Novel Diethyl Ether Gas Sensor Based on Cataluminescence on Nano-Pd/ZnNi3Al2O7.

A sensitive diethyl ether gas sensor based on cataluminescence on nano-Pd/ZnNi3Al2O7 at a temperature lower than 150 °C was reported. The composition of the sensitive material was determined by energy-dispersive spectrometry, and a particle size of less than 50 nm was shown by transmission electron microscopy. When the atomic percentage of Pd in the sensing material is 0.8-1.3%, it is beneficial to the low-temperature and high-selective cataluminescence of diethyl ether. The signal response and recovery of diethyl ether on the sensitive material can be completed quickly in 0.5 s, and the relative standard deviation of the signal within 500 h of continuous operation is not more than 2.5%. There is good linear relationship between the luminescence intensity and the concentration of diethyl ether in the range of 0.08-75 mg/m3. The detection limit (3σ) is 0.04 mg/m3. The working conditions optimized by the response surface methodology were an analytical wavelength of 548.86 nm, a reaction temperature of 109.18 °C, and a carrier gas velocity of 125.88 mL/min. The sensitivity of the method can be increased by 4.5% under the optimized working conditions. The optimization method is universal for many multi-parameter processes.

Determination of formaldehyde using a novel Pt-doped nano-sized sensitive material: Operating conditions optimization by response surface method.

High working temperature is the main obstacle in the design of chemiluminescence gas sensor. In this paper, a novel formaldehyde gas sensor based on chemiluminescence on nano-Pt/Mo4V6Ti10O47 at lower temperature than 200 °C was reported. Formaldehyde can be oxidized on the catalyst and emit chemiluminescence of specific wavelength. The relative standard deviation (RSD) of the chemiluminescence intensities within 600 h by continually introducing 20 mg/m3 formaldehyde is less than 3%. There is a good linear relationship between the chemiluminescence intensity and the concentration of formaldehyde in the range of 0.007-77.0 mg/m3. The limit of detection (3σ) is 0.002 mg/m3. The experimental operating conditions optimized by response surface method are analytical wavelength of 488.07 nm, working temperature of 138.13 °C and carrier gas velocity of 164.15 mL/min, respectively. The sensitivity of the method can be increased by 4.7% under the optimized working conditions, which is especially important for determination of trace substances. The optimization method is universal for most of multi parameter processes. The sensing properties and chemiluminescence mechanism of formaldehyde on nano-Pt/Mo4V6Ti10O47 were investigated.

Sensitive Carbon Monoxide Gas Sensor Based on Chemiluminescence on Nano-Au/Nd2O3-Ca3Nd2O6: Working Condition Optimization by Response Surface Methodology.

An Au/Nd2O3-Ca3Nd2O6 composite was synthesized by the sol-gel and impregnation method. The EDS spectrum and the transmission electron microscopy image showed that Au atoms are uniformly distributed on the surface of Nd2O3-Ca3Nd2O6 with a size of less than 50 nm. A sensitive carbon monoxide gas sensor based on chemiluminescence at a temperature lower than 200 °C was reported. There is a good linear relationship between the chemiluminescence intensity and the concentration of carbon monoxide in the range of 0.6-125 mg/m3. The detection limit (3σ) is 0.2 mg/m3. The working conditions optimized by the response surface methodology were an analytical wavelength of 620.90 nm, a reaction temperature of 131.63 °C, and a carrier-gas velocity of 105.46 mL/min. The sensitivity of the method can be increased by 4.5% under the optimized working conditions, which is especially important for the determination of trace substances. The carbon monoxide sensor demonstrated in this paper can be used for practical applications. The optimization method is universal for many multiparameter processes.

Determination of Progestin Residues in Fish by UPLC-Q-TOF/MS Coupled with QuEChERS.

A novel method was developed for simultaneous determination of 10 progestin residues in fish by ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) combined with a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The homogenized samples were dispersed by water, extracted with acetonitrile, and then purified by QuEChERS reagent. The concentrated analytes were detected by UPLC-Q-TOF/MS. High linearities (R 2 > 0.995) and recoveries (85.71-117.08%) at three spiked levels (5, 10, and 20 ng/g) and low relative standard deviation values (<8.83%, n = 7) and limits of detection (0.23-0.66 ng/g) were obtained. This method is simple, rapid, reliable, sensitive, and efficient and can be used for monitoring of progestin residues in fish. This method provides a strong guarantee to deal with food emergencies for the laboratory, provides technical support for the screening and quantitative detection of progesterone in fish, and provides technical support for the food safety of aquatic products.

[Simultaneous determination of chlorpromazine and promethazine and their main metabolites by capillary electrophoresis with electrochemiluminescence].

Based on the phenomenon that each of chlorpromazine (CPZ), promethazine (PMZ), chlorpromazine sulfoxide (CPZSO) and promethazine sulfoxide (PMZSO) could enhance the electrochemiluminescence (ECL) intensity of tris(2,2'-bipyridyl) ruthenium, a novel and sensitive method was proposed for the simultaneous determination of CPZ, PMZ and their main metabolites using capillary electrophoresis (CE) coupled with ECL detection. The influences of several experimental parameters were explored. The optimum experimental conditions were as follows: detection potential of 1. 20 V (Ag/AgCl), 40 mmol/L of phosphate buffer solution (pH 6.5) containing 5 mmol/L tris(2,2'-bipyridyl) ruthenium in ECL detection cell, running buffer solution of 18 mmol/L (pH 4.8), sample injection of 8 s at 11 kV, and separation voltage of 13.5 kV. The detection limits (3sigma) of this method were 8.3 x 10(-7) g/L for CPZ, 7.2 x 10(-6) g/L for PMZ, 1.9 x 10(-5) g/L for CPZSO and 3.7 x 10(-6) g/L for PMZSO. The linear ranges of ECL intensity versus mass concentration of medicaments were 7. 1 x 10(-6) - 6. 3 x 10(-3) g/L for CPZ, 7.5 x 10(-5) - 4.6 x 10(-3) g/L for PMZ, 9.7 x 10(-5) - 3.6 x 10(-3) g/L for CPZSO and 8.1 x 10(-5) - 7.7 x 10(-3) g/L for PMZSO. The relative standard deviations (RSDs) of the four target compounds were not more than 3% for ECL intensity and 1% for migration time. This method has the merits of simplicity, speediness, sensitivity, small sample injection, and free from interference. This method was successfully utilized to directly and simultaneously detect CPZ, PMZ, CPZSO and PMZSO in urine samples of pet dogs.