Suggestions
Use up and down arrows to review and enter to select.Please wait while we process your payment
If you don't see it, please check your spam folder. Sometimes it can end up there.
If you don't see it, please check your spam folder. Sometimes it can end up there.
Please wait while we process your payment
By signing up you agree to our terms and privacy policy.
Don’t have an account? Subscribe now
Create Your Account
Sign up for your FREE 7-day trial
Already have an account? Log in
Your Email
Choose Your Plan
Individual
Group Discount
Save over 50% with a SparkNotes PLUS Annual Plan!
Purchasing SparkNotes PLUS for a group?
Get Annual Plans at a discount when you buy 2 or more!
Price
$24.99 $18.74 /subscription + tax
Subtotal $37.48 + tax
Save 25% on 2-49 accounts
Save 30% on 50-99 accounts
Your Plan
Payment Details
Payment Summary
SparkNotes Plus
You'll be billed after your free trial ends.
7-Day Free Trial
Not Applicable
Renews April 5, 2024 March 29, 2024
Discounts (applied to next billing)
DUE NOW
US $0.00
SNPLUSROCKS20 | 20% Discount
This is not a valid promo code.
Discount Code (one code per order)
SparkNotes PLUS Annual Plan - Group Discount
Qty: 00
SparkNotes Plus subscription is $4.99/month or $24.99/year as selected above. The free trial period is the first 7 days of your subscription. TO CANCEL YOUR SUBSCRIPTION AND AVOID BEING CHARGED, YOU MUST CANCEL BEFORE THE END OF THE FREE TRIAL PERIOD. You may cancel your subscription on your Subscription and Billing page or contact Customer Support at custserv@bn.com. Your subscription will continue automatically once the free trial period is over. Free trial is available to new customers only.
Choose Your Plan
For the next 7 days, you'll have access to awesome PLUS stuff like AP English test prep, No Fear Shakespeare translations and audio, a note-taking tool, personalized dashboard, & much more!
You’ve successfully purchased a group discount. Your group members can use the joining link below to redeem their group membership. You'll also receive an email with the link.
Members will be prompted to log in or create an account to redeem their group membership.
Thanks for creating a SparkNotes account! Continue to start your free trial.
Please wait while we process your payment
Your PLUS subscription has expired
Please wait while we process your payment
Please wait while we process your payment
Serum and plasma selenium responds to short-term changes in diet and measuring the amounts of selenium in serum and plasma can indicate short-term selenium status. Normal selenium levels of the U.S. population fall within the range of 2.03-3.29 micromoles (mcmol) per liter (L).
Selenium levels in whole blood do not fluctuate much and are thus more indicative of long-term selenium status. A new technique that can be used to analyze serum, plasma or whole blood selenium is called graphite furnace atomic absorption spectrometry. This method is fairly easy to execute and the resultant samples require little pretreatment.
Urine samples reflect selenium content of the previous meal and are not useful for assessment of selenium status, though they can be used to detect toxicity.
Toenail selenium is useful for assessment of long-term selenium status. Selenium is incorporated into toenails as they grow. Because the exposed toenail on which tests are done have long since ceased to grow, toenail selenium levels probably reflect zinc status as it stood six to nine months prior to testing.
There is a correlation between blood glutathione peroxidase activity and blood selenium up to 1.2 mcmol/L. Beyond that point the activity plateaus, and cannot be used to determine selenium status. The test is not specific because other factors can affect glutathione peroxidase activity. Such factors include age, sex, ethnicity, iron-deficiency anemia, essential fatty acid deficiency, and vitamin B12 deficiency.
Please wait while we process your payment