Page:NIOSH Manual of Analytical Methods - 5603.pdf/1

 ALACHLOR in Air C14H20O2NCl

MW: 269.6

METHOD: 5603, Issue 1

OSHA : NIOSH: ACGIH:

5603

CAS: 15972-60-8

EVALUATION: FULL

no PEL no REL no TLV

PROPERTIES:

RTECS: AE1225000 Issue 1: 15 January 1998

colorless crystalline solid; d 1.133 g/mL @ 25 C; MP 39.5 to 41.5 C; VP 0.0029 Pa (2.2 x 10-5 mm Hg) @ 25 C; solubility in water 242 mg/L @ 25 C.

SYNONYMS: 2-Chloro-2',6'-diethyl-N-(methoxymethyl)acetanilide; Lasso; Alanex; Alanox; Chimiclor

SAMPLING SAMPLER:

SOLID PHASE EXTRACTION (SPE) DISK (Styrene divinyl benzene [SDB]-xc disk)

MEASUREMENT TECHNIQUE:

ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA)

ANALYTE:

Alachlor

FLOW RATE: 1 L/min VOL-MIN: -MAX:

70 L 1750 L

EXTRACTION:

2 mL methanol

SHIPMENT:

routine

WAVELENGTH:

450 nm

at least 7 days at 25 C at least 21 days at 4 C

CALIBRATION:

standard solutions of alachlor in methanol in water

RANGE:

20 to 500 ng per sample [1]

ESTIMATED LOD:

9 ng per sample [1]

PRECISION ( r):

0.072 [1]

SAMPLE STABILITY:

BLANKS:

1%

2 to 10 field blanks per set

ACCURACY RANGE STUDIED:

0.24 to 120 µg per sample

BIAS:

0.0368

OVERALL PRECISION ( ACCURACY:

rT

):

0.078 (12 µg to 48 µg) [1] ± 17.4%

APPLICABILITY: This method provides a quantitative evaluation of alachlor in air utilizing ELISA technology designed to determine the concentration of alachlor in water. The limit of quantitation for the overall method is 20 ng/sample because of the need to negate the interferences of methanol in the ELISA. The assay is simple and adaptable enough that it may be used on site in the field as a screening method.

INTERFERENCES: 2-[(2,6-diethyl-phenyl)(methoxymethyl)amino]-2-oxoethane sulfonic acid (ESA) cross reacts with alachlor in the ELISA. ESA is not detected by standard HPLC or GC [2]. Alachlor related acetanilides may interfere with the determination of alachlor, such as acetochlor, metolachlor, and metalaxyl. The ELISA is also sensitive to the concentration of organic solvent remaining in the assay from solid phase extraction.

OTHER METHODS: Other ELISA kits may be used in a similar manner. Alachlor also is included in Method 5602, Chlorinated and Organonitrogen Herbicides in Air by GC/ECD [3].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition