Page:NIOSH Manual of Analytical Methods - 8326.pdf/9

 S-Benzylmercapturic acid and S-phenylmercapturic acid in urine: METHOD 8326, Issue 1, dated 20 May 2014 - Page 9 of 10

Table 2. MULTIPLE LEVEL RECOVERY EXPERIMENT of BMA and PMA FROM URINE

Analyte BMA2

Analyte added (ng/mL) 1

Mean background Mean corrected concentration concentration (ng/mL, n = 9) (ng/mL, n = 9) 7.43 7.18

Standard Average deviation recovery (%) (ng/mL) 103 0.37

%RSD1 5.0

BMA2

2

8.44

8.18

103

0.19

2.3

BMA

8

14.6

14.2

103

0.32

2.2

BMA

30

38.2

36.2

106

0.94

2.4

PMA

1

1.02

1.00

102

0.05

4.9

PMA

2

2.10

2.00

105

0.09

4.3

PMA

8

8.23

8.00

103

0.27

3.3

PMA

30

31.9

30.0

106

0.65

2.0

2 2

Notes:	1. %RSD = percent relative standard deviation 2. The non-fortified reference urine had a background level of 6.2 ng/mL BMA and no detectable level of PMA. Three different spiked samples were prepared at each level and analyzed during three separate experimental trial runs (a total of nine samples at each spike level were analyzed). The same C18 column was used for experimental batch trials 1 and 2; a second C18 column was used on trial run 3.

Table 3. MULTIPLE LEVEL RECOVERY EXPERIMENT of BMA and PMA FROM A URINE SUBSTITUTE Analyte Mean Average Standard added concentration recovery deviation Analyte (ng/mL) (ng/mL, n = 9) (%) (ng/mL) %RSD1 BMA 1 1.07 107 0.31 29 BMA 2 2.13 106 0.34 16 BMA 8 8.31 104 0.53 6.4 BMA

30

30.7

102

0.76

2.5

PMA PMA PMA PMA

1 2 8 30

1.09 1.98 7.96 31.1

109 99 100 104

0.27 0.16 0.48 0.91

25 7.9 6.0 2.9

Notes:	1. %RSD = percent relative standard deviation. Three different spiked samples were prepared at each level and analyzed during three separate experimental trial runs (a total of nine samples at each spike level were analyzed).

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition