2-(2-喹啉偶氮)-1,5-苯二酚固相萃取光度法测定银的研究

研究了新试剂 2 (2 喹啉偶氮 ) 1,5 苯二酚 (QADHB)与银的显色反应 ,在 pH =5 0柠檬酸 氢氧化钠 (内含 0 0 1mol·L- 1 Na2 EDTA)缓冲介质中 ,十二烷基磺酸钠 (SDS)存在下 ,QADHB与银反应生成摩尔比为 2∶1的稳定络合物 ,该络合物可被WatersSep ParkC1 8固相萃取小柱萃取富集。富集在小柱上的络合物用乙醇 (含 1%乙酸 )洗脱后 ,在乙醇介质中 ,其吸收光谱的λmax=5 5 0nm ,ε=6 99× 10 4 L·mol- 1 ·cm- 1 。银含量在 0～ 1 2 μg·mL- 1 范围内符合比尔定律。方法用于环境水样中痕量银的测定 ,结果令人满意

Study on Spectrophotometric Determination of Silver(Ⅰ) with 2-(2-Quinolinylazo)-1, 5-Dihydroxidebenzene

The color reaction of silver(I) with 2-(2-quinolinylazo)-1,5-dihydroxidebenzene (QADHB) and the solid phase extraction of the colored chelate with Waters Sep-Park C18 cartridge were developed. In the presence of pH = 5.0 sodium citrate-sodium hydroxide buffer solution and sodium dodecyl sulfonate (SDS) medium, QADHB can reacts with silver to form a chelate of a molar ratio 1:2 (silver to QADHB). This chelate can be enriched by the solid phase extraction with Waters Sep-Park C18 cartridge. The retained chelate can be eluted from cartridge with ethanol. In ethanol medium, the molar absorptivity is 6.99 x 10(4) L x mol(-1) x cm(-1) at 550 nm. Beer's law is obeyed in the range of 0-1.2 microg x mL(-1). This method can be applied to the determination of silver in water with satisfactory results.