Honglan Shi

Investigation of Pharmaceuticals in Missouri Natural and Drinking Water Using High Performance Liquid Chromatography-Tandem Mass Spectrometry

A comprehensive method has been developed and validated in two different water matrices for the analysis of 16 pharmaceutical compounds using solid phase extraction (SPE) of water samples, followed by liquid chromatography coupled with tandem mass spectrometry. These 16 compounds include antibiotics, hormones, analgesics, stimulants, antiepileptics, and X-ray contrast media. Method detection limits (MDLs) that were determined in both reagent water and municipal tap water ranged from 0.1 to 9.9 ng/L. Recoveries for most of the compounds were comparable to those obtained using U.S. EPA methods. Treated and untreated water samples were collected from 31 different water treatment facilities across Missouri, in both winter and summer seasons, and analyzed to assess the 16 pharmaceutical compounds. The results showed that the highest pharmaceutical concentrations in untreated water were caffeine, ibuprofen, and acetaminophen, at concentrations of 224, 77.2, and 70 ng/L, respectively. Concentrations of pharmaceuticals were generally higher during the winter months, as compared to those in the summer due, presumably, to smaller water quantities in the winter, even though pharmaceutical loadings into the receiving waters were similar for both seasons.

Characterization of gold nanoparticle uptake by tomato plants using enzymatic extraction followed by single-particle inductively coupled plasma-mass spectrometry analysis.

Plant uptake and accumulation of nanoparticles (NPs) represent an important pathway for potential human expose to NPs. Consequently, it is imperative to understand the uptake of accumulation of NPs in plant tissues and their unique physical and chemical properties within plant tissues. Current technologies are limited in revealing the unique characteristics of NPs after they enter plant tissues. An enzymatic digestion method, followed by single-particle inductively coupled plasma-mass spectrometry (SP-ICP-MS) analysis, was developed for simultaneous determination of gold NP (AuNP) size, size distribution, particle concentration, and dissolved Au concentration in tomato plant tissues. The experimental results showed that Macerozyme R-10 enzyme was capable of extracting AuNPs from tomato plants without causing dissolution or aggregation of AuNPs. The detection limit for quantification of AuNP size was 20 nm, and the AuNP particle concentration detection limit was 1000 NPs/mL. The particle concentration recoveries of spiked AuNPs were high (79-96%) in quality control samples. The developed SP-ICP-MS method was able to accurately measure AuNP size, size distribution, and particle concentration in the plant matrix. The dosing study indicated that tomato can uptake AuNPs as intact particles without alternating the AuNP properties.

Comprehensive profiling of isoflavones, phytosterols, tocopherols, minerals, crude protein, lipid, and sugar during soybean (Glycine max) germination.

Isoflavone, phytosterol, tocopherol, mineral, protein, lipid, and sugar contents of soybeans were analyzed during 7-day germination with or without exposure to light. The levels of phytosterols and tocopherols increased significantly during the 3 day germination. Although malonyl glycosides were the predominant forms of isoflavones in soybean seeds, 77% of malonyl daidzin and 30% of malonyl genistin were converted to corresponding daidzin, daidzein, genistin, and genistein during the germination period. Slight decreases in malonal glycidin and malonyl glycidin concentrations were also observed while the total molar concentration of isoflavones remained constant. An increase of approximately 4% in the protein level was accompanied by a 5-6% reduction in the carbohydrate and lipid contents after the 7-day germination. Mineral (Ca, Cr, Fe, Zn Cu, K, Mg, Mn) levels did not vary much during germination, and the presence of light during germination had only a little, if any, effect on the levels of the micro- and macronutrients in soybeans.

Oxidative removal of selected endocrine-disruptors and pharmaceuticals in drinking water treatment systems, and identification of degradation products of triclosan

The potential occurrences of endocrine-disrupting compounds (EDCs), as well as pharmaceuticals, are considered to be emerging environmental problems due to their persistence and continuous input into the aquatic ecosystem, even at only trace concentrations. This study systematically investigated the oxidative removal of eight specially selected ECDs and pharmaceuticals by comparing their relative reactivity as a function of different oxidative treatment processes (i.e., free chlorine, ozone, monochloramine, and permanganate) under various pH conditions. For the oxidative removal study, EDC and pharmaceutical standards were spiked into both deionized water and natural water, followed by treatment using common oxidants at typical water treatment concentrations. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for identification and quantification. The removal efficiency of the EDCs and pharmaceuticals varied significantly between oxidation processes. Free chlorine, permanganate, and ozone treatments were all highly effective at the elimination of triclosan and estrone, while they were not effective for removing ibuprofen, iopromide, and clofibric acid. Monochloramine (at a dose of 3mg/L) was mostly ineffective in eliminating any of the selected EDCs and pharmaceuticals under the tested conditions. pH also played an important role in the removal efficiency of the EDCs and pharmaceuticals during free chlorine, permanganate, and ozone treatments. Additionally, the study identified the oxidation products of triclosan by permanganate, and 2,4-dichlorophenol was identified as the major oxidation product of triclosan by permanganate in drinking water system treatment. Furthermore, 2,4-dichlorophenol was further degradated to 4,5-dichloro-2-(2,4-dichlorophenoxy)phenol and/or 5,6-dichloro-2-(2,4-dichlorophenoxy)phenol. The kinetics for this reaction indicated that the reaction was first order in the drinking water system.

Assessment of metal contaminations leaching out from recycling plastic bottles upon treatments

Background, aims, and scopeHeavy metal contaminants in environment, especially in drinking water, are always of great concern due to their health impact. Due to the use of heavy metals as catalysts during plastic syntheses, particularly antimony, human exposure to metal release from plastic bottles has been a serious concern in recent years. The aim and scope of this study were to assess metal contaminations leaching out from a series of recycling plastic bottles upon treatments.MethodologyIn this study, leaching concentrations of 16 metal elements were determined in 21 different types of plastic bottles from five commercial brands, which were made of recycling materials ranging from no. 1 to no. 7. Several sets of experiments were conducted to study the factors that could potentially affect the metal elements leaching from plastic bottles, which include cooling with frozen water, heating with boiling water, microwave, incubating with low-pH water, outdoor sunlight irradiation, and in-car storage.ResultsHeating and microwave can lead to a noticeable increase of antimony leaching relative to the controls in bottle samples A to G, and some even reached to a higher level than the maximum contamination level (MCL) of the US Environmental Protection Agency (USEPA) regulations. Incubation with low-pH water, outdoor sunlight irradiation, and in-car storage had no significant effect on antimony leaching relative to controls in bottle samples A to G, and the levels of antimony leaching detected were below 6 ppb which is the MCL of USEPA regulations. Cooling had almost no effect on antimony leaching based on our results. For the other interested 15 metal elements (Al, V, Cr, Mn, Co, Ni, Cu, As, Se, Mo, Ag, Cd, Ba, Tl, Pb), no significant leaching was detected or the level was far below the MCL of USEPA regulations in all bottle samples in this study. In addition, washing procedure did contribute to the antimony leaching concentration for polyethylene terephthalate (PET) bottles. The difference of antimony leaching concentration between washing procedure involved and no washing procedure involved (AC) was larger than zero for samples A to G. This interesting result showed that higher antimony concentration was detected in experiments with no washing procedures compared with those experiments with washing procedures. Our study results indicate that partial antimony leaching from PET bottles comes from contaminations on the surface of plastic during manufacturing process, while major antimony leaching comes from conditional changes.ConclusionThe results revealed that heating and microwaving enhance antimony leaching significantly in PET plastic bottles. Plastic bottle manufacturers should consider the contaminations during manufacturing process and washing bottles before first use was strongly recommended to remove those contaminants.

Rapid IC–ICP/MS method for simultaneous analysis of iodoacetic acids, bromoacetic acids, bromate, and other related halogenated compounds in water

Haloacetic acids (HAAs) and bromate are toxic water disinfection by-products (DBPs) that the U.S. Environmental Protection Agency has regulated in drinking water. Iodoacetic acids (IAAs) are the emerging DBPs that have been recently found in disinfected drinking waters with higher toxicity than their corresponding chloro- and bromo-acetic acids. This study has developed a new rapid and sensitive method for simultaneous analysis of six brominated and four iodinated acetic acids, bromate, iodate, bromide, and iodide using ion chromatography-inductively coupled plasma-mass spectrometry (IC-ICP-MS). Mono-, di- and tri-chloroacetic acids are not detected by this method because the sensitivity of ICP-MS analysis for chlorine is poor. Following IC separation, an Elan DRC-e ICP-MS was used for detection, with quantitation utilizing m/z of 79, 127, and 74 amu for Br, I, and Ge (optional internal standard) species, respectively. Although the primary method used was an external standard procedure, an internal standard method approach is discussed herein as well. Calibration and validation were done in a variety of natural and disinfection-treated water samples. The method detection limits (MDLs) in natural water ranged from 0.33 to 0.72 microg L(-1) for iodine species, and from 1.36 to 3.28 microg L(-1) for bromine species. Spiked recoveries were between 67% and 123%, while relative standard deviations ranged from 0.2% to 12.8% for replicate samples. This method was applied to detect the bromine and iodine species in drinking water, groundwater, surface water, and swimming pool water.

Determination of vitamin A in dried human blood spots by high-performance capillary electrophoresis with laser-excited fluorescence detection

We have developed a high-performance capillary electrophoresis (HPCE) method to analyze the retinol (vitamin A) concentration as retinol-retinol binding protein (holo-RBP) from microvolumes of serum (5-10 microliters) or one to two drops (approximately 20 microliters) of blood collected and air-dried on blood collection filter paper. A 0.64-cm diameter disk was cut from the dried whole blood specimens and the samples were dissolved in a pretreatment buffer and filtered. Filtrate was injected onto the HPCE column for analysis. The separation was carried out in a 60 cm x 50 microns I.D. fused-silica capillary and the running voltage was 20 kV. A He-Cd laser with a wavelength of 325 nm was used for excitation, and the fluorescence of the holo-RBP complex was monitored at 465 nm by a photodiode. A virtual linear relationship was obtained for the retinol concentrations between HPCE and HPLC for 28 serum samples, 19 dried venous blood samples and 9 capillary dried blood spot samples, indicating that valid measures of serum retinol can be obtained from one to two drops of capillary blood collected on filter paper. The absolute detection limit for retinol by HPCE is below 3 micrograms/l. The method is very useful for vitamin A level screening, especially for children and premature new-born babies.

Single particle ICP-MS characterization of titanium dioxide, silver, and gold nanoparticles during drinking water treatment.

One of the most direct means for human exposure to nanoparticles (NPs) released into the environment is drinking water. Therefore, it is critical to understand the occurrence and fate of NPs in drinking water systems. The objectives of this study were to develop rapid and reliable analytical methods and apply them to investigate the fate and transportation of NPs during drinking water treatments. Rapid single particle ICP-MS (SP-ICP-MS) methods were developed to characterize and quantify titanium-containing, titanium dioxide, silver, and gold NP concentration, size, size distribution, and dissolved metal element concentration in surface water and treated drinking water. The effectiveness of conventional drinking water treatments (including lime softening, alum coagulation, filtration, and disinfection) to remove NPs from surface water was evaluated using six-gang stirrer jar test simulations. The selected NPs were nearly completely (97 ± 3%) removed after lime softening and alum coagulation/activated carbon adsorption treatments. Additionally, source and drinking waters from three large drinking water treatment facilities utilizing similar treatments with the simulation test were collected and analyzed by the SP-ICP-MS methods. Ti-containing particles and dissolved Ti were present in the river water samples, but Ag and Au were not present. Treatments used at each drinking water treatment facility effectively removed over 93% of the Ti-containing particles and dissolved Ti from the source water.

Fast separation and quantification method for nitroguanidine and 2,4-dinitroanisole by ultrafast liquid chromatography-tandem mass spectrometry.

Explosives are now persistent environmental pollutants that are targets of remediation and monitoring in a wide array of environmental media. Nitroguanidine (NG) and 2,4-dinitroanisole (DNAN) are two insensitive energetic compounds recently used as munitions explosives. To protect our environment and human health, the levels of these compounds in soils and waters need to be monitored. However, no sensitive analytical methods, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS), have been developed for detecting these new compounds at trace levels and to be concurrently applied to monitor the common explosives. In general, the concentrations of explosives in either soil or water samples are very low and widely distributed. Therefore, a fast and sensitive method is required to monitor those compounds and increase our ability to find and address the threats they pose to human health and ecological receptors. In this study, a fast and sensitive analytical method has been developed to quantitatively determine NG and DNAN in soil, tap water, and river water by using ultrafast LC-MS/MS. To make this method a comprehensive analytical technique for other explosives as well, it has included other commonly used explosives in the method development, such as octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,3,5-trinitroper-hydro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), 2-amino-4,6-dinitrotoluene (ADNT), and pentaerythritol tetranitrate (PETN). The method detection limits (MDLs) of these compounds in soil ranged from 0.2 to 5 ppb, and a good linearity was obtained over a concentration range of 0.5-200 ppb. The recoveries of some compounds are equal to or better than the current EPA methods but with much higher sensitivities.

Release and Removal of Microcystins from Microcystis during Oxidative-, Physical- and UV-based Disinfection

Cyanotoxins released from cyanobacteria (or blue-green algae) pose an increasing public health risk worldwide. In this study, the release of the cyanotoxin microcystin, from Microcystis aeruginosa due to oxidative, ultraviolet (UV), and physical impacts during water treatment was studied. Additionally, the relative and absolute rates of chemical oxidation of the six microcystins were determined for selected oxidants. Cell viability was measured based on treatment dosage using a fluorescence method. The specific chemical oxidants studied were free chlorine ( HOCl/ OCl− ) , chlorine dioxide, ozone, permanganate, and monochloramine. UV energy was at 254 nm. For chemical oxidants and UV, the exposures or doses examined were selected based on typical disinfection dosages. Other treatments examined included low and high salinity, ultrasonics, and physical blending. Free chlorine, permanganate, chlorine dioxide, monochloramine, and ozone were observed to at least partially disinfect the cyanobacteria, while the ...