Rapid analysis of iodinated X-ray contrast media in secondary and tertiary treated wastewater by direct injection liquid chromatography-tandem mass spectrometry

Abstract

The iodinated X-ray contrast media are the most widely administered intravascular pharmaceuticals and are known to persist in the aquatic environment. A rapid method using direct injection liquid chromatography-tandem mass spectrometry (DI-LC-MS/MS) has been developed to measure eight ICM. These include iopamidol, iothalamic acid, diatrizoic acid, iohexol, iomeprol, iopromide, plus both ioxaglic acid and iodipamide, which have not previously reported in the literature. The LC-MS/MS fragmentation patterns obtained for each of the compounds are discussed and the fragments lost for each transition are identified. Matrix effects in post-RO water, MQ water, tap water and secondary effluent have also been investigated. The DI-LC-MS/MS method was validated on both secondary and tertiary treated wastewater, and applied to samples from an advanced activated sludge wastewater treatment plant (WWTP) and a water recycling facility using microfiltration (MF) and reverse osmosis (RO) in Perth, Western Australia. As well as providing information of the efficacy for RO to remove specific ICM, these results also represent the first values of ICM published in the literature for Australia.

Ecotoxicological aspects related to the presence of pharmaceuticals in the aquatic environment

“…Iopromide Groundwater Australia 0.577 [200] Algae S. subspicatus [158] >10.0 g L [201] Iopromide Germany SPE-HPLC-MS/MS SPE-HPLC-MS 40 [202] Iopromide Germany 50 1600 <50 [203] >1.0 g L…”

“…Contam-ination by X-ray contrast media has been reported in different aquatic environments (Table 9). Media have been detected in STP influents and effluents [198][199][200][201], surface waters [199,[201][202][203], groundwaters [26,199,200] and even drinking water [200,202,203] at concentrations that can reach few µg L −1 . Although accepting that X-ray contrast media do not exhibit toxic effects at high con-centration levels, additional studies should be undertaken with a view to evaluating chronic effects, due to continuous exposure of aquatic organisms to these pharmaceuticals.…”

Trace analysis of environmental matrices by large-volume injection and liquid chromatography–mass spectrometry

“…Therefore, the 'tools' that are used to address matrix effects are the same for both approaches and include 1) tunable LC gradients for on-line clean-up [35,41,52]; 2) deuterated standards [43] 3) standard addition and matrix-matched calibration curves [25,43,47]; 4) sample dilution [60]. Although matrix effects are compound and sample dependent, it has been shown to be moderate to minimal for SC-LVI [25,45,47].…”

“…Samples to be injected by SC-LVI onto enrichment/separation columns still must be as particle free as possible to avoid plugging the system. Filtration is commonly used [23,25,26,37,45,47,48]. Centrifugation is simple, requires no specialized training, uses common equipment, generates no solid waste and samples can be treated in batches [35,41,52].…”

“…With the advent of commercialized mass spectrometers fitted with multiple stage vacuum systems and with more efficient atmospheric pressure ionization (API) sources, higher LC flow rates, larger column diameters and larger injection volumes were made possible. An increasing number of publications have since appeared in the scientific literature that describe SC-LVI for use with mass spectrometry for the determination of pesticides in vegetables [20], water [21][22][23][24][25][26][27][28][29], and soil [30][31][32][33]; fluorochemicals in wastewater, groundwater and surface water [33][34][35][36][37]; neurotoxins in surface water, groundwater and drinking water [38,39]; pharmaceuticals (legal and/or illicit) in surface, ground, and waste water [25,33,[40][41][42][43][44]; corrosion inhibitors in surface, ground, and waste water [33,45]; chelating agents in surface, drinking, and waste water [46]; iodinated chemicals in waste water and treated water [47][48][49]; artificial sweeteners in ground, waste, and treated water [50]; biocides in surface and waste water [51]; bisphenol A in soil [33]; steroids in waste water [52]; and surfactants in seawater (unpublished) ( Table 2). The success and popularity of SC-LVI compared to ON-E and CC-LVI are most likely due to its sim...…”