Monitoring of aromatic monosulfonic acids in coastal waters by ion-pair liquid chromatography followed by electrospray-mass spectrometric detection.

Spain is one of the European countries that still discharges untreated wastewaters and sewage sludge into the sea. Aromatic monosulfonated compounds were detected in 36 seawater samples collected bimonthly on the Catalonian coast (Spain) over a period of 18 months. These compounds are of environmental concern because of their limited biodegradability and high mobility within the aquatic system. A method based on a sequential solid-phase extraction procedure (SSPE) followed by ion-pair liquid chromatography coupled to electrospray ionization-mass spectrometry (IPC-ESI-MS) in negative ionization mode was used to monitor aromatic monosulfonated compounds in the Catalonian coastal waters. Triethylamine (TEA) and acetic acid (HOAc) were used as volatile mobile-phase additives. A comparison of two polymeric solid-phase extraction (SPE) materials for the extraction of 15 aromatic monosulfonated compounds of environmental concern was performed. The investigated adsorbents were the polystyrene-divinylbenzene materials Lichrolut EN, from Merck, and Isolute ENV+, from International Sorbent Technology (IST). The influence of the matrix on the analysis of seawater samples was also studied. Applications of the developed analytical procedure to seawater samples gave limits of detection (n = 3) ranging from 0.6 to 45 pg on column for the target analytes. Barcelona and Tarragona locations were chosen along the Catalonian coast as sampling sites because of their large sewage discharges and intensive industrial activities. Samples were acquired from submarine outfalls of two rivers, Besos and Llobregat, located in the north and south of Barcelona city, respectively. Samples from petrochemical industry submarine outfalls located near the commercial port of Tarragona were also studied. Concentrations of benzenesulfonates (BS) and naphthalenesulfonates (NS) were of the order of ng/ml. Most of the collected samples were found to contain both isomers of mononaphthalenesulfonate. The study showed that these compounds can contaminate marine coastal waters.