| C12H14N4O4S2 | MW: 342.40 | CAS: 23564-05-8 | RTECS: BA3675000 |
OSHA: N/A
NIOSH: N/A
ACGIH: N/A
| PROPERTIES: | colorless prisms; MP 181.5–182.5 °C; soluble in acetone, methanol, chloroform, acetonitrile, slightly soluble in other organics, insoluble in water |
SYNONYMS: Topsin-M; [1,2-phenylenebis(iminocarbonothioyl)]bisdimethyl ester carbamic acid
SAMPLING
| SAMPLER: | FILTER/SOLID SORBENT TUBE (OVS-2 tube: 11 mm quartz fiber filter; XAD-2, 270 ing/140 ing) |
| FLOW RATE: | 0.1 L/min to 1 L/min |
| VOL-MIN: | 20 L @ 0.1 L/min [see Evaluation of Method, Note 1.] |
| -MAX: | 480 L |
| SHIPMENT: | 4 °C |
| SAMPLE STABILITY: | at least 28 days at 4 °C |
| BLANKS: | 2 to 10 field blanks per set |
ACCURACY
| RANGE STUDIED: | not determined |
| BIAS: | not determined |
| OVERALL PRECISION (Ŝrτ): | not determined |
| ACCURACY: | not determined |
MEASUREMENT
| TECHNIQUE: | HPLC, UV detector |
| ANALYTE: | thiophanate-methyl |
| EXTRACTION: | 2 mL 40% isopropanol: 60% acetonitrile |
| INJECTION VOLUME: | 5 µL |
| MOBILE PHASE: | A = 2% n-propanol in water, 0.02 M TEA-PO4, pH adjusted to 7.0 ± 0.1 using phosphoric acid; B = 2% n-propanol in acetonitrile; gradient from 20% B to 70% B (20 min), decreasing to 20% B (2 min), hold at 20% B (5 min) |
| COLUMN: | reversed phase C-18, 4 µm, 250 × 2.00 mm (or equivalent) |
| DETECTOR: | UV @ 200 nm [see Evaluation of Method, Note 2.] |
| CALIBRATION: | solutions prepared in extraction solvent |
| RANGE: | 5 to 650 µg/sample |
| ESTIMATED LOD: | 0.76 µg/sample |
| PRECISION (Sr): | 0.0318 |
APPLICABILITY: This method was developed for the determination of thiophanate-methyl in air samples for a fungicide field study of orchard workers, and was meant to be used in conjunction with NMAM 5601 for the determination of carbendazim and captan as well. Recoveries of thiophanate-methyl may be lower when carbendazim, thiophanate-methyl, and captan are present in the same sample due to chemical interactions. The working range for this method is 0.025–5.67 ing/m³ based on a 100-L sample.
INTERFERENCES: Potential interferences to the analysis of thiophanate-methyl include other organic compounds, in particular other pesticides or fungicides that have the same retention time on a C-18 column. Positive identification may be confirmed by dual column chromatography using an appropriate alternative LC column. NOTE: It is possible to see a peak at the retention time for carbendazim, 9.8 minutes, since carbendazim is a decomposition product of thiophanate-methyl.
OTHER METHODS: This method is based in part on NMAM 5601 [1] for the development work. As such, several of the compounds listed in NMAM 5601can also be analyzed in conjunction with thiophanate-methyl using this method.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
