Strychnine (5016)
STRYCHNINE
C21 H22 N2O2
MW: 334.42
METHOD: 5016, Issue 2
CAS: 57-24-9
5016
RTECS: WL2275000
EVALUATION: FULL
OSHA : 0.15 mg/m 3 NIOSH: 0.15 mg/m 3/10 h; Group I Pesticide ACGIH: 0.15 mg/m 3
PROPERTIES:
Issue 1: 15 May 1985 Issue 2: 15 August 1994
solid; MP 268 °C; VP not significant
SYNONYMS: strychnidin-10-one
SAMPLING SAMPLER:
FILTER (glass fiber, 37-mm)
FLOW RATE:
1 to 3 L/min
VOL-MIN: -MAX:
70 L @ 0.15 mg/m 3 1000 L
SHIPMENT:
routine
SAMPLE STABILITY:
at least 7 days @ 25 °C [1]
BLANKS:
2 to 10 field blanks per set
ACCURACY RANGE STUDIED:
0.073 to 0.34 mg/m 3 [3] (180-L samples)
BIAS:
4.4%
ˆ ): 0.059 [1] OVERALL PRECISION (S rT ACCURACY:
MEASUREMENT TECHNIQUE:
HPLC, UV DETECTION
ANALYTE:
strychnine
DESORPTION:
5 mL mobile phase
INJECTION VOLUME:
20 µL
COLUMN:
25 cm x 4.2-mm ID, packed with µBondpack C18, 10-µm particle size
MOBILE PHASE:
aqueous 1-heptane sulfonic acid + CH 3CN; pH 3.5; 1 mL/min @ ambient temperature
DETECTOR:
UV absorption @ 254 nm
CALIBRATION:
solutions of strychnine in mobile phase
RANGE:
10 to 70 µg per sample
ESTIMATED LOD: 0.8 µg per sample [1,2] PRECISION (Sr):
0.042 @ 13 to 62 µg per sample [1]
± 14.6%
APPLICABILITY: The working range is 0.05 to 10 mg/m 3 for a 200-L air sample.
INTERFERENCES: None known.
OTHER METHODS: This revises Method S302 [2].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 STRYCHNINE: METHOD 5016, Issue 2, dated 15 August 1994 - Page 2 of 3 EQUIPMENT:
REAGENTS: 1. 2. 3. 4. 5. 6. 7. 8.
9.
Strychnine, 98%.* Acetonitrile, chromatographic quality. Water, chromatographic quality. Acetonitrile:water, 1:1 (v/v). Mix equal volumes of acetonitrile and distilled water. Acetic acid, glacial.* Acetic acid, 0.01 N. Dilute 0.6 mL glacial acetic acid to 1 L with distilled water. 1-Heptanesulfonic acid sodium salt, 95%. Calibration stock solution, 1 mg/mL strychnine in 0.01 N acetic acid. Use an ultrasonic bath to aid dissolution. Mobile phase: Dissolve 1.1014 g 1heptanesulfonic acid sodium salt in 980 mL. 1:1 acetonitrile:water. Adjust pH to 3.5 with glacial acetic acid. Dilute to 1 L with 1:1 acetonitrile:water. Filter through 0.45-µm PTFE filter and refrigerate. Prepare fresh weekly and if cloudiness appears.
1. Sampler: glass fiber filter, 37-mm diameter, in cassette filter holder. 2. Personal sampling pump, 1 to 3 L/min, with flexible connecting tubing. 3. HPLC, UV absorption detector at 254 nm, recorder, integrator and column (page 5016-1). 4. Syringe filter, polypropylene housing, nylon membrane, 0.2-µm pore size. 5. Syringe, 20-µL. 6. Micropipets or syringes, 10- to 100-µL. 7. Jars, glass, squat-form ointment, with PTFE-lined screw caps. 8. Volumetric flasks, glass, 10-mL. 9. Pipet, 5-mL delivery, with pipet bulb. 10. Tweezers. 11. Ultrasonic bath.
See SPECIAL PRECAUTIONS.
SPECIAL PRECAUTIONS: Strychnine is a potent convulsant. Use impervious clothing, gloves and face shields when handling it [3,4]. Avoid skin contact with acetic acid as it may cause severe burns.
SAMPLING: 1. 2.
Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 3 L/min for a total sample size of 70 to 1000 L.
SAMPLE PREPARATION: 3. 4. 5.
Transfer the filter carefully using tweezers to an ointment jar. Add 5.0 mL mobile phase. Seal and gently swirl the jar to wet the filter. Filter the sample solution through a syringe filter.
CALIBRATION AND QUALITY CONTROL: 6.
7.
Calibrate daily with at least six working standards over the range 1 to 70 µg strychnine per sample (0.2 to 14 µg/mL). a. Add known amounts of calibration stock solution to mobile phase in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with the samples and blanks (steps 9, 10, and 11). c. Prepare calibration graph (peak area vs. µg strychnine). Determine recovery (R) at least once for each lot of filters used for sampling in the calibration range. Prepare three filters at each of five levels plus three media blanks. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 STRYCHNINE: METHOD 5016, Issue 2, dated 15 August 1994 - Page 3 of 3 a. b. c.
8.
Deposit a known amount of calibration stock solution onto the filter. Allow filters to air dry. Store samples overnight in ointment jars. Prepare for analysis (steps 3 through 5) and analyze together with working standards (steps 9 through 11). d. Prepare a graph of R vs. µg strychnine recovered. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and R graph are in control
MEASUREMENT: 9. 10. 11.
Set HPLC system according to manufacturer's recommendations and to the conditions given on page 5016-1. Inject sample aliquot using syringe, fixed volume sample loop or autosampler. Measure peak area.
CALCULATIONS: 12. 13.
Determine the mass, µg (corrected for R) of strychnine found in the sample (W) and in the average media blank (B) from the calibration graph. Calculate concentration, C, of strychnine in the air volume sampled, V (L):
EVALUATION OF METHOD: Method S302 was issued on February 17, 1978 [2], and evaluated over the range 0.073 to 0.34 mg/m using a 180-L sample [1,5]. Overall precision, SˆrT, was 0.059 with an average recovery of 100.9%, representing a non-significant bias. The concentration of strychnine was independently verified by analysis of filter samples with a UV spectrophotometer at 254 nm. Recovery was 0.98 in the range of 13.5 to 54.1 µg per sample. Collection efficiency was determined to be at least 98.8% for 180-L sample at a concentration to be 0.15 µg/mL. Average recovery for one-day old samples was 105% vs. 98.8% for seven-day old samples stored at room temperature. Since the filter samples for the recovery and stability studies were prepared with strychnine acetate rather than the free base, the recovery of the free base and the stability of such samples is unknown. REFERENCES: [1] [2] [3]
[4]
[5]
Back-up Data Report for Strychnine, NIOSH Contract No. 210-76-0123, available as "Ten NIOSH analytical Methods," Order Nol PB288-629 from NTIS, Springfield, VA 22161. NIOSH Manual of Analytical Methods, 2nd ed., Vol. 5, S302, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 79-141 (1979). Criteria for a Recommended Standard...Occupational Exposure During the Manufacture and Formulation of Pesticides, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 78-174 (1978), available as PB81-227001 from NTIS, Springfield, VA 22161. NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, U.S. Department of health and Human Services, Publ. (NIOSH) 81-123 (1981), available as GPO Stock #017-033-00337-8 from Superintendent of Documents, Washington, D.C. 20402. NIOSH Research Report - Development and Validation of Methods for Sampling and analysis of Workplace and Toxic Substances, U.S. Department of Health and Human Services, Publ. (NIOSH) 80-133 (1980).
METHOD REVISED BY: M.J. Seymour, NIOSH/DPSE. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
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