In addition, although the “milk powder suspected infant precocious puberty incident†has been repeatedly noticed by the Ministry of Health, “the hormone content in milk powder is not abnormalâ€, “the hormone test results show that infant precocious puberty has nothing to do with the milk powder consumedâ€, but people’s Doubt is still not eliminated - what causes precocious puberty in babies? Although many experts and researchers have analyzed the causes of precocious puberty, the author believes that in addition to food and physiological reasons, the impact of bisphenol A in PC plastic bottles or plastic catering appliances should not be ignored. Animal experiments have found that bisphenol A has the function of mimicking estrogen and is an endocrine disrupting substance.
What is Bisphenol A?
Bisphenol A scientific name 2,2-bis(4-hydroxyphenyl)propane, also known as diphenolyl propane, has the structure shown in the figure, and the English abbreviation is BPA. White needle crystals, melting point 156-158 ° C, molecular weight 228. Industrially, it is mainly produced by condensation of phenol and acetone in an acidic medium. BPA is mainly used for the preparation of epoxy resin (about 65%) and polycarbonate (about 35%). The potassium or sodium salt is a raw material for producing polysulfone, and a small amount is used as a rubber antioxidant. In the plastics manufacturing process, the addition of BPA makes it colorless, transparent, durable, lightweight and outstanding impact resistance, so it is widely used in canned food and beverage packaging, bottles, water bottles, space cups, sealants, And hundreds of other daily necessities in the manufacturing process. For example, some polycarbonate (PC) plastic containers such as baby bottles and space cups, the "ID card" of the container - the number in the triangle (usually at the bottom of the container) is 7, and will contain BPA.
What is the impact of BPA? Is there a usage limit?
In recent years, animal studies have found that BPA has the effect of mimicking estrogen, even at very low doses, it can cause females to have early maturity, decreased sperm count, and prostate growth. In addition, there are data showing that bisphenol A has certain embryotoxicity and teratogenicity, which can significantly increase the incidence of cancer such as ovarian cancer, prostate cancer and leukemia. Regarding whether BPA poses a hazard to human health, scholars from all walks of life have different opinions. From 2002 to 2008, many countries have conducted risk assessments of BPA, and it is generally believed that a certain amount of BPA is harmless to the human body. However, researchers in China in 2009 found that BPA affects the reproductive function of male occupational workers. In August 2010, the South African Cancer Society announced that after three years of research, it was further confirmed that BPA contained in plastic products is harmful to humans and may cause cancer and other serious health problems. The association concluded that BPA is a hormone-active endocrine disruptor that poses a potential threat to human health. The way BPA invades the human body is mainly inhalation and ingestion. Bottles or cups made of polycarbonate plastic will diffuse into the liquid such as milk, especially when the bottle is boiled by hot water or heated by microwave. BPA will be 55 times more.
Although some studies suggest that BPA in plastic products such as plastic bottles may affect the growth and development of infants and young children, and cause damage to children's brain and sexual organs, so far there is not enough evidence to prove that BPA ingredients released by infants or children due to PC bottle intake. And hurt. However, due to the results of various studies on BPA and the occurrence of adverse events, such as "BPA-containing baby bottles", many countries have reorganized the production and use of this chemical. For example, Canada first announced BPA as a hazardous chemical in 2008 and banned the use of BPA in the production of baby bottles. Last year and this year, the US states and the federal government have banned the use of chemical substances BPA in food and beverage containers such as baby bottles. Since last year, some European countries have begun to formulate a BPA ban.
However, so far, China has not issued a ban on BPA in certain areas, only in GB 13116-91 food containers and packaging materials for polycarbonate resin hygiene standards and GB 14942-94 food containers, packaging materials for polycarbonate The national standards such as ester molding hygienic standards stipulate that the dissolution of free phenol is not more than 0.05 mg/kg, and no specific provisions are made for the detection methods and limits of BPA. Therefore, the domestic community should also increase the level of attention to BPA.
How to detect BPA?
According to the literature, BPA detection methods mainly include high performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), spectrophotometry, enzyme-linked immunosorbent assay. Adsorption method (ELISA) and polarographic methods. GC-MS has high sensitivity (ppt level, ng/kg) but the sample preparation is complicated. In order to reduce the polarity and improve the sensitivity, it is necessary to analyze the sample after derivatization. Due to the limitation of UV detector, HPLC has low detection sensitivity (ppb level, μg/kg), which can not meet the needs of trace BPA residue detection, while the application methods such as spectrophotometry and ELISA are narrow. At present, the application of BPA is carried out by solid phase extraction (SPE), and the trace amount or trace amount of BPA residue is analyzed by LC-MS. The method has high sensitivity (ppt level) and selectivity. High in present. These assays are commonly used for BPA residue analysis, BPA toxicology studies, and related precision chemical analysis.
Other environmental endocrine disruptors (EDs)
In addition to BPA, endocrine disruptors (EDs) commonly found in the environment include nonylphenol, octylphenol, diethyl phthalate and dibutyl phthalate. Recently, an international environmental protection organization released an investigation report that it was found to contain nonylphenol and octylphenol in the wild rivers of Jiangyan and Jiangyan in the Yangtze River, causing an uproar. Nonylphenol and octylphenol are important fine chemical raw materials and intermediates, mainly used in the production of surfactants, also used in antioxidants, textile printing and dyeing auxiliaries, lubricant additives, pesticide emulsifiers, resin modification. Agents, resins and rubber stabilizers, etc., have biological toxicity, interfere with the endocrine system, can lead to sexual development and reproductive system problems such as female precocious puberty, promote breast cancer cell proliferation, and are suspected of being carcinogenic. The US Environmental Protection Agency (EPA) recommended that the content of nonylphenol in fresh water should not exceed 6.6 ppb and that salt water should not exceed 1.7 ppb. Phthalates are common chemical solvents and plasticizers that have irritating effects on the skin, eyes and respiratory tract. The mortality after blastocyst implantation is increased, which is toxic to the fetus and affects the musculoskeletal system of the fetus.
The development of EDs research is due to the rapid increase in the use of chemical industry, the migration and residue of such EDs in the environment is increasing, the researchers gradually focus on the specific impact and harm of EDs on human health and ecological environment. . In Europe, more than 300 laboratories have been involved in EDs research and 28 large joint research projects are underway. The US and Japanese governments have set up research institutions to be responsible for the comprehensive research work of EDs. Some domestic universities and research institutions have also carried out research on related content. With the gradual deepening of experimental research, accurate detection of trace and trace amounts has become a must, and pps of ppb and even ppt grades are the concentration range that researchers focus on. However, residual EDs in the environment lead to experimental analysis of water containing high background values, and studies and detection of trace and trace EDs will be affected.
Millipore's support for BPA and other EDs research The high-sensitivity detection method puts forward higher requirements for the analysis of experimental water, especially for EDs research experiments with ppb and ppt-level detection requirements, if the EDs residue in the experimental water reaches ppb or ppt Level, such a high background value will seriously affect the sensitivity and accuracy of the detection.
In this regard, in order to meet the research needs of EDs such as BPA, Millipore has developed a new ultra-pure water terminal filter EDS-Pak. The terminal filter is mainly composed of activated carbon and is used for removing common EDs such as BPA, nonylphenol, diethyl phthalate and dibutyl phthalate. The produced water can be used for the blank of EDs research experiments and reagent preparation. The filter can be installed in the outlet of the Millipore ultra-pure water system. The water requirement is ultra-pure water (TOC<5 ppb), which can produce at least 300 liters of ultra-pure water without EDs and provide a quality certificate.
EDS-Pak removes the challenging experimental results of four common EDs
| EDs test substance | Influent water (ppb) | Product water (ppt) | Volume (L) | Flow rate (L/min) |
| Bisphenol A | <4 | 300 | 0.5-2.0 | |
| Diethyl hthalate | <1.5 | 300 | 0.5-2.1 | |
| Di-n-butyl hthalate | <1.5 | 300 | 0.5-2.2 | |
| Nonylphenol | <3.3 | 300 | 0.5-2.3 |
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