A Highly Selective and Sensitive Fluorescent Probe for pH.

A new, highly selective, and sensitive fluorescent probe for pH measurement was developed. This pH fluorescent probe, N,N'-bis-salicylaldehydedimine-1,8-diaminonaphthalene, was synthesized with 1,8-diaminonaphthalene and salicylaldehyde. The results demonstrated that this pH fluorescent probe was sensitive. It switched in a significantly narrow pH range within about 1.5 units from pH 1.99 to 3.49, which would be very useful in the life sciences and other fields.

Development of sensitive determination method for fungicides from environmental water samples with Titanate nanotube array micro-solid phase extraction prior to high performance liquid chromatography.

Fungicides have been widely used throughout the world, and the resulted pollution has absorbed great attention in recent years. Present study described an effective measurement technique for fungicides including thiram, metalaxyl, diethofencarb, myclobutanil and tebuconazole in environmental water samples. A micro-solid phase extraction (µSPE) was developed utilizing ordered TiO(2) nanotube array for determination of target fungicides prior to a high performance liquid chromatography (HPLC). The experimental results indicated that TiO(2) nanotube arrays demonstrated excellent merits on the preconcentration of fungicides, and excellent linear relationship between peak area and the concentration of fungicides was obtained in the range of 0.1-50 µg L(-1). The detection limits for the targeted fungicides were in the range of 0.016-0.086 µg L(-1) (S/N=3). Four real environmental water samples were used to validate the applicability of the proposed method, and good spiked recoveries in the range of 73.9-114% were achieved. A comparison of present method with conventional solid phase extraction was made and the results exhibited that proposed method resulted in better recoveries. The results demonstrated that this µ-SPE technique was a viable alternative for the analysis of fungicides in complex samples.

Investigation of the applicability of highly ordered TiO2 nanotube array for enrichment and determination of polychlorinated biphenyls at trace level in environmental water samples.

Present study investigated the applicability of ordered TiO(2) nanotube arrays for the enrichment and determination of polychlorinated biphenyls (PCBs) in water samples. A new and reliable method was developed for the preconcentration and determination of PCBs by micro-solid phase equilibrium extraction in combination with gas chromatography and electron capture detection (GC-ECD), which exploited the special physical and chemical properties of ordered TiO(2) nanotube arrays. The experimental results indicated that low LODs were easily achieved in the range of 0.02-0.10 µg L(-1) for PCB-28, PCB-52, PCB-101, PCB-153, PCB-138, and PCB-180. The proposed method was validated with several real water samples, and good spiked recoveries have been obtained in the range of 95.8-110.5%. The experimental results demonstrated that TiO(2) nanotube arrays could be reused for over 200 times without the lost of the extraction efficiency. All these showed that TiO(2) nanotube arrays would be very useful in the enrichment and determination of trace pollutants.

Development of micro-solid phase extraction with titanate nanotube array modified by cetyltrimethylammonium bromide for sensitive determination of polycyclic aromatic hydrocarbons from environmental water samples.

This paper described a simple and novel analytical technique for the determination of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. A micro-solid phase extraction (µ-SPE) was developed utilizing cetyltrimethylammonium bromide modified ordered TiO(2) nanotube array. The experimental results indicated that modified TiO(2) nanotube arrays demonstrated an excellent merit on the preconcentration of PAHs, and there were excellent linear relationships between peak area and the concentration of PAHs in the range of 0.2-100 µg L(-1) and 1.0-100 µg L(-1), respectively. The detection limits of proposed method for the targeted PAHs were in the range of 0.026-0.82 µg L(-1) (S/N = 3). The real-world environmental water samples were used to validate the applicability of the proposed method and good spiked recoveries were in the range of 75.0-114%. All these results demonstrated that this new µ-SPE technique was a viable alternative to conventional enrichment techniques for the extraction and analysis of PAHs in complex samples.

Establishment of trace determination method of pyrethroid pesticides with TiO2 nanotube array micro-solid phase equilibrium extraction combined with GC-ECD.

This paper described a new method for the enrichment and determination of pyrethroid pesticides from environmental water samples with ordered TiO(2) nanotube array micro-solid phase equilibrium extraction (µ-SPEE) prior to gas chromatography (GC) with electron capture detection (ECD). Several factors such as the anodization voltage, the kind of organic solvents, sample pH, equilibrium extraction time, desorption time and salting-out effect were optimized. Under the optimal conditions, ordered TiO(2) nanotube arrays demonstrated excellent merits on the preconcentration of pyrethroid pesticides and good detection limits were achieved as 0.018, 0.020, 0.031, 0.041, and 0.070 µg L(-1) for bifenthrin, fenpropathrin, cyhalothrin, fenvalerate, and deltamethrin, respectively. Four real water samples were used to validate the proposed method and the spiked recoveries were over the range of 81.9-110.6%. Compared to conventional solid phase extraction (SPE), the present method showed better recoveries and good reproducibility. These results showed that this µ-SPEE technique could be an important alternative to multistep SPE for the extraction and determination of such analytes in complex samples and become a useful tool in monitoring such analytes in the environment.

Micro-solid phase equilibrium extraction with highly ordered TiO2 nanotube arrays: a new approach for the enrichment and measurement of organochlorine pesticides at trace level in environmental water samples.

Ordered TiO(2) nanotube arrays have been widely used in many fields such as photocatalysis, self-cleaning, solar cells, gas sensing, and catalysis. This present study exploited a new functional application of the ordered TiO(2) nanotube arrays. A micro-solid phase equilibrium extraction using ordered TiO(2) nanotube arrays was developed for the enrichment and measurement of organochlorine pesticides prior to gas chromatography-electron capture detection. Ordered TiO(2) nanotube arrays exhibited excellent merits on the pre-concentration of organochlorine pesticides and lower detection limits of 0.10, 0.10, 0.10, 0.098, 0.0076, 0.0097, 0.016, and 0.023 µg L(-1) for α-HCH, ß-HCH, γ-HCH, δ-HCH, p,p'-DDE, p,p'-DDD, o,p'-DDT, and p,p'-DDT, respectively, were achieved. Four real water samples were used for validation, and the spiked recoveries were in the range of 78-102.8%. These results demonstrated that the developed micro-solid phase equilibrium extraction using ordered TiO(2) nanotube arrays would be very constructive and have a great beginning with a brand new prospect in the analysis of environmental pollutants.

Determination of trace organophosphorus pesticides in water samples with TiO2 nanotubes cartridge prior to GC-flame photometric detection.

This article described a new method for the sensitive determination of organophosphorus pesticides in water samples using SPE in combination with GC-flame photometric detection. In the procedure of method development, TiO(2) nanotubes were used as SPE adsorbents for the enrichment of organophosphorus pesticides from water samples. Several factors, such as eluent and its volume, sample pH, sample volume, sample flow rate, and concentration of humic acid, were optimized. Under the optimal conditions, the proposed method had good linear ranges as 0.1-40 microg/L for each of them, LOD of 0.11, 0.014, and 0.0025 microg/L, and LOQs of 0.37, 0.047, and 0.0083 microg/L for chlorpyrifos, phorate, and methyl parathion, respectively. The proposed method was validated with real environmental water samples and the spiked recoveries were over the range of 86.5-115.1%. All these results indicated that TiO(2) nanotubes, as a new SPE adsorbent, would be used widespread for the preconcentration and determination of environmental pollutants in the future.