Application Note Environmental Mass Spectrometry Analysis of Hormones in Water by Direct Injection Using the Agilent 6470 Triple Quadrupole Mass Spectrometer Authors Abstract Imma Ferrer, E. Michael Thurman, and Some hormones are included in the Contaminant Candidate List CCL4 of the Jerry A. Zweigenbaum Environmental Protection Agency (EPA) to be assessed for regulation in drinking University of Colorado and water. These compounds are also of regulatory interest in the EU, China, and other Agilent Technologies, Inc. countries. Therefore, the environmental community often desires the analysis of these compounds in water samples. This Application Note describes the methodology used for the determination of eight hormones (17-α-ethinylestradiol, 17-β-estradiol, estriol, 4-androstene-3,17-dione, equilin, estrone, progesterone, and testosterone) in tap water using an Agilent 6470 triple quadrupole mass spectrometer. A direct injection method using 100 µL of water sample was carried out. This method saves time, reduces handling errors and analytical variability, and is sensitive enough to detect hormones in surface and drinking water at ng/L levels. Introduction Both positive and negative ion modes and stored at −18 °C. A mix of all were used, depending on the specific the hormones was prepared at a The presence of hormones in compound. We also used a novel concentration of 1 μg/mL. Serial dilutions environmental waters has always been mobile phase approach that included were prepared to obtain a calibration controversial because either none have ammonium fluoride to enhance the curve ranging from 1 to 500 ng/L. been detected, or very low traces have negative ion signal4. 1 Sample preparation been found in surface water systems . The work in this Application Note Tap water was chosen as a matrix Once the residual waters are treated was completed using an Agilent 1290 for building calibration curves. in wastewater treatment plants, these Infinity II UHPLC system consisting of a Laboratory-fortified samples were compounds adsorb to sludge and binary pump, autosampler, thermostatted prepared by adding known amounts sediments, and have removal rates of column compartment, and a 6470 triple 2 of the hormone mix to the water. up to 100 % . Their presence in drinking quadrupole LC/MS. water is unlikely. However, these Fortification levels for the target compounds have known endocrine Experimental hormones ranged from 1 to 500 ng/L in effects at sub-ng/L levels in water. tap water. As a result, they have always been Reagents and standards Instrument and operational included in regulatory environmental All target hormones were supplied by parameters protection lists, and there is a need for RESTEK (Bellefonte, PA). Ammonium This method was developed on an their determination in drinking water3. It fluoride was purchased from Agilent 1290 Infinity II LC with an is also possible that a regulatory action Sigma-Aldrich (St. Louis, MO). Reagent Infinity II multisampler, running an will be enacted to force water treatment grade methanol, acetonitrile, and Agilent InfinityLab Poroshell 120 EC-C18 facilities to look for these compounds in water were obtained from Burdick & column (p/n 693775-902). The LC raw and finished waters. Jackson (Muskegon, MI). Individual system was coupled to a 6470 triple Seven hormones (17-α-ethinylestradiol, hormone stock solutions (approximately quadrupole LC/MS. Table 1 lists the 17-β-estradiol, estriol, 4-androstene-3,17- 1,000 µg/mL) were prepared in pure instrument conditions chosen for the dione, equilin, estrone, and testosterone) acetonitrile or methanol, depending analysis of the eight hormones studied. were proposed for the third unregulated on the solubility of each compound, contaminant monitoring rule (UCMR3) under the EPA regulation of 2012. A Table 1. LC/MS/MS chromatographic and instrumental conditions used in this study. method (EPA 539) was published for their determination in drinking waters. LC conditions for the 1290 Infinity II LC This method used solid phase extraction Column InfinityLab Poroshell 120 EC-C18, 150 mm × 2.1 mm, 2.7 µm (p/n 693775-902) of a large volume of water (1 L), and Column temperature 25 ºC targeted LC/MS/MS detection. In Injection volume 100 µL 2016, a Contaminant Candidate List A) Acetonitrile Mobile phase B) 1 mM NH F in water (CCL4) was published, and only five 4 of the seven hormones were included Run time 11 minutes (17-α-ethinylestradiol, 17-β-estradiol, Flow rate 0.3 mL/min 30 % A at 0 minutes, gradient to 100 % A at 10 minutes, hold at 100 % A for 1 minute, estriol, equilin, and estrone). Gradient then 4 minutes post run time This Application Note develops a simple MS conditions with positive/negative switching and rapid methodology for the detection Sheath gas temperature 350 °C of eight hormones (17-α-ethinylestradiol, 17-β-estradiol, estriol, 4-androstene-3,17- Sheath gas flow 11 L/min dione, equilin, estrone, progesterone, and Gas temperature 250 °C testosterone) using a direct injection of Gas flow 10 L/min 100 µL of tap water. A multiple reaction Nebulizer pressure 45 psi monitoring targeted method was used Capillary voltage 3,000 V in both positive and negative for the detection of the hormones. Nozzle voltage 0 V in positive mode and 500 V in negative mode 2 Results and discussion Table 2. Names, CAS numbers, and chemical structures of the hormones studied. Analyte CAS Number Chemical structure Ionization requirements OH Table 2 shows the names, CAS numbers, H and chemical structures of the hormones 17-α-Ethinylestradiol 57-63-6 studied. The list includes eight hormones H H (seven from the UCMR3 list plus HO progesterone, an important endogenous HO female hormone). These eight compounds were tested in both positive and negative ion modes. Compounds 17-β-Estradiol 50-28-2 H with a keto group in the benzylic ring H H (4-androstene-3,17-dione, progesterone, HO and testosterone) tend to ionize better in O positive ion mode. In contrast, the rest of the compounds, with hydroxyl groups H in the benzylic ring, ionize in negative ion 4-Androstene-3,17-dione 63-05-8 mode. H H Hormones do not exhibit great sensitivity O under electrospray conditions compared O to other pharmaceuticals or pesticides. Since most of the hormones ionize in Equilin 474-86-2 negative ion mode, the deprotonation of the hydroxyl group is not favorable HO compared to other molecules that OH have stronger electronegative moieties OH in their chemical structures. For this H reason, ammonium fluoride was used Estriol 50-27-1 to enhance ionization in negative ion H H mode. It was found that a concentration HO of 1 mM in the aqueous mobile phase O enhanced the sensitivity of most of the hormones. H Estrone 53-16-7 H H HO O Progesterone 57-83-0 H H H O OH H Testosterone 58-22-0 H H O 3 Source parameter optimization 17-α-Ethinylestradiol Estriol The Source Optimizer tool was used 17-β-Estradiol Estrone to optimize all parameters (drying 4-Androstene-3,17-dione Progesterone A gas temperature and flow, sheath Capillary voltage optimization Equilin Testosterone gas temperature and flow, nebulizer 140 pressure, capillary voltage, and nozzle 120 voltage). From all the parameters, the ones with the most variability were 100 % the capillary voltage and the nozzle 80 voltage. Figure 1A shows the relative intensity versus the capillary voltage 60 values used. A base value of 2,500 V Relative signal 40 was chosen for the optimization of the capillary voltage. Hormones that ionize 20 in positive ion (4-androstene-3,17-dione, 0 progesterone, and testosterone) see an 1,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 increase in sensitivity from low capillary Capillary voltage (V) voltage values to approximately 3,000 V, then a decrease in signal is observed B Nozzle voltage optimization at higher voltage values. In contrast, 250 hormones that ionize in negative ion do not see much variability with the voltage used. Therefore, a compromise 200 value of 3,000 V was chosen for their determination in both positive and % 150 negative ion mode. Figure 1B shows the relative intensity versus the nozzle voltage values 100 used. A base value of 0 V was used Relative signal for the optimization. In this case, a dramatic drop in sensitivity occurred 50 when using higher nozzle voltages for hormones that ionize in positive ion 0 mode. Similarly to the capillary voltage, 0 500 1,000 1,500 2,000 2,500 not much variability was observed Nozzle voltage (V) for negative ion compounds. A slight increase in sensitivity was observed for Figure 1. Optimization of capillary voltage (A) and nozzle voltage (B) for the hormones studied in this work. 17-β-estradiol, estrone, and estriol at 500 V compared to 0 V. This value was chosen for negative ion mode conditions. 4 Analysis parameters Chromatographic separation in 10 minutes), while maintaining a The Optimizer tool was used to get the Separation of the hormones was reasonable analysis time. Figure 2 shows best fragmentor voltages and collision successfully achieved using a slow a chromatogram for the analysis of a energies for the target hormones gradient of acetonitrile (from 30 to 100 % 100 ng/L standard in tap water. studied. The precursor ion was always either the protonated or the deprotonated Table 3. dMRM analysis parameters for the target hormones. Cell acceleration voltage: 7 V; molecule. First, the optimal fragmentor Delta EMV: 200 for positive ion and 400 for negative ion. voltage for the largest production of precursor ion was found. Next, two Precursor Product Fragmentor Collision Retention product ions for each of the hormones Compound ion ions voltage (V) energy (V) time (min) Polarity 183 40 were obtained, and the collision energy 17-α-Ethinylestradiol 295.2 150 6.0 Negative 145 40 required to form the product ions were 183 45 17-β-Estradiol 271.2 160 5.5 Negative optimized.