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 CHLORINATED AND ORGANONITROGEN HERBICIDES (AIR SAMPLING): METHOD 5602, Issue 1, dated 15 January 1998 - Page 10 of 14

TABLE 5. NOTES ON ANALYTICAL CHARACTERISTICS OF CHLORINATED ORGANONITROGEN AND ACID HERBICIDES Compound (alphabetically)

A.

B.

A. CHEMICAL

B. SAMPLE

C. GAS

AND PHYSICAL

PREPARATION

CHROMATOGRAPHIC

1

Alachlor

3

1

2

Atrazine

3

2,3

3

Cyanazine

1,3,4

2,4

4

2,4-D, acid

5

2.4-D, BE

1

1,2,4

6

2,4-D, EH

1

2

7

Metoloachlor

3

1

8

Simazine

3

2,3

2

2(methyl ester) 5

CHEMICAL AND PHYSICAL 1.

Esters may hydrolyze to the free acid. Free acid may also be present in formulations.

2.

Cyanazine contains a cyano group that appears to adversely affect analytical behavior.

SAMPLE PREPARATION 1.

Lower recoveries from glass fiber filters compared to quartz fiber filters.

2.

The esters are not affected by the diazomethane reagent provided the solutions are quenched within one hour with silicic acid. Recoveries for all esters diminish otherwise. This makes possible the speciation of 2,4-D esters and of the free acid in one analysis.

3.

Analytes were not affected by the diazomethane reagent.

4.

Generally high recoveries (120 to 150% or more) from XAD-2 resin compared to liquid standards for reasons unknown. Recoveries appear to be more realistic (80 to 90%) if the filter and the XAD-2 are desorbed and analyzed separately and the analytical results combined.

C.

GAS CHROMATOGRAPHIC 1.

Very good peak shape.

2.

Analyte has tendency to tailing on most column phases. Columns and injection ports must be clean and in good condition.

3.

The s-triazines, simazine, atrazine, and propazine, elute very close in that order on the

4.

Cyanazine is very polar and tends to tail and to elute very late on very polar columns. It

non-polar columns DB1and DB-5. The order is reversed on most polar columns. has very unpredictable behavior and peak areas either diminish or increase noticeably in subsequent injections. This behavior appears to be associated with the cyano group. 5.

2,4-D BE behaves similarly to cyanazine, chromatographically (see C.4.), though to a much lesser extent.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition