She flipped the worksheet over. On the back was the final section she’d added for her most advanced students: The last question read: If your result contradicts the official record, do you trust your instrument or the authority? Justify your answer based on the principles of atomic absorption.
Outside, the Meridian River glowed silver under the moon. Tomorrow, the truth would finally absorb the light.
She aspirated the new solution. The hollow cathode lamp for lead flickered to life, shooting a precise violet beam through the flame. The detector chattered. The software plotted a new point. atomic absorption spectroscopy worksheet
Section 3 was where things got interesting: List three spectral interferences and two chemical interferences that could cause false low results.
But tonight, the curve wasn't for a classroom. It was for the cold case of the Meridian River. For six months, the EPA had claimed the lead levels were safe. Elara suspected a lie. The townspeople were sick. The fish were dying. But the official reports showed a clean, linear slope—a perfect correlation. She flipped the worksheet over
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.
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. Outside, the Meridian River glowed silver under the moon
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 Trace Evidence