Sensitive determination of salicylate and benzophenone type UV filters in water samples using solid-phase microextraction, derivatization and gas chromatography tandem mass spectrometry.
A sensitive procedure for the determination of three UV filters: ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (Homosalate, HMS), 2-hydroxy-4-methoxybenzophenone (BP-3) and two related hydroxylated benzophenones (2,4-dihydroxybenzophenone, BP-1 and 2,2'-dihydroxy-4-methoxybenzophenone, BP-8) in water samples is presented. Analytes were first concentrated on the coating of a solid-phase microextraction (SPME) fibre, on-fibre silylated and then determined using gas chromatography combined with tandem mass spectrometry (GC-MS/MS). Factors affecting the performance of extraction and derivatization steps are thoroughly evaluated and their effects on the yield of the sample preparation discussed. Under final working conditions, a PDMS-DVB coated SPME fibre was exposed directly to 10 mL of water, adjusted at pH 3, for 30 min. After that, the fibre was placed in the headspace (HS) of a 1.5 mL vial containing 20 microL of N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA). On-fibre silylation of hydroxyl groups contained in the structure of target compounds was performed at 45 degrees C for 10 min. The whole sample preparation process was completed in 40 min, providing limits of quantification from 0.5 to 10 ng L(-1) and acceptable precision (RSDs under 13%) for samples spiked at different concentrations. All compounds could be accurately determined in river and treated wastewater (relative recoveries from 89 to 115%) using standards in ultrapure water, whereas standard addition is recommended to quantify their levels in untreated wastewater. Analysis of wastewater revealed the systematic presence of BP-3 and BP-1 in raw samples with maximum concentrations close to 500 and 250 ng L(-1), respectively.
Negreira
N
N
Departamento de Química Analítica, Nutrición y Bromatología, Instituto de Investigación y Análisis Alimentario, Universidad de Santiago de Compostela, Santiago de Compostela 15782, Spain.
Rodríguez
I
I
Ramil
M
M
Rubí
E
E
Cela
R
R
D001577:Benzophenones / Q000032:analysis* / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry; D015203:Reproducibility of Results; D045483:Rivers; D012459:Salicylates / Q000032:analysis* / Q000302:isolation & purification; D052617:Solid Phase Microextraction / Q000379:methods*; D013473:Sunscreening Agents / Q000032:analysis* / Q000302:isolation & purification; D053719:Tandem Mass Spectrometry; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification
D001577:Benzophenones; D012459:Salicylates; D013473:Sunscreening Agents; D014874:Water Pollutants, Chemical; D014867:Water; C103422:2-ethylhexyl salicylate; C005290:oxybenzone; C004839:dioxybenzone; C121479:2,4-dihydroxybenzophenone; C060446:homosalate