Page:NIOSH Manual of Analytical Methods - 9106.pdf/22

 METHAMPHETAMINE. . .on Wipes by Liquid-Liquid Extraction: METHOD 9106, Issue 1, dated 17 October 2011 - Page 22 of 31

Table 11a. Recovery from latex-painted wall with various solvents; one gauze wipe compared with the sum of two gauze wipes(1,2) Water(3) First Gauze Wipe

Test Compound(5)

Percent

%RSD

Amphetamine

51

14

Cocaine

36

Ephedrine MDMA

Isopropanol Plus Second Wipe(4) Percent

Methanol

Plus Second Wipe(4)

First Gauze Wipe

Percent

First Gauze Wipe

Percent

%RSD

Plus Second Wipe(4)

Percent

%RSD

Percent

56

67

6.0

78

90

4.0

96

22

36

69

22

80

89

9.1

94

48

23

52

76

7.4

85

91

4.4

96

40

20

44

61

9.0

70

88

5.3

94

MDEA

45

22

50

69

12

80

90

11

97

Methamphetamine

46

16

50

64

7.4

75

87

3.5

94

Phencyclidine

27

26

30

64

9.6

73

86

5.2

91

Phentermine

53

9.2

58

78

6.6

91

95

2.9

101

Phenylpropanolamine

58

21

62

80

9.3

95

85

5.0

94

Pseudoephedrine

49

20

53

73

7.0

85

95

3.3

101

(1)	 Backup Data Report for NIOSH 9109 [8]. Area of each sample was 100 cm. (2)	 Wall was an existing standard gypsum board wall painted with a latex based paint. Painted surface was at least one year old. There were six replicates for each solvent tested. (3)	 Water was deionized water (ASTM type II). Note low recovery and high %RSD. (4)	 For the serial wipe study, each 100-cm2 area was wiped again with a fresh pre-wetted gauze wipe and the amount recovered was determined separately. In practice, a second (serial) wipe is included with the first gauze wipe; both gauze wipes constitute a single sample. The percent recoveries shown in the column represent the sum of the amounts recovered in both the first and second wipes. (5)	 Each pre-measured area was spiked with 3 µg of each analyte in methanol and the methanol allowed to dry for several minutes prior to wipe sampling. 2

Table 11b. Recovery from various surfaces with various solvents; one gauze wipe compared with the sum of two gauze wipes(1) Isopropanol First Gauze Wipe

Surface Material(3) Enamel (lid of washing machine) Vinyl veneer on particle board Latex painted wall Refrigerator door Varnished hardwood panel Formica® countertop

Replicates 4(3) 4(4) 6(3) 2(4) 2(5) 4(4)

Percent 58 60 64 65 72 75

%RSD 5.7 5.2 7.4 2.9 5.4 4.9

Methanol

Plus Second Wipe Percent 68 68 75 76 76 82

(2)

First Gauze Wipe

Percent 81 81 87 91 82 87

%RSD 2.4 4.8 3.5 4.0 3.7 3.8

Plus Second Wipe(2) Percent 87 89 94 92 86 91

(1)	 Backup Data Report for NIOSH 9109 [8]. Area of each sample was 100 cm2. (2)	 For the serial wipe study, each 100-cm2 area was wiped again with a fresh pre-wetted gauze wipe and the amount recovered was determined separately. In practice, a second (serial) wipe is included with the first gauze wipe; both gauze wipes constitute a single sample. The percent recoveries shown in the column represent the sum of the amounts recovered in both the first and second wipes. (3)	 The Refrigerator door and the washing machine lid were from used appliances. The vinyl-veneered particle board (a book shelf), the Formica® countertop, and the varnished hardwood paneling were all purchased new. All surfaces of used and new materials were pre-cleaned with multiple rinses of methanol prior to spiking. Each pre-measured 100-cm2 square was spiked with 3 µg methamphetamine. (4)	 Samples were taken using the side-to-side and then top-to-bottom wiping technique. (5)	 Half of the samples were wiped using the side-to-side wiping technique and half were wiped using the concentric squares wiping technique. There were no significant differences in recoveries. Percent recoveries and %RSDs are for both techniques combined. (6)	 Samples were taken each time using only top-to-bottom wiping with the grain of the wood in an “N” pattern. Method rev. 1.1.1

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition