Supplementary Materials Low-Cost Quantitation of Multiple Volatile Organic Compounds in Air Using Solid-Phase Microextraction
Olga P. Ibragimova, Nassiba Baimatova and Bulat Kenessov *
Center of Physical Chemical Methods of Research and Analysis, Al-Farabi Kazakh National University, Almaty 050012, Kazakhstan; [email protected] (O.P.I.), [email protected] (N.B.) * Correspondence: [email protected] (B.K.); Tel.: +7-727-2390624
Table S1. The list of chosen VOCs and its physical properties.
Purity Molar mass Boiling Compound Origin CAS No. (%) (g mol−1) Point (°C) 2,2,4- Sigma-Aldrich ≥99.5 540-84-1 114.2 99 Trimethylpentane (St. Louis, MO, USA) n-Heptane ≥99.0 142-82-5 100.2 98 Reachem LLO Methyl ethyl ketone 78-93-3 72.11 80 ≥98.0 (Moscow, Russia) Methylene chloride 75-09-2 84.93 40 Benzene ≥99.8 EKOS-1 LLP 71-43-2 78.11 80 n-Decane ≥99.5 (Moscow, Russia) 124-18-5 142.3 174 1,1,2,2- Sigma-Aldrich ≥99.5 127-18-4 165.8 121 Tetrachloroethylene (St. Louis, MO, USA) EKOS-1 LLP Toluene ≥99.8 108-88-3 92.14 111 (Moscow, Russia) Component-reactive LLO 1,2-Dichloroethane ≥99.0 107-06-2 98.96 83 (Moscow, Russia) LLO Ekroschem n-Undecane ≥99.0 1120-21-4 156.3 196 (St. Petersburg, Russia) Ethylbenzene 100-41-4 106.2 136 m-Xylene ≥99.0 108-38-3 106.2 139 p-Xylene Sigma-Aldrich 106-42-3 106.2 138 Propylbenzene ≥98.0 (St. Louis, MO, USA) 103-65-1 120.2 159 o-Xylene ≥99.0 95-47-6 106.2 144 Chlorobenzene ≥99.5 108-90-7 112.6 132 1,3,5- LLO Ekroschem ≥99.0 108-67-8 120.2 165 Trimethylbenzene (St. Petersburg, Russia) 1,2,4- Topan LLP (Uralsk, ≥98.0 95-63-6 120.2 169 Trimethylbenzene Kazakhstan) Sigma-Aldrich 3-Picoline ≥99.0 108-99-6 93.13 144 (St. Louis, MO, USA) Chemregion LLO Benzaldehyde ≥98.0 (Nizhniy Novgorod, 100-52-7 106.1 178 Russia) n-Hexadecane ≥99.0 Sigma-Aldrich 544-76-3 226.4 287 Naphthalene ≥99.0 (St. Louis, MO, USA) 91-20-3 128.2 218 Thermo Fisher Scientific Phenol ≥99.5 108-95-2 94.11 182 (Waltham, MA, USA) Acenaphthene ≥99.0 Sigma-Aldrich 83-32-9 154.2 279 Fluorene ≥98.0 (St. Louis, MO, USA) 86-73-7 166.2 295
Separations 2019, 6, 51; doi:10.3390/separations6040051 www.mdpi.com/journal/Separations Separations 2019, 6, 51 2 of 5
Table S2. Coordinates of sampling locations.
Code Crossroad Coordinates Elevation (m) P1 Radostovets st. – al-Farabi av. N43°12.007', E76°53.774' 978
P2 Mendikulov st. – al-Farabi av. N43°13.654', E76°57.252' 944
P3 Nauryzbay Batyr st. – Raiymbek av. N43°16.099', E76°56.062' 764
P4 Papanin st. – Suyunbay av. N43°19.095', E76°57.781' 700
P5 Raiymbek av. – Akhrimenko st. N43°14.950', E76° 50.844' 770
P6 Shevchenko st. – Gagarin av. N43°14.612', E76°53.586' 803
Table S3. Weather conditions on sampling days. Temperature Wind Velocity Pressure Humidity Sampling Date (℃) (m s−1) (mmHg) (%) (weather) 8:00 8:00 8:00 8:00 8:00 8:00 8:00 8:00 AM PM AM PM AM PM AM PM 03/30/19 (rainy) 9 11 0.7 0.3 692 694 80 67 04/02/19 (cloudy) 10 6 1 1 693 696 75 95 04/04/19 (cloudy) 16 14 1 1 692 693 69 77 Separations 2019, 6, 51 3 of 5
Table S4. Probabilities of difference between initial responses of analytes and their responses after different storage times.
Storage time, h Analyte 0–8 0–16 0–24 0–36 0–48 P values 2,2,4-Trimethylpentane 0.14 0.47 0.44 0.19 0.30 n-Heptane 0.16 0.49 0.43 0.16 0.29 Methyl ethyl ketone 0.16 0.28 0.11 0.13 0.16 Methylene chloride 0.80 0.89 0.71 0.30 0.87 Benzene 0.57 0.94 0.68 0.40 0.90 n-Decane 0.19 0.20 0.18 0.18 0.18 1,1,2,2-Tetrachloroethylene 0.55 0.95 0.62 0.47 0.85 Toluene 1.00 0.78 0.47 0.30 0.38 1,2-Dichloroethane 0.16 0.30 0.63 0.23 0.95 n-Undecane 0.05 0.03 0.02 0.02 0.01 Ethylbenzene 0.95 0.91 0.47 0.34 0.77 m-Xylene 0.87 0.96 0.44 0.37 0.72 p-Xylene 0.93 0.74 0.43 0.48 0.73 Propylbenzene 0.82 0.79 0.66 0.46 0.55 o-Xylene 0.96 0.66 0.77 0.65 0.84 Chlorobenzene 0.90 0.42 0.92 0.97 0.90 1,3,5-Trimethylbenzene 0.80 0.39 0.76 0.83 0.56 1,2,4-Trimethylbenzene 0.76 0.37 0.90 0.57 0.29 3-Picoline 0.83 0.31 0.14 0.30 0.15 Benzaldehyde 0.83 0.37 0.92 0.37 0.29 n-Hexadecane 0.17 0.29 0.27 0.04 0.03 Naphthalene 0.18 0.08 0.07 0.04 0.05 Phenol 0.50 0.93 0.67 0.63 0.39 Acenaphthene 0.17 0.06 0.05 0.03 0.02 Fluorene 0.11 0.04 0.03 0.02 0.01 Number of analytes, responses of which were significantly different from 1 2 3 5 5 initial values at p < 0.05 and RSD = 10% Separations 2019, 6, 51 4 of 5
Table S5. Sampling locations where lowest and highest concentrations of analytes were determined at different sampling times.
Locations where lowest/highest concentrations were determined Sampling date >> Saturday, March 30 Tuesday, April 2 Thursday, April 4 Analyte 8 AM 8 PM 8 AM 8 PM 8 AM 8 PM 2,2,4-Trimethylpentane P2/P3 P4/P3 P1/P3 P2/P5 P2/P4 P2/P5 n-Heptane P2/P3 P5/P3 P1/P3 P1/P5 P1/P4 P4/P5 Methyl ethyl ketone n/d n/d n/d n/d n/d n/d Methylene chloride P4/P3 P1/P5 P3/P2 P1/P2 P2/P4 P6/P2 Benzene P1/P3 P1/P3 P1/P3 P3/P4 P1/P3 P2/P6 n-Decane P5/P1 P5/P6 P2/P6 P5/P2 P2/P4 P4/P3 1,1,2,2-Tetrachloroethylene P4/P1 P6/P2 P1/P2 P1/P3 P1/P3 P1/P6 Toluene P1/P3 P1/P5 P1/P3 P6/P4 P2/P4 P4/P5 1,2-Dichloroethane n/d n/d n/d n/d n/d n/d n-Undecane P5/P4 P3/P2 P2/P6 P4/P2 P2/P4 P6/P5 Ethylbenzene P2/P5 P2/P5 P2/P3 P6/P5 P1/P4 P4/P3 m-Xylene P2/P4 P1/P5 P1/P3 P6/P5 P2/P4 P4/P5 p-Xylene P1/P3 P1/P5 P1/P3 P6/P5 P1/P4 P1/P3 Propylbenzene P1/P3 P2/P5 P1/P3 P1/P5 P6/P4 P4/P1 o-Xylene P1/P3 P1/P5 P1/P3 P1/P5 P1/P3 P4/P5 Chlorobenzene P1/P3 P2/P5 P1/P3 P6/P5 P2/P4 P1/P3 1,3,5-Trimethylbenzene P1/P3 P2/P5 P1/P3 P1/P5 P1/P4 P1/P6 1,2,4-Trimethylbenzene P2/P5 P2/P5 P2/P5 P1/P5 P2/P5 P1/P3 3-Picoline P1/P3 P2/P1 P1/P3 P5/P6 P1/P4 P1/P3 Benzaldehyde P3/P2 P1/P4 P2/P5 P5/P6 P3/P5 P4/P3 n-Hexadecane P5/P2 P2/P3 P5/P2 P4/P6 P5/P3 P3/P2 Naphthalene P4/P2 P3/P4 P6/P3 P1/P4 P6/P5 P1/P3 Phenol P6/P3 P1/P4 P1/P3 P3/P4 P1/P3 P1/P2 Acenaphthene P5/P4 P3/P4 P5/P2 P3/P4 P5/P3 P1/P3 Fluorene P5/P2 P3/P2 P3/P5 P2/P4 P3/P5 P1/P2 Note: n/d – not detected
Separations 2019, 6, 51 5 of 5
Figure S1. Chromatogram obtained using the developed method based on SPME-GC-MS of air sample with Cadd = 100 µg m-3. Column: DB-WAXetr (60 m × 0.25 mm × 0.50 µm). Oven program: initial 35 °C (held for 5 min) to 150 °C (held for 5 min) at the heating rate of 10 °C min−1, then to 250 °C (held for 7 min) at the heating rate of 10 °C min−1.
Figure S2. Effect of desorption time on responses of analytes: (a)—2,2,4-trimethylpentane, 1,1,2,2- tetrachloroethylene, chlorobenzene, methyl ethyl ketone, 1,2-dichloroethane; (b)—benzene, toluene, ethylbenzene, m,p,o-xylenes, propylbenzene, n-hexadecane; (c)—n-heptane, methylene chloride, n- decane, n-undecane, 3-picoline, benzaldehyde, and (d)—1,3,5-trimethylbenzene, naphthalene, acenaphthene, 1,2,4-trimethylbenzene, phenol, fluorene.