Overview
Methyl Red is an azo dye widely recognized as a pH indicator in analytical chemistry and microbiological applications. First synthesized in the early 20th century, it remains a standard reagent in laboratories worldwide. The compound's distinct color change between pH 4.4 (red) and 6.2 (yellow) makes it particularly valuable for titration experiments and microbial culture media. The term 'analytical purity' (分析纯) refers to reagents meeting Chinese GB/T standards for laboratory use, typically with purity ≥99%. Methyl Red of analytical grade undergoes rigorous testing for impurities like heavy metals and insolubles, ensuring consistent performance in sensitive applications.
Physical and Chemical Properties
As an azo compound, Methyl Red features a diazo (-N=N-) group connecting aromatic rings, which accounts for its vivid coloration and pH sensitivity. The crystalline powder shows moderate stability under normal conditions but may degrade upon prolonged exposure to strong light or oxidizing agents. Its limited water solubility necessitates ethanol or acetic acid as preferred solvents for preparing indicator solutions. Thermal analysis reveals decomposition before boiling, with the melting point serving as a key quality control parameter. The molecular weight (269.30 g/mol) is critical for preparing molar solutions. When dissolved, the compound exhibits maximum absorbance at 410-430 nm, a property utilized in spectrophotometric methods.
Main Applications
In microbiology, Methyl Red forms part of the MR-VP test for identifying enteric bacteria based on their glucose fermentation patterns. Escherichia coli typically produces a positive red result, while Enterobacter species yield negative (yellow) readings. This application remains vital in clinical and food safety testing. The dye also serves in educational chemistry demonstrations, industrial process monitoring, and as a component in multi-range pH test papers. Recent research explores its potential in photodynamic therapy and as a staining agent for microscopic analysis, though these applications require specialized purity grades beyond standard analytical reagents.
Safety and Storage
As a moderately hazardous substance, Methyl Red requires proper handling with PPE including gloves and eye protection. The powder can generate irritant dust, necessitating use in fume hoods during weighing. Spills should be contained with absorbent materials and cleaned promptly to prevent environmental contamination. Long-term storage stability is achieved in amber glass bottles at room temperature (15-25°C) with low humidity. Suppliers typically provide a shelf life of 2-3 years from production date. Degradation signs include color fading or solution precipitation. For bulk quantities, climate-controlled warehouses with fire prevention measures are recommended due to the compound's combustible nature.
B2B Procurement Guide
Industrial buyers should prioritize suppliers with ISO 9001 certification and batch-specific Certificates of Analysis (CoA). Key specifications include dye content (≥95% for analytical grade), pH transition range verification, and heavy metal limits (typically <10ppm). Packaging options range from 25g vials to 25kg fiber drums, with larger volumes offering better per-unit costs. Due to fluctuating raw material costs, request updated price lists and consider long-term contracts for stable supply. Verify shipping complies with chemical transport regulations (UN proper shipping name: 'Environmentally hazardous substance, solid, n.o.s.'). For international procurement, confirm the supplier's experience with export documentation including MSDS, commercial invoices, and hazardous material declarations.
Related Manufacturers
- 主营：合成树脂、固化剂、不饱和树脂、甲基红AR、环氧树脂、聚酯多元醇、酚醛树脂、医药中间体
- 主营：抗氧剂、乳化剂、苯扎氯铵、分析纯、烷基二甲基、氢化蓖麻油、表面活性剂、双链季胺盐、聚氧乙烯醚、二丁基羟基甲苯、甘油聚氧丙烯醚、十二烷基硫酸钠、树脂、助剂
- 主营：甲酚红、刚果红、龙胆紫、甲基红钠、孔雀石绿、邻菲罗啉、二甲酚橙、玫瑰苯胺、化学试剂、金属指示剂、荧光指示剂、酸碱指示剂、碱性玫瑰精、石蕊掘试剂
- 主营：亚索化学试剂、化学试剂、生物试剂、分析纯AR试剂、滴定分析试剂、检测试剂、化学色谱纯试剂、光谱纯试剂、优级纯GR试剂、基准试剂、高纯电子级试剂、标准化学试剂、实验室试剂、通用试剂
- 主营：工业盐、精制工业盐、工业海盐、甲基红价格、软水盐、融雪剂、氯化钙、焦亚硫酸钠、小苏打、柠檬酸、纯碱、羧甲基纤维素、草酸、活性炭、尿素、葡萄糖、聚合氯化铝、聚丙烯酰胺、活性白土、氯化铵、硫酸铵、硫酸亚铁、磷酸三钠、反渗透阻垢剂、氢氧化钙
- 主营：甲基红、对照品、标准品
- 主营：塑料助剂、精炼石蜡、化工催化剂、甲基红、回收过期染料、回收气相白炭黑、回收油漆、回收树脂、回收钛白粉、回收日化原料、回收橡胶原料
- 主营：阻燃剂、乙酸镍、乙酸镝、对甲基红、硫酸锂、硫酸锶、溴氨酸、香茅醇、肌氨酸、锂电池、四氢萘、磷酸铬、碳酸镁、碳酸镍、防冻剂、磷酸铝、叔丁醇、氟苯基、浮选剂、稀释剂、羟乙基、去除剂、庚二酸、除磷剂、十八烯、蛋白酶
- 主营：乙二醇、二甲基亚砜、丙二醇、对甲基红、精对苯二甲酸、己二酸、聚乙烯醇、聚乙二醇、木质素、甘油、三甘醇、己内酰胺、叔十二硫醇、白油、对苯二甲酸二甲酯、4-丁二醇
- 主营：三硫代碳酸钠、红色素-16、聚乙烯亚胺、间甲基红、三乙二醇二异辛酸酯、巯基苯并噻唑钠、L-丙交酯、乙交酯、石油酯-T50、多元醇苯甲酸酯、热压敏染料、光稳定剂、高分子降解材料
- 主营：乙二醇、甘油、防冻液、甲基红、丙三醇
- 主营：异丙醇、冰醋酸、化工原料、甲基红、正庚烷、甲基环己烷、乙二醇、苯酚、江苏异丙醇、江苏化工原料、工业吡啶、工业苯酚、正丁醇、MIBK、无水乙醇、正己烷
- 主营：全氟聚醚二醇、全氟三丁胺、聚硅氮烷、甲基红钠盐、特种硅油、特种硅树脂
- 主营：甲基红、全氟三丁胺、木质素、吉氏色素
- 主营：甲酸镍、水苏糖、阻燃剂、甲基红、柠檬醛、西瓜酮、氢醌酯、卡必醇、消泡剂、磷酸铁、肉桂醇、肉桂醛、碳酸镉、磷酸铝、银墨水、椰油胺、封装胶、化合物、桦木油、稀释剂、羟乙基、乙硫氮、润肤剂、球虫酯、矮壮素、异龙脑
- 主营：全氟三丁胺、二苄叉山梨醇、六氟丙烯二聚体、甲基红、六氟环氧丙烷二聚体、异丙醇铝、纳米勃姆石、二异戊基硫醚、隐色结晶紫、邻菲罗啉
- 主营：架桥剂、YW100 锂萃取剂、端羧基液体丁腈橡胶、甲基红、10-羟基癸酸、苯乙烯磷酸、肉豆蔻酸镁、硬脂酸钴、全氟三丁胺、乙烯基磷酸二乙酯、磷酸锰铁锂、β-磷酸三钙、十一烯酸、钨酸铝、1-乙炔基环已醇、间二异丙苯、锂硅合金、溴甲酚绿、生物活性玻璃、溴代海因树脂颗粒、红铝、龙涎酮、原丁酸三甲酯
- 主营：甘氨酸、水苏糖、阻燃剂、甲基红指示液、硫酸锌、硫酸锆、硫酸锂、硫酸锶、硫酸锰、铝酸锌、1680-21-3、牛磺酸、褪黑素、磷酸铁、丙酸铵、苏云金、碳酸镁、麝香酮、肉桂醛、磷酸铝、王浆酸、椰油胺、赖氨酸、增塑剂、浸膏粉、乙氧基
- 主营：有机原料、中间体、香精香料、甲基红、催化剂、有机硅、表面活性剂