The time to wait before collecting plant samples after potassium dichromate (Cr(VI)) exposure for Atomic Absorption Spectroscopy (AAS) depends on the study objective.

* For **metal accumulation studies**, samples are typically collected **after 7–10 days** of exposure. For example, *Plantago ovata* seedlings were exposed for 10 days, then harvested and analyzed using AAS: [https://link.springer.com/article/10.1186/s41021-018-0109-0](https://link.springer.com/article/10.1186/s41021-018-0109-0)

* For **short-term response studies**, samples can be collected as early as **1, 6, or 24 hours** post-exposure. For example, *Zea mays* seedlings were sampled at these intervals to study uptake kinetics: [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709723/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709723/)

In summary:

* **1–24 hours** for early response or uptake studies

* **7–10 days** for accumulation and chronic toxicity studies

So @Ms. Amber, you may choose based on your study goals

Also these studies illustrate that sampling times can range from a few hours to several days post-exposure, depending on the research focus.

Short-term exposures

(hours) are often used to study immediate physiological and biochemical responses, while longer exposures (days) are suitable for assessing accumulation and chronic effects.

For your specific research objectives, it would be advisable to conduct a preliminary time-course study to determine the most appropriate sampling intervals that align with your goals, whether they pertain to acute toxicity responses or long-term accumulation patterns.