REMPI and IR-UV double resonance spectroscopy of 3-aminophenol·(NH3)1 cluster in the gas phase

The electronic and geometric structures of the cluster consisting of 3-aminophenol (3AP) and one ammonia molecule were investigated using resonance-enhanced multiphoton ionization and IR-UV double resonance spectroscopy in the gas phase. Between the cis and trans isomers found for the bare 3AP molecule, only trans isomer was found for 3AP·(NH₃)₁. It was found that complete quenching of the excited state of cis isomer, e.g. by conformer-specific excited state hydrogen transfer reaction, does not seem to occur, but that efficient conformational cooling drives the ground state population into the most stable trans isomer. The 0-0 band of the trans-3AP·(NH₃)₁ at 34 409 cm⁻¹ is red-shifted by 68 cm⁻¹ from that of the trans-3AP at 34 477 cm⁻¹. The IR depletion spectrum shows that the OH stretching vibration (3296 cm⁻¹) is red-shifted by 362 cm⁻¹ from that of the bare molecule. The large red-shift in OH frequency, combined with MP2 calculation, reveals that the structure of the cluster is the one with the nitrogen atom of ammonia bound to the hydroxyl hydrogen of aminophenol.     

Simultaneous Spectrophotometric Determination of Paracetamol and P‐Aminophenol by Using Mean Centering of Ratio Kinetic Profiles

A specific spectrophotometric method was developed for simultaneous determination of paracetamol (PCT) and p‐aminophenol (PAP) in water samples without prior separation steps. The method is based on the mean centering of ratio kinetic profiles. Paracetamol and P‐aminophenol react with Fe(III)/hexacyanoferrate(III) complex and result in the formation of colored complex, i.e. Prussian Blue. The differences in the rate of reaction of PCT and PAP with reagents make their simultaneous determination feasible by using mean centering of ratio kinetic profiles. The experimental parameters, such as reagent concentrations and pH were optimized for getting results with minimum errors. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) for the simultaneous determination of binary mixtures of p‐aminophenol and acetaminophen were calculated. The results show that the method was capable of simultaneous determination of 0.5–21.0 μg mL⁻¹ and 0.1–15.0 μg mL⁻¹ of PCT and PAP, respectively. The proposed method was successfully applied to the simultaneous determination of paracetamol and p‐aminophenol in several pharmaceutical products and synthetics mixtures.     

MAP-H2O2-HRP伏安酶联免疫分析测定南方菜豆花叶病毒

提出间氨基酚(MAP)-H₂O₂-辣根过氧化物酶(HRP)伏安酶联免疫分析新体系,并用于南方菜豆花叶病毒(SBMV)的测定.以线性扫描二阶导数伏安法检测HRP催化H₂O₂氧化MAP的产物,用于游离HRP及SBMV的测定,灵敏度均高于经典的ELISA显色光度法.本法对HRP测定的线性范围为1.0×10^-8～1.0×10^-6g/L,检测限为3.8×10^-9g/L;对SBMV测定的线性范围为4.0～5000ng/mL,检测限为4.0ng/mL.用所建立的方法测定病毒感染病叶澄清液的最高稀释比为1∶1.5×10⁵,并与现行的ELISA显色光度法进行对照,二者相关性很好.