Elara’s heart thumped. Chemical interference, she scribbled. Formation of refractory oxides. She grabbed a new vial. This time, she added a releasing agent—lanthanum chloride—to break apart any lead-oxide compounds that might be hiding the true metal content.
The worksheet wasn’t just a training tool anymore. It was a roadmap. It had taught her to question the blank, to seek the signal beneath the noise, and to never trust a clear solution without checking for interference.
Not safe. Deadly.
Dr. Elara Vance stared at the worksheet on her lab bench. It wasn't just any worksheet; it was the worksheet—the one she’d designed a decade ago as a teaching assistant, now smudged with coffee rings and the graphite ghosts of erased answers.
Outside, the Meridian River glowed silver under the moon. Tomorrow, the truth would finally absorb the light. atomic absorption spectroscopy worksheet
She glanced at the second section: Digest the sample using a 1:1 nitric acid solution. Filter. Dilute to volume. She had done this. She had taken water from the riverbank, just below the old battery plant. But when she ran the sample through the AAS—that beautiful, humming machine that shattered light into element-specific wavelengths—the result matched the EPA’s lie: 0.48 ppm. Safe.
Too safe.
Section 3 was where things got interesting: List three spectral interferences and two chemical interferences that could cause false low results.
Elara didn't write an answer. She printed the new data, stapled the old worksheet to it, and walked to the district attorney’s office. Elara’s heart thumped