taking a folate-restricted diet

The effect of folate intake from orange juice on serum folate was evaluated in 60 women (age 20-39) during 9 weeks of a folate-restricted diet. Twenty-one were users of oral contraceptives (OCA). Folate intake from the restricted diet was 159 +/- 5 micrograms/day, as assessed by dietary surveys. Serum folate of women taking OCA was lower than in nonusers at the inception of the study (P less than 0.01). During the initial 2 weeks of restricted diet, serum folates decreased significantly (13.8 +/- 1.8 to 8.5 +/- 0.4 ng/ml; P less than 0.002). This decrease was further prevented by supplementation of the diet for 7 weeks with 100 micrograms/day of total folate from reconstituted frozen orange juice or synthetic folic acid (PteGlu). Both folate supplements were effective (P less than 0.05) in increasing serum folate (9.4 +/- 1.0 to 14.5 +/- 1.4 ng/ml, orange juice; 8.4 +/- 0.7 to 20.5 +/- 5.8 ng/ml, folic acid). Serum folates were similar in women taking either orange juice or folic acid. Serum folate of nonsupplemented women decreased from 10.2 +/- 0.8 to 8.3 +/- 0.4 ng/ml (P less than 0.05). No difference between serum folates of OCA users and nonusers was detected during the restricted diet or folate supplementation. These data indicate that folate in reconstituted orange juice was as available as folic acid, and that utilization of both folate forms and folate in a mixed diet was unaffected by oral contraceptives.     

淋洗液在线发生离子色谱法同时测定果汁中的乳酸、富马酸和柠檬酸

目的 建立离子色谱法同时测定果汁中乳酸、富马酸和柠檬酸的分析方法。方法 样品经Ion PAC AS19 型分析柱（250 mm×4 mm）分离,流速为1.00 ml/min,以氢氧化钾溶液梯度淋洗,洗脱后经抑制型电导检测器检测。结果 乳酸、富马酸和柠檬酸的线性范围分别为0.5～50.0、0.02～5.0和0.2～25 mg/L,相关系数分别为0.9985,0.9999和0.9992,方法检出限分别为0.04、0.01和0.03 mg/L,加标回收率为89.9%～112.5%,相对标准偏差为3.98%～6.99%（n = 6）。结论 该方法灵敏度高,操作简便快捷,适用于果汁中乳酸、富马酸和柠檬酸的同时测定。     

Effect of orange juice,folic acid,and oral contraceptives on serum folate in women taking a folate-restricted diet.

The effect of folate intake from orange juice on serum folate was evaluated in 60 women (age 20-39) during 9 weeks of a folate-restricted diet. Twenty-one were users of oral contraceptives (OCA). Folate intake from the restricted diet was 159 +/? 5 micrograms/day, as assessed by dietary surveys. Serum folate of women taking OCA was lower than in nonusers at the inception of the study (P less than 0.01). During the initial 2 weeks of restricted diet, serum folates decreased significantly (13.8 +/? 1.8 to 8.5 +/? 0.4 ng/ml; P less than 0.002). This decrease was further prevented by supplementation of the diet for 7 weeks with 100 micrograms/day of total folate from reconstituted frozen orange juice or synthetic folic acid (PteGlu). Both folate supplements were effective (P less than 0.05) in increasing serum folate (9.4 +/? 1.0 to 14.5 +/? 1.4 ng/ml, orange juice; 8.4 +/? 0.7 to 20.5 +/? 5.8 ng/ml, folic acid). Serum folates were similar in women taking either orange juice or folic acid. Serum folate of nonsupplemented women decreased from 10.2 +/? 0.8 to 8.3 +/? 0.4 ng/ml (P less than 0.05). No difference between serum folates of OCA users and nonusers was detected during the restricted diet or folate supplementation. These data indicate that folate in reconstituted orange juice was as available as folic acid, and that utilization of both folate forms and folate in a mixed diet was unaffected by oral contraceptives.     

中华猕猴桃汁的防癌作用——(二)在体外模拟胃液中对亚硝胺合成的阻断作用—Ames试验方法检测

本文研究了猕猴桃汁对N-二甲基亚硝胺体外合成的阻断作用,以鼠伤寒沙门氏菌致突变试验检验。 将二甲基亚硝胺的前体物质-亚硝酸钠和氨基比林,在体外模拟胃液条件下(pH3.3,37％℃)保温一小时,以鼠伤寒沙门氏菌变异株TA100,按常规方法(平皿掺入试验)检验致突变性。当两种前体浓度达5mg/ml以上时,如不加阻断剂,均显示出突变阳性反应,提示反应体系中形成了有致突变性的亚硝胺。如果同时加入猕猴桃汁,可以阻断亚硝胺合成,在5mg/ml和8mg/ml两个浓度的测定结果均未出现致突变作用。在5mg/ml反应体系中,分别加入桃汁和维生素C溶液进行对比,发现桃汁的阻断效率高于维生素C,每皿菌落数均值分别为252±4.2(桃汁),和445±81.2(同浓度维生素C),两者差异有显著性(P<0.01)。结果证明猕猴桃汁对体外亚硝胺合成的阻断作用优于同浓度的维生素C溶液。同样条件下单独保温的亚硝酸钠氨基比林或磷酸缓冲液均无致突变作用。 同样条件下处理的样品(亚硝酸钠,氨基比林各5mg/ml,加到pH3.3磷酸缓冲液中,37℃混合保温1小时)经水蒸气蒸馏,二氯甲烷萃取,浓缩后用气相色谱—质谱联机分析,确认为N-二甲基亚硝胺(NDMA)。     

火焰原子吸收光谱法和ICP - AES测定工作场所空气中多种金属元素的方法比较

目的 对工作场所空气中测定铬、铜、锰、镁、钠、镍、铅和钙的火焰原子吸收光谱法和电感耦合等离子发射光谱法（ICP - AES）进行比较。方法 采用硝酸高氯酸（9∶1,v/v）消化滤膜,定容至10 ml,用火焰原子吸收光谱法和电感耦合等离子发射光谱法分别测定。结果 火焰原子吸收光谱法的各元素标准曲线相关系数r值＞0.996,检出限≤0.033,加标回收率为95.4%～109.0%,相对标准偏差为0.36%～1.92%;电感耦合等离子发射光谱法的各元素标准曲线相关系数r值＞0.998,检出限≤0.0054,加标回收率为95.9%～102.6%,相对标准偏差为0.47%～1.90%。 结论 2种方法均具有良好的线性、准确度和精密度,检测结果无统计学差异。     

猕猴桃浓缩果汁中抗坏血酸在人体的利用

中华猕猴桃是我国的特产野果。鲜果中抗坏血酸含量一般在50～400mg/100g,最高可达2000mg/100g。制成浓缩汁后含量约为350～400mg/100ml。为观察其浓缩果汁中抗坏血酸的利用做了人体实验。受试者为9名男大学生,年龄19～23岁,平均体重56.0kg,身长166.6cm。实验分四期,第一及第三期为抗坏血酸饱和期;第二期为十天的对照期,食基础膳,以晶体抗坏血酸补足至每人每日摄入总量为75mg;第四期为十天的实验期,食基础膳,以猕猴桃汁补充抗坏血酸使每日每人摄入总量亦为75mg。对照期及实验期最后三天收集空腹1小时及24小时尿,最后2天取空腹血浆,皆用靛酚滴定还原型抗坏血酸含量。利用率系以实验期尿中排出率与对照期尿中排出率的比值而求得。算出猕猴桃汁中抗坏血酸利用率为94％。对照期及实验期最后三天24小时尿抗坏血酸排出分别为 20 1±1.63及18.8±1.22mg;空腹1小时尿分别为0.94±0.07及0.75±0.07mg。空腹血浆分别为0.83±0.04及0.81±0.02mg/100ml。分别作t试验,皆无显著性差异。并可看出每日供给75mg抗坏血酸可满足男大学生的需要,与以往报告基本一致。     

Survival of some species of Salmonella and Shigella in mukumbi, a traditional Zimbabwean wine

Mukumbi is a traditional Zimbabwean wine prepared from a fruit called mapfura by the Shona people of Zimbabwe and amaganu by the Ndebele. The majority of people in Africa call the tree marula (Sclerocarya birrea subspecies caffra). The survival of Salmonella group B, Salmonella enteritidis, Shigella sonnei and Shigella flexneri in unfermented and fermented mapfura (marula) juice (mukumbi) was investigated. It was found that within 30 min of inoculation, there were no longer any viable pathogens in the fermented mapfura juice whilst in the unfermented juice, more than 10(4) cfu/ml were still viable after 8 h. When lactic acid (0.25 mg/ml) was added to the unfermented mapfura juice, more than 10(4) cfu/ml were also still viable after 8 h but none were viable after 24 h. The fermented product, mukumbi, has a rapid antimicrobial effect against the pathogens as compared to the unfermented juice and is therefore safe from contamination with these pathogens. It appears thus that the death of the pathogens was due to other compounds besides the low levels of lactic acid.     

Consumption patterns of sweet drinks in a population of Australian children and adolescents (2003--2008)

ABSTRACT: BACKGROUND: Intake of sweet drinks has previously been associated with the development of overweight and obesity among children and adolescents. The present study aimed to assess the consumption pattern of sweet drinks in a population of children and adolescents in Victoria, Australia. METHODS: Data on 1,604 children and adolescents (4--18 years) from the comparison groups of two quasi-experimental intervention studies from Victoria, Australia were analysed. Sweet drink consumption (soft drink and fruit juice/cordial) was assessed as one day's intake and typical intake over the last week or month at two time points between 2003 and 2008 (mean time between measurement: 2.2 years). RESULTS: Assessed using dietary recalls, more than 70% of the children and adolescents consumed sweet drinks, with no difference between age groups (p = 0.28). The median intake among consumers was 500 ml and almost a third consumed more than 750 ml per day. More children and adolescents consumed fruit juice/cordial (69%) than soft drink (33%) (p < 0.0001) and in larger volumes (median intake fruit juice/cordial: 500 ml and soft drink: 375 ml). Secular changes in sweet drink consumption were observed with a lower proportion of children and adolescents consuming sweet drinks at time 2 compared to time 1 (significant for age group 8 to <10 years, p = 0.001). CONCLUSION: The proportion of Australian children and adolescents from the state of Victoria consuming sweet drinks has been stable or decreasing, although a high proportion of this sample consumed sweet drinks, especially fruit juice/cordial at both time points.