组织及生物类样品中汞、总汞、汞含量、重金属检测方案(测汞仪)

DIRECT AA MERCURY DETERMINATION IN TISSUES AND BIOSAMPLES INTRODUCTION Mercury and its compounds are highly toxic substances for humans. It occurs naturally and exists in various forms: elemental (or metallic); inorganic (e.g. mercuric chloride); and organic (e.g., methyl- and ethylmercury). These forms all have different toxicities and implications for health. Among naturally occurring mercury compounds, methylmercury exerts a significant influence (neurotoxic action) on human health. The toxic properties of methylmercury are caused by the ability of its ions to bond with sulfhydryl groups of proteins. This changes proteins’ structure and properties, resulting in disfunction of the protein metabolism and the course of enzymatic processes. Mercury exposure level is determined by analysis of blood, hair, nails and other biosamples. For an acute type of poisoning, the diagnosis is confirmed both by clinical presentation and by results of analysis of body fluids (urine, blood, saliva). In case of chronic poisoning the situation is complicated. Mercury concentration in urine may rapidly decrease after the termination of exposure to mercury, whereas it may be high in internal organs for a long time because mercury is prone to accumulate in liver, kidneys, spleen, brain, and hair. In this case, the analysis of hair provides more information about mercury concentration in the body because they hold the trapped mercury for much longer time. The use of atomic absorption mercury analyzer RA-915M with Zeeman background correction equipped with PYRO-915+ pyrolytic attachment provides direct mercury determination in biological samples at a ppb level. MEASUREMENT METHOD The measuring method is based on thermal atomization of mercury from a sample using a PYRO-915+ attachment and its consequent determination by flameless AAS with Zeeman background correction using a RA-915M mercury analyzer. A sample is placed into the sample boat, which is inserted into the first chamber of the atomizer, where the sample is heated at a temperature of 200–800°C (depending on the selected operation mode). The mercury compounds are evaporated and partially dissociated, forming elemental mercury. All the gaseous products formed are transported into the second chamber of the atomizer by a carrier gas (ambient air). Mercury compounds are totally dissociated and the organic matrix of the sample is burnt out. Downstream from the atomizer the air flow enters the analytical cell heated up to 700°C, and the mercury atoms are detected by RA-915M analyzer. This approach does not involve preconcentration on a gold trap and “cooling step”, thereby eliminating ensuing problems. The use of ZAAS combined with a “dry” converter provides the highest sensitivity with no interferences from the sample matrix. Purified ambient air is used for combustion, so that no cylinders with oxidizer or compressed gases and “clean room” environment are required. The total time needed for determination of mercury is not longer than 2 minutes. MEASUREMENT RANGE Sample Sample weight, mg Measurement range, µg/kg Hair 5–50 0.5–500 Nail 5–50 Urine 50–200 Skin 5–300 Saliva 50–200 Tissues 5–300 Whole blood 50–200 ANALYSIS FEATURES Sample digestion process with strong acids is not necessary. Sample homogenization is enough as sample preparation. Control of non-selective absorption during the measurement process allows optimizing of sample weight and reduces analysis errors. Rapid analysis. Low running cost (Needs no chemical reagent). SRMs with any matrix (both liquid and solid) can be used for calibration. EQUIPMENT AND REAGENTS The following equipment and materials are used for analysis: Mercury analyzer RA-915M with PYRO-915+ attachment; PC with Windows® ХР/Vista/7/8 and RAPID software; SRM of mercury. The information in this leaflet is supplemental. To get more specific information on this method, please contact the developer of this method LUMEX INSTRUMENTS Group. NORTH AMERICA Lumex Instruments Canada 0890278 B.C. Ltd. E-mail: info@lumexinstruments.com www.lumexinstruments.com EUROPE Lumex Analytics GmbH E-mail: info@lumexanalytics.de www.lumexanalytics.de RUSSIA Lumex-Marketing LLC E-mail: sales@lumex.ru www.lumexinstruments.com CHINA Beijing Lumex Analytical Equipment Co. Ltd. E-mail: lumex@lumex.com.cn www.lumexcn.com ( 2 ) 汞及其化合物是人体的高毒物质。它在自然界以各种形式存在：元素态（或金属态）；无机物（例如氯化汞）和有机物（例如甲基汞和乙基汞）。汞的这些存在形式都有不同的毒性，并且对人体健康有不同程度的影响。在天然存在的汞化合物中，甲基汞对人体健康具有最显著影响（神经毒性作用）。甲基汞的毒性是由其离子与蛋白质巯基结合的能力引起的。这改变了蛋白质的结构和性质，导致蛋白质代谢紊乱和导致酶促过程。汞含量水平的检测是通过分析血液、头发、指甲和其他生物样品来确定的。对于急性中毒，通过临床观察和体液（尿液、血液、唾液）的分析结果来证实诊断。而慢性中毒的情况比较复杂。在尿液排出后，尿液中的汞浓度可能迅速下降，而在内脏器官中汞浓度可能高达很长一段时间，因为汞容易积聚在肝脏、肾脏、脾脏、大脑和毛发中。在这种情况下，毛发的分析提供了更多关于体内汞浓度的信息，因为毛发可以更长时间地对汞进行吸附和保存。原子吸收汞分析仪RA-915M的塞曼背景校正配备了PYRO-915+热解附件可直接汞测定生物样品，检出限在ppb级。