PARAQUAT
C12 H14 N2Cl2 MW: 257.16 CAS: 4685-14-7 (ion) (C12 H14 N2)2+ (M.W. Paraquat = 186.26) METHOD: 5003, Issue 2
5003
RTECS: DW1960000 (ion)
EVALUATION: FULL
OSHA : 0.5 mg/m 3 (skin; respirable) NIOSH: 0.1 mg/m 3 (skin; respirable) ACGIH: 0.1 mg/m 3 (respirable; 0.5 mg/m 3 total)
Issue 1: 15 February 1984 Issue 2: 15 August 1994
PROPERTIES: (dichloride salt) solid; decomposes @ 300 °C; VP not significant
SYNONYMS: 1,1'-dimethyl-4,4'-bipyridinium dichloride; methyl viologen; CAS # 1910-42-5; 1,1'-dimethyl-4,4'-bipyridinium bis methyl sulfate (CAS #2074-50-2). SAMPLING SAMPLER:
FILTER (1-µm PTFE membrane)
FLOW RATE:
1 to 4 L/min
VOL-MIN: -MAX:
40 L @ 0.5 mg/m 3 1000 L
SHIPMENT:
routine
SAMPLE STABILITY:
at least 1 week @ 25 °C
BLANKS:
2 to 10 field blanks per set
ACCURACY RANGE STUDIED:
0.26 to 1.03 mg/m 3 [1] (90-L samples)
BIAS:
- 0.97%
ˆ ): 0.088 [1] OVERALL PRECISION (S rT ACCURACY:
MEASUREMENT TECHNIQUE:
HPLC, UV DETECTION
ANALYTE:
1,1-dimethyl-4,4'-bipyridium cation
DESORPTION:
5 mL water
INJECTION VOLUME:
20 µL
MOBILE PHASE:
25% acetonitrile; 75% 0.01 M heptanesulfonic acid, sodium salt (pH 3.2); 1.5 mL/min
COLUMN:
30 cm x 4-mm ID stainless steel packed with µ-Bondapak C 18 or equivalent
DETECTOR:
UV absorption @ 254 nm
CALIBRATION:
Paraquat dichloride in water
RANGE:
20 to 500 µg/sample [2,3]
ESTIMATED LOD: 10 µg/sample [2] PRECISION (Sr):
0.048 [1]
± 17.1%
APPLICABILITY: The working range is 0.1 to 10 mg/m 3 for a 200-L air sample. The paraquat cation is the analyte for this method; therefore, either salt, the dichloride or bismethyl sulfate, can be quantitated. The standards are prepared from a solution of the dichloride salt with appropriate stoichiometric factor applied.
INTERFERENCES: None identified.
OTHER METHODS: This revises Method S294 [2].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
