SAMPLE PREPARATION Despite the tremendous growth during recent years in number of work dealing with
7.2 SAMPLE PREPARATION Despite the tremendous growth during recent years in number of work dealing with
the determination of the pesticide levels in various food of animal origin, no standard analytical procedures have yet been set for these compounds. This has resulted in a variety of analytical approaches for both sample preparation and instrumental analysis. Because of the low levels at which these compounds may be present in complex animal matrices, sample treatments include a number of steps for exhaustive extrac- tion and preconcentration of the target compounds, followed by purification before final chromatographic separation and detection. In most instances, the need for additional fractionation usually depends on the selected chromatographic and detec- tion systems and=or on the specific study goal. Tables 7.1 and 7.2 summarize relevant data on selected analytical procedures used for the determination of pesti- cides in a wide variety of food samples of animal origin. Furthermore, due to
180 TABLE 7.1
Overview of Typical Analytical Procedures Used for the Determination of Pesticides by GC-MS or LC-MS Techniques in Food of Animal Origin
Recovery Pesticide
Sample Type
(%) References 368 Multiclass
Tissues of beef,
40 –120 [2] Analysis mutton, chicken,
Blender homogenization
GPC
DB-1701 (30 m 3
GC-MS (SIM)
Cyclohex:EtOAc (1:1)
0.25 mm 3 0.25 mm)
LC-MS=MS
pork, and rabbit
dC 18 (150 mm 3
of 69 Multiclass Pesticides Atrazine
2.1 mm 3 3 mm)
Beef kidney (0.5)
MSPD (XAD-7 HP) þ PLE
DB-5 (30 m 3
GC-MS (SIM)
(EtOH:water) þ SPME
0.25 mm 3 0.10 mm)
OCs þ Py Ground beef (100)
Isooctane-ACN partition
Florisil
DB-5 (30 m 3
GC-IT-EI-MS
in OCs, OPs
0.25 mm 3 0.25 mm)
(SIM)
Muscle of chicken,
70 –90 [5] Food pork, and lamb (5)
Polytron (Na 2 SO 4 þ EtOAc)
GPC
VF-5MS (30 m 3
GC-EI-MS=MS
0.25 mm 3 0.25 mm)
OCs, OPs Liver of chicken,
70 –115 [6] and pork, and lamb (5)
Polytron (Na 2 SO 4 þ EtOAc)
GPC
VF-5MS (30 m 3
GC-EI-MS=MS
0.25 mm 3 0.25 mm)
Benomyl Goat liver (5)
— [7] Environmental metabolites
Raney Ni reduction þ acidic
SB-PH (150 mm 3
LC-TSP-
dehydration þ defatting þ
4.6 mm) þ SB-PH
MS=MS
EtOAc
(250 mm 3 4.6 mm)
Carbamates Beef and chicken
19 –146 [8] tissues (5)
SFE (CO 2 )
SB-PH-30 (1.5 m 3
SFC-MS (SIM)
0.1 mm þ 0.25 mm)
OCs Pork fat (1.25)
EtOAc:Cyclohex 1:1
GPC
VF-5MS (30 m 3
GC-EI-MS=MS
Samples Triazine
0.25 mm 3 0.25 mm)
57 –107 [10] herbicides
Bovine milk (50)
HFM-SPME
DB-5 (30 m 3
GC-MS (SIM)
0.32 mm 3 0.25 mm)
Determination 40 Multiclass
Milk (whole or
81 –110 [11] powdered) (1)
Formic acid þ TEA þ Shake
CP-Sil 8 (10 m 3
LP-GC-EI-
(water) þ SPME (PDMS-
0.53 mm 3 0.25 mm)
MS=MS
DVB)
Carbamates Bovine milk (3)
MSPD (sand) þ hot water
Alltima C 18 (250 mm 3
LC-ESI-MS=MS
(pH ¼ 4.6) extraction
4.6 mm 3 5 mm)
(SIM)
Herbicides and Bovine milk (4)
85 –102 [13] of fungicides
Carbograph 4 þ back-flushing
Alltima C 18 (250 mm 3
LC-ESI-MS=MS
Pesticides OCs
with MeOH and DCM
Acidified
CP Sil 8 (50 m 3
GC-MS (SIM)
n.r. [14]
silica (Hex) þ
0.25 mm)
activated silica (Hex:DCM 1:1)
in OCs
Eggs (2 –5)
Shake (MeOH), sonication
Fractionation by
DB-XLB (60 m 3
GC-MS (SIM)
51 –108 [15] Food
(Hex, Na 2 SO 4 )
HPLC
0.25 mm 3 0.25 mm)
OCs, OPs, Py, Honey (10)
76 –119 [16] of ONs
Shake (water) þ EtOAc
Florisil (Hex:
LM-5 (35 m 3
GC-MS (SIM)
Animal OCs, OPs,
extraction
EtOAc 1:1)
0.25 mm 3 0.25 mm)
75 –107 [17] triazines
Honey (10)
Shake (water:MeOH, 70:30)
ZB-5MS (30 m 3
GC-MS (SIM)
þ SPE C 18 (Hex:EtOAc 1:1)
0.25 mm 3 0.25 mm)
51 Multiclass Honey (10)
Shake (water:MeOH, 70:30)
ZB-5MS (30 m 3
GC-MS (SIM)
86 –101 Origin [18]
þ SPE C 18 (Hex:EtOAc 1:1)
0.25 mm 3 0.25 mm)
OCs, OPs,
75 –94 [19] Py, ON
Honey (10 a ,5 b )
a Shake (water) þ Hex:Acet
Florisil (DCM:
LM-5 (35 m 3
GC-EI-MS
(60:40), b shake (water,
Hex 8:2 þ Hex:
0.25 mm 3 0.25 mm)
(SIM)
408C) þ SFE (CO 2 with
Act 6:4)
10% AcN)
OCs Honey (5)
Shake (water) þ SPE C 18 —
DB-5 (30 m 3
GC-MS (SIM)
(EtOAc þ MeOH þ DCM)
0.25 mm 3 0.25 mm)
Fluvalinate Honey (5 –10)
Shake (water:MeOH, 2:8) þ
C 18 cartridge
SE-54 (12 m 3
GC-MS (SIM)
EtOAc extraction
(Hex, 8 mL)
0.20 mm 3 0.30 mm)
14 Multiclass Honey (0.5)
Shake (water) þ SPME
RTX-5MS (30 m 3
0.25 mm 3 0.25 mm)
(SIM)
181 (continued )
182 TABLE 7.1 (continued)
Overview of Typical Analytical Procedures Used for the Determination of Pesticides by GC-MS or LC-MS Techniques in Food of Animal Origin
Recovery Pesticide
Sample Type
(%) References Chlordimeform
n.r. [23] Analysis and degrad-
Honey (1)
Shake (water) þ Hex:Acet
DB-17 (30 m 3
GC-EI-MS
8:2, extraction
0.25 mm 3 0.25 mm)
(SIM)
ation products Vinclozolin
Honey (1)
Shake (water) þ a Hex:Acet
a Florisil (Hex:
DB-17 (30 m
7:3, extraction, SPE C 18 DCM 1:1 v=v)
3 0.25 mm 3 0.25 mm)
Several Honey (1)
74 –96 [25] pesticides
Shake (water) þ SPE C 18 —
BP-1 (12 m 3
GC-EI-MS
(Hex:DCM 1:1)
0.22 mm 3 0.25 mm)
(SIM)
OCs Honey (10)
Shake (water) þ PE:EtOAc
Florisil (20% DE
DB-5 (30 m 3
GC-full-scan-
78 –108 [26] in
Food Triazole
8:2 extraction
in Hex)
0.25 mm 3 0.25 mm)
Hydromatrix þ Soxhlet (DE)
GPC þ Florisil
DB-5MS (30 m 3
GC-EI-MS=MS
and OPs
0.25 mm 3 0.25 mm)
Honey (0.5)
MSPD (C 18 )
Florisil (DCM:
Spherisorb C 18 (150 mm
OPs Honey (2.5)
Shake (water) þ SPME
Luna C 18 (250 mm 3
b Shake (water) þ SBSE
b 40 (PDMS) –66
OCs Fish (10)
Ultrasonic (Acet:Hex 5:2)
Cool extracts
DB-5 (30 m 3
GC-EI-MS
( 248C), Florisil
0.25 mm 3 0.25 mm)
(SIM)
Samples
(Acet:Hex 1:9, 13 mL)
Determination OCs
Fish (1 –10), fish
75 –90 [31] liver (0.50)
Soxhlet (Hex:Acet 3:1)
Acidified silica
HT-8 (25 m 3
GC-ECNI-MS
(Hex þ DCM)
0.22 mm 3 0.25 mm)
(SIM)
OCs Fish (5 –10)
Soxhlet (PE)
Sulfuric acid in
ZB-5 (30 m 3
GC-MS (SIM)
n.r. [32]
Hex þ silica
0.25 mm 3 0.25 mm)
column with
of OCs and
Na 2 SO 4
n.r. [33] Pesticides fipronil
Fish (10 –12)
Polytron (DCM:Hex 1:1)
GPC
BGB-172 Chiral
GC-MS (SIM)
column (30 m)
OCs Fish (2)
Soxhlet (Hex:Acet 3:1,
a Acidified silica
HP-5 (30 m 3
(Hex:DCM 3:1)
0.25 mm 3 0.25 mm)
(SIM)
b Alumina þ silica
in
Food OCs
þ Florisil
Fish (10), fish
72 –80 [35,36] liver (5)
Soxhlet (Hex:DCM:Acet
Acid silica þ
HT-8 (50 m 3
GC-EI-MS
neutral silica þ
0.22 mm 3 0.25 mm)
(SIM), GC-
of
deactivated basic
ECNI-MS
Animal
silica (Hex)
(SIM)
OCs Fish=shellfish (1)
Al 2 O 3 -activated basic þ
HP-5 (30 m 3
GC-EI-MS=MS
acidic silica gel þ SFE
0.25 mm 3 0.25 mm)
Origin
(CO 2 ) þ SPME (PDMS)
OCs Shellfish (1)
Al 2 O 3 -activated basic þ
HP-5 (30 m 3
GC-EI-MS=MS
acidic silica gel þ SFE
0.25 mm 3 0.25 mm)
(CO 2 )
OCs Fish (8)
Na 2 SO 4 þ Hex extraction
NPLC
DB-5 (30 m 3
GC-EI-MS=MS
0.25 mm 3 0.25 mm)
n.r., not reported. Solvents: Acet, acetone; AcN, acetonitrile; Hex, hexane; DCM, dichloromethane; EtOAc, ethyl acetate; i-PrOH, 2-propanol; DE, diethyl ether; MeOH, methanol; EtOH, ethanol; Cyclohex, cyclohexane; PE, petroleum ether. Solvent mixtures: proportions as v=v; TEA, triethylamine; Py, pyrethroids; ON, organonitrogen; HFM, hollow fiber membrane; SPME, solid-phase microextraction; PDMS-DVB, polydimethylsiloxane –divinylbenzene; LP, low pressure; SFE, supercritical fluid extraction; SBSE, stir bar sorptive extraction; SFC, supercritical fluid chromatography; NPLC, normal phase liquid chromatography; SIM, selected ion monitoring; IT, ion trap; EI, electron impact; ECNI, electron capture negative ionization; APCI, atmospheric pressure chemical ionization; ESI, electrospray; TSP, thermospray.
184 TABLE 7.2
Overview of Typical Analytical Procedures Used for the Determination of Pesticides by GC or LC with Classical Detectors in Foods of Animal Origin
Recovery Pesticide
Sample Type
(%) References OPs
Cow milk (25),
59 –117 [40] Analysis liver, and muscle
Acet:AcN 1:4 þ DCM
SPE C 18 ZB-5 (30 m 3 0.32 mm
GC-NPD
partition þ Na 2 SO 4 (AcN)
3 0.25 mm) þ ZB-50
boar (10)
(30 m 3 0.32 mm
Hydromatrix þ SFE (CO 2 )
Florisil (heptane
DB-1701 (30 m
3 0.32 mm 3 0.25 mm)
OPs Fat (0.75)
Warm (hydromatrix þ water)
Florisil
DB-1 (30 m
GC-FPD
a þ 3% AcN) MSPD (silica gel þ
þ SFE (CO 2 3 0.53 mm 3 1.5 mm)
OPs a Milk (5)
Pyrex glass column
GC-NPD
92 –96 [43] in
Na 2 SO 4 ); Acet:DCM 2:1
(1 m 3 2 mm i.d.)
Food
b Butter (5)
Melt (508C) and filter þ Hex
þ AcN partition þ DCM
and
partition þ Na 2 SO 4
OPs, Herbicides Milk, cheese
AcN þ Hex partition
Florisil
DB-1 (30 m 3 0.32 mm
OPs Milk (50)
Shake (EtOAc þ Na 2 SO 4 ),
HP-1 (25 m 3 0.20 mm
GC-FPD
dryness (Hex) þ AcN
3 0.25 mm)
saturated in Hex extraction
OPs Milk (10)
AcN þ EtOH in Ultra Turrax
SPB-608(15 m
GC-FPD
þ dispersion on solid matrix
3 0.53 mm 3 0.83 mm)
Samples
diatomaceous
Determination OPs
a Milk (10)
a Acet:AcN þ DCM
a SPE C 18 DB-17 (15 m
GC-FPD
n.r. [47]
3 0.53 mm 3 1.0 mm)
b Butterfat (1)
b Hex þ Extrelux þ C 18
columns þ MeOH
Py (acrinathrine Honey (1)
91 –101 [48] and
Shake (water) þ benzene:
Florisil cartridge
DB-17 (25 m 3 0.25 mm
GC-FID
of metabolites)
i -PrOH 1:1 Shake (MeOH)
(Hex:DCM 1:1)
3 0.25 mm)
Pesticides Py
Milk (10)
AcN:EtOH (5:1) þ solid
GPC
DB-17 (15 m 3 0.53 mm
GC-ECD
matrix diatomaceous
3 1.5 mm)
OCs Chicken eggs (1)
MSPD –Florisil (DCM)
DB-5 MS (30 m
GC-ECD
in Carbamates
3 0.25 mm 3 0.25 mm)
Egg (25)
Acetonitrile –polytron
Aminopropyl
Hypersil C 18 (250 mm
LC-fluorescence
OPs, Py Honey (1 –5)
Shake (water=MeOH) þ
Florisil column
Animal OPs, Py
SPME (PDMS)
(Hex:DCM 1:1)
3 0.25 mm 3 0.25 mm)
GC-NPD
Honey (1.5)
Shake (water þ phosphate
HP-5 (30 m 3 0.32 mm
GC-AED
buffer) þ SPME (PDMS)
3 0.25 mm)
OPs, Py Honey (20)
Hex:i-PrOH 6:3 þ water with
RP-18 (250 mm
OPs Honey (1)
Shake (water) þ SPME (sol–
HP-5 (30 m 3 0.32 mm
GC-FPD
gel crown ether fiber)
3 0.25 mm)
Misc. Honey (2)
78 –98 [57] insecticides
Shake (water) þ SPE C 18 —
Hypersil (250 mm
LC-UV
3 4.6 mm)
Benomyl, Honey (1)
91 –99 [58] carbendazim
Shake (HCl, 0.05 M þ
Novapack C 18 (150 mm
LC-fluorescence
EtOAc) þ EtOAc þ NaOH
3 3.9 mm)
0.1 M þ EtOAc
Atrazine and Honey (5)
84 [59] simazine
Ultrasonic extraction
HPTLC Silica gel
TLC
(benzene:water 1:1)
(10 3 20 cm)
(continued ) 185
TABLE 7.2 (continued) Overview of Typical Analytical Procedures Used for the Determination of Pesticides by GC or LC with Classical Detectors in Foods of Animal Origin
Recovery Analysis Pesticide
Sample Type
(%) References OCs
Fish and shellfish
Soxhlet, Hex
SPE-SPE
SPB-608 (30 m
GC-ECD
(C 18 þ Florisil
3 0.53 mm 3 0.5 mm)
of
Pesticides OCs, OPs, Py,
or alumina)
70 –140 [61] and carbamates
Fish and shellfish
Blending with water, Acet,
SPE –SPE
n.r.
GC-ECD; GC-
FPD; LC-UV
aminopropyl) þ AcN
in Benomyl,
74 –122 [62] Food thiabendazole
Table-ready food
Acetone —blender
SCX cartridge
Platinum C 8 (150 mm
LC-fluorescence
and n.r., not reported. Solvents: Acet, acetone; AcN, acetonitrile; Hex, hexane; DCM, dichloromethane; EtOAc, ethyl acetate; i-PrOH, 2-propanol; MeOH, methanol; EtOH, ethanol. Solvent mixtures: proportions as v=v; Py, pyrethroids; SPME, solid-phase microextraction; SPMD, solid-phase matrix dispersion; SFE, supercritical fluid extraction;
Environmental TLC, thin layer chromatography; GPC, gel permeation chromatography; ECD, electron capture detection; FID, flame ionization detection; FPD, photometric detection; NPD,
nitrogen –phosphorus detection; UV, ultraviolet detection; DAD, diode array detection.
Samples
Determination of Pesticides in Food of Animal Origin 187 particular physicochemical properties of various classes of pesticides, the determin-
ation of some pesticides may require specific analytical approaches.