Identification and determination of by‐products originating from ozonation of chlorpyrifos and diazinon in water by liquid chromatography–mass spectrometry

Abstract

The degradation of two organophosphates, chlorpyrifos and diazinon, in water using microplasma equipment to produce ozone and the identification of their products were studied by using liquid chromatography–mass spectrometry. The organophosphates gradually decreased with time and were completely removed after 10 min, and diazinon was degraded at a relatively fast rate compared to chlorpyrifos. The products formed during the process were identified and determined with accurate mass measurements and tandem mass spectrometry spectra, providing reliable structural determination. Chlorpyrifos oxon was formed through the oxidation of chlorpyrifos, followed by the formation of 3,5,6‐trichloro‐2‐pyridinol and diethyl phosphate by hydrolysis. Diazinon formed various products through more complicated degradation processes than those of chlorpyrifos. The major products of diazinon degradation were 2‐isopropyl‐6‐methyl‐4‐pyrimidinol and diethyl phosphate by hydrolysis after oxidation, exhibiting diazoxon as an intermediate at trace levels. Direct hydrolysis of diazinon also occurred, producing diethyl thiophosphate, which was observed at a low concentration for a transient time and exhibited a less favorable process than sequential oxidation and hydrolysis. The other products, hydroxy diazinons and hydroxy‐2‐isopropyl‐6‐methyl‐4‐pyrimidinols, formed by hydroxylation, were also identified, but they were present in low amounts. Degradation mechanisms of chlorpyrifos and diazinon were proposed with the quantitatively evaluated products.

A simple AuNPs-based colorimetric aptasensor for chlorpyrifos detection

“…Besides, exposure to Chl also has great threat to human health, such as affect male reproduction [4], neurotoxicity [5], nephrotoxicity [6], induce the proliferation of breast cancer cells [7,8] and acute toxicity [9]. Thus, the toxicity of Chl to environment and humans lead to urgently exploit sensitive, simple, low cost and on-site rapid methods for Chl analysis and detection, since the instrumental techniques (high performance liquid chromatography [10,11], gas chromatography [12], mass spectrometry [13], surface enhanced Raman scattering [14], etc.) have the storages of bulky to carry, expensive cost, professional operators and complexity sample pre-treatment.…”

A modified quick, easy, cheap, effective, rugged, and safe method for determination of by‐products originating from ozonation of chlorpyrifos and diazinon spiked in cherry tomato and perilla leaf

“…In our previous study [25], quantitative analysis was performed for by-products formed from the selected OPs through various decomposition processes during ozonation in water. The representative products were confirmed as DEP, TCP, and CPO, which originated from CP, and DEP, IMP, and DZO, which originated from DZ.…”

“…The ESI spray voltage was set to 3500 V for positive ion mode. Data were collected in multiple reaction monitoring mode under the conditions listed in Table 1, as optimized by our previous paper [25]. For data acquisition and quantitative calculations, Agilent MassHunter Quantitative Analysis software version B.07.00 was used.…”

“…In a previous study, using LC-MS techniques, we profiled the by-products of chlorpyrifos (CP) and diazinon (DZ) decomposed by microplasma equipment generating ozone [25]. The major degradation processes producing the by-products were oxidation and hydrolysis, and the behavior of their formation over time was evaluated in aqueous media.…”

A simple AuNPs-based colorimetric aptasensor for chlorpyrifos detection

“…Besides, exposure to Chl also has great threat to human health, such as affect male reproduction [4], neurotoxicity [5], nephrotoxicity [6], induce the proliferation of breast cancer cells [7,8] and acute toxicity [9]. Thus, the toxicity of Chl to environment and humans lead to urgently exploit sensitive, simple, low cost and on-site rapid methods for Chl analysis and detection, since the instrumental techniques (high performance liquid chromatography [10,11], gas chromatography [12], mass spectrometry [13], surface enhanced Raman scattering [14], etc.) have the storages of bulky to carry, expensive cost, professional operators and complexity sample pre-treatment.…”