lation of PestjcUles from Industrial

Chem. Anal. (Warsaw), 38, 297 ~1993)
On-Line Extraction Method fo.. th~,Js()lation
of PestjcUles from Industrial-Waste Water
by K. Pomorska
Department ofEnvironment Toxicology, The Witold Chodiko Institute ofRuralMedicine,
20-950Lublin, Poland
Key words: pesticides, waste water, extraction, gas chromatography
The aim of the study was to develop a simple methodology of sample preparation in
order to determine pesticides in idustrial waste water. The study was ordered by The
Chemical Plant "Organika-Azot" in Jaworzno. The method of direct extraction employed in this w~rk~and based on-literature and the author's own investig~tions, enables
to extract the majority of pesticides by using the system consisting of two solvents of
diffrent polarity [1, 2]. The extraction is performed in one vessel and lasts 3-5 minutes.
The on-line extractionmethod is based on salting out effect by the addition of electrolyte
to the extracted ~fxture in order to release pesticides into the organic phase. The
extraction of the examined sample and following stages are combined into one process.
The obtained extra~t is dried with Na2S04, and concentrated to the volume of 1 ml.
Finally, the extract is analysed by gas chromatography method.
Celem badari bylo opracowanie prostej metodyki przygotowania probkiscieku przemyslowego do oznaczania pestycydow, Praca zostalawykonana na zamowienie Zakadow
Chemicznych "Organika-Azot" w Jaworznie. Na podstawie rozeznania literaturowego
oraz badari wlasnych wybrano metode bezposredniej ekstrakcji, umozliwiajaca wyizolowanie wiekszosci pestycydow za pomoca ukladu dwoch rozpusz~lni,k6w·orainej
polarnosci [1,2]. Ekstrakcja w tej metodzie przeprowadzana jest w jednym naczyniu, a
jej.czas trwania wynosi 3-5 min.
Podstawa metody bezposredniej ekstrakcji jest wykorzystanie efektu wysalania przez
dodanie elektrolitu do mieszaniny ekstrahowanej w celu wydzielenia pestycydow do
fazy organicznej. Ekstrakcja badanej probki i poszczegolne etapy rozdzialu polaczone
s~ w jeden proces. Otrzymanyekstrakt osuszany jest za pomoca Na2S04 i nastepnie
zatezany do okreslonej objetoaci, a nastepnie analizowany metoda chromatografii
gazowej.
298
Ki Pomorska
EXPERIMENTAL
Reagents and solvents
Acetone p.a. (POCh, Gliwice), nitrogen 99.985 % from gas cylinder, hexane p.a. (Reachim, USRR),
anhydrous sodium sulfate p.a. (POCh, Gliwice) roasted before use at 450°C for 4 h, sodium chloride
p.a , (POCh, Gliwice), Florisil60-1oo mesh (MERCK) heated in 130°C for 1 h, chloroorganic pesticides
standards (IPO, Warszawa) in hexane in concentration 0.00012 mg ml- l (y-HCH), 0.00084 mg ml-1
(pp'DDT), 0.0027 mg ml- l (pp'DMDl).
Apparatus
Gas chromatograph Pye-Unicam series 104 with ECD-Ni 63 detector and glass column (length 1.5
m, inside diameter 0:4 em) filled with liquid stationary phase SE':'30 in the amount of 3 %(m/m) on
Diatomite CQ (Pye-Unicam) of particle size distribution 100-120 mesh, vacuum evaporator (Unipam).
Chromatographic determination conditions: detector temperature 250°C, column temperature
190°C, feeder temperature 230°C, attenuation 20x10 2, carrying nitrogen gas flow 60 ml min-I. Figure
1 presents chromatogram of the standard mixture .
3
2
tr,min
Figure 1. Chromatogram of standard mixture of chlorinated hydrocarbons. GC parameters: detector
(ECD), 1.5 m glass column (0.4 em i. d.) packed with 3 % SE-30 on Diatomite CQ 80-100
mesh operated at 190°C, with carrier gas (N2) flow rate 60 ml min"! and detector temperature
of 250°C: 1) 0.00012 fAog y-HCH; 2) 0.00085 fAog pp'DDT; 3) 0.0027 fAog pp'DMDT
Analytical procedure
The investigated material was 100 ml waste water sample . The following agents were subsequently
added: 200 ml acetone, about 30 g sodium chloride, 150 ml hexane. Then, the mixture was well shaken
for three to five minutes. After layer separation 200 ml of the solvent layer was collected. This layer
was shaken with 10 g of sodium sulfate. The obtained extract was evaporated in temperature 50°C to
the volume of 1 ml and then it was analysed by gas chromatography method.
Extraction ofpesticidesfrom .w.aste water
299
Pesticides concentration in the samplewas.calculated according-to the following formula:
,.
x-
m~:::X:ea::
'l l1g 1-1] " .
where m is the pesticides mass (l1g) determined in 200 ml extract evaporated to 1 ml, 1.75 - a coefficient
resulting fromextract volume sampled for determination.
. Recovery test
The method recovery test-was carried out for the following compounds: y-HCH,
pp'DDT and pp'DMDT. Table 1 presents pesticides recovery from waste water
samples enriched with pesticides.
Table 1. Recovery of chlorinatedhydrocarbons from waste water samples enriched with pesticiJ~ (with.
out cleaning-up process)
.
Amount of substance added to the sample
I1g
Recovery
%
y-HCH
pp'DDT
pp'DMDT
y·HCH
pp'DDT
pp'DMDT
0.240
1.70
5.40
58.53
83.07
87.50
0.240
1.70
5040
60.20
73.88
87.50
.0·240
0.120
1.70
5,40
60.20
97.22
98.43
2.70
70.01
72.91
76.60
x=62.23
x =81.07
s=5.24
s= 11.27
;
0.85
x
=87.53
s = 8.91
In case where the obtained extract was coloured yellow or cloudy an additional
cleaning was applied in column filled with 3;g of Florisil. Table 2 presents recovery
results from cleaned extracts.
Table 2. Recovery ~(cWorinated hydrocarbons from waste ~ater samples enriched with pesticides (with
cleaning-up process)
..
, ,
Amount of substance added to,the sample
~' ~
c l1g
y-HCH
pp':PD.T
I'
"
~
.1 pp'DMDT
;.
1.70
0.240
1.70
5040
70.07
,
71.53
0.240
1.70
5.40
67.88
0.240
1.70
5.40
71.00.
5040
•
pp'DDT
pp'DMDT
87.62
80.31
'81.#;'
82.30
-. -:
y'~HCH "
"
0.240
Recovery
%
'.
87.62
71.10
102.06
67.20
x=70.12
x =89.66
x=75.22
s = 1.61
s=8.78
s =7.24
Relative error: y-HCH2.29 %; pp'DDT 9.79 %;pp'DMDT 9.62~.
c.
K.Pomorska
300
The presented method was applied for the determination of chloroorganic
pesticides in waste water sampled in the area of The Chemical Plant "Organika-Azot"
in Jaworzno. Table 3 presents the results of the determinations.
Table 3. Results of chlorinated hydrocarbons determinations in waste water samples from The Chemical
Plant "Organika Azot" Jaworzno
Concentrations of chlorinated hydrocarbons, ~g
Samples collection place
r'
y-HCH
pp'DDT
pp'DDT
1.810
2.009
13.700
Pool water collected
over the sediment
Meliorative pit
Waste water from field "K"
River water
2.980
16.420
6.930
21.010
41.290
32.470
1.781
3.490
below
detection
limit
Well water sampled
not detected
not detected
in the Plant's area
not detected
Figure 2 shows an exemplary chromatogram of the sample from the waste water.
oJ
bJ
2
13
2
20
13
2
Figure Z. Chromatograms of waste water extracts: a) waste water from field "K", b) water sample from
the river crossing the Plant's area: 1- y-HCH, 2 - pp'DDT, 3 - pp'DMDT
Calculated limit of detection for individual compounds was: y-HCH - 0.52 flg 1-1 ,
pp'DDT-2.67 flg 1-1, pp'DMDT-l1.81 J.lg 1-1.
Extraction ofpesticides from waste water
301
Conclusions
A simple method for the determination of pesticides in waste water was devised.
The method consists in solvent extraction followed by concentration by evaporation
to a small volume followed by quantitative determination by gas chromatography.
The recoveries of individual compounds ranged from 70.1 to 89.6 % and the limits
of detection were of the order of a few Jlg 1:"1.
REFERENCES
1. Steinwandter H.,AnalyticaIMethodsforPesticides andPlantGrowthRegulators.AnalyticalTechniques,
Ed. Sherma J., Academic Press, Inc., San Diego, california 1989, Vol. 17, p, 56.
2. Steinwandter H., Fresenius Z. Anal. Chem., 32Z, 752 (1985).
Received June 1992
AcceptedDecember 1992