Total C and the 13C/12C ratios of the roots were determined by isotope ratio mass spectrometry (IRMS) using an elemental analyzer (EA 1110; Carlo Erba, Italy) coupled with a mass spectrometer (Delta S; Thermo Finnigan, Germany). The δ13C value was expressed relative to the international V-PDB standard and the analytical precision, which is the standard deviation (SD) of the measured results of the working standard (plant biomass), was 0.2‰.
Delta s
Manufactured by Thermo Fisher Scientific
Sourced in Germany
The Delta S is a high-precision scale designed for laboratory use. It provides accurate measurements of weight with a range of up to 1200 grams and a readability of 0.001 grams. The Delta S is suitable for a variety of applications that require precise weighing, such as sample preparation, chemical analysis, and quality control.
Automatically generated - may contain errors
5 protocols using delta s
1
Isotopic Analysis of Plant Roots
2
Carbon Isotope Analysis of Plant Needles
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
At the final harvest, several needles from apical shoots were sampled, dried for 48 h at 70 °C and ground into a fine powder using a ball mill (Retsch GmbH, Haan, Germany). Subsamples of 1 mg ± 0.1 mg were weighed into tin capsules and the carbon isotopic composition was measured with an isotope ratio mass spectrometer (Thermo-Finnigan, Delta S, Bremen, Germany). The carbon isotope composition (δ13C) was calculated according to the international standard (Vienna Pee Dee Belemnite, VPDB) using the following equation: δ13C = (Rs – Rstd)/Rstd × 1000, where Rs and Rstd are the isotopic ratios 13C/12C of the sample and the standard, respectively. The precision of spectrometric analysis (standard deviation of δ13C) was assessed with a calibrated, internal laboratory reference material with a matrix close to the measured samples (n = 16, SD = 0.05‰).
3
Quantifying Soil Carbon and Nitrogen Dynamics
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
Soil organic C (SOC) and total soil N concentrations, δ 13 C and At% 15 N in density fractions, were measured using an elemental analyzer (Carlo Erba NA 1500, CE Instruments, Rodano, Italy) coupled with an isotopic ratio mass spectrometer (Thermo-Finnigan, Delta S, Bremen, Germany). The δ 13 C (in % ) was calculated as follows:
where 13 R = 13 C/ 12 C and the standard is the international Vienna Pee Dee Belemnite. The At% 15 N (in %) was calculated according to the following: 15 N atoms/(no. of ( 15 N + 14 N) atoms)] × 100.
(
The fraction of total SOC coming from residue C (f C , in g residue C g -1 total SOC) and total soil N coming from residue N (f N , in g residue N g -1 total soil N) was calculated as follows:
where δ TR and At TR represent δ 13 C and At% 15 N of the soil receiving residue, δ C and At C represent δ 13 C and At% 15 N of the control soil (no residue), and δ R and At R represent δ 13 C and At% 15 N of the corn residue, respectively. Residue C and N concentrations in soil (in g residue C or N kg -1 soil) were as follows:
where SOC and SN are the concentrations of total soil organic C (g SOC kg -1 soil) and total soil N (g total soil N kg -1 soil), respectively.
where 13 R = 13 C/ 12 C and the standard is the international Vienna Pee Dee Belemnite. The At% 15 N (in %) was calculated according to the following: 15 N atoms/(no. of ( 15 N + 14 N) atoms)] × 100.
(
The fraction of total SOC coming from residue C (f C , in g residue C g -1 total SOC) and total soil N coming from residue N (f N , in g residue N g -1 total soil N) was calculated as follows:
where δ TR and At TR represent δ 13 C and At% 15 N of the soil receiving residue, δ C and At C represent δ 13 C and At% 15 N of the control soil (no residue), and δ R and At R represent δ 13 C and At% 15 N of the corn residue, respectively. Residue C and N concentrations in soil (in g residue C or N kg -1 soil) were as follows:
where SOC and SN are the concentrations of total soil organic C (g SOC kg -1 soil) and total soil N (g total soil N kg -1 soil), respectively.
4
Sulfur Isotope Analysis of H2S
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
For analysis of δ34S of the H2S (converted to Ag2S) was conducted at the Institute of Geology and Geophysics, Chinese Academy of Sciences. The dried Ag2S and Cu2O were generally mixed in a proportion of 1:10 and then combusted at 1100 °C under vacuum to produce SO2. The resulting SO2 was sealed within pyrex tubing and analyzed on a Thermo Delta S mass spectrometer. Sulfur isotope values are expressed as per mil (‰) deviations from the sulfur isotope composition of the Vienna Canyon Diablo Troilite (VCDT) using the conventional delta (δ34S) notation. Isotopic results were generally reproducible within ± 0.3‰.
5
Measuring N2 Fixation in Cyanobacteria
Check if the same lab product or an alternative is used in the 5 most similar protocols
+ Expand
The PON and POC content were measured for Nodularia cultures and Nostoc punctiforme sp. 73.1 grown in N-free medium on day 14. Due to budget constraints, the remaining Nostoc cultures were not studied. Filters containing culture samples were trimmed, sectioned, then loaded into tin capsules and palletised for isotopic analysis. Measurement was done by means of flash combustion in a Carlo Erba EA 1108 at 1020 °C in a Thermo Finnigan Delta S mass-spectrometer. Calibration material for N and C analysis was acetanilide (Merck). N 2 fixation activity was determined by incubating cultures in two replicates per treatment with bubble addition of 15 N-N 2 enriched gas (99% 15 N 2 ) for 24 h, guaranteeing sufficient dissolution of the 15 N gas in the incubation bottle (Wannicke et al. 2018a ). Tracer incubations were terminated by gentle vacuum filtration (< 200 mbar) of the culture material through pre-combusted GF/F filters (Whatman) that were then dried at 60 °C, analysed and the N 2 fixation rates calculated (Montoya et al. 1996) . Two technical replicates were conducted per bottle.
About PubCompare
Our mission is to provide scientists with the largest repository of trustworthy protocols and intelligent analytical tools, thereby offering them extensive information to design robust protocols aimed at minimizing the risk of failures.
We believe that the most crucial aspect is to grant scientists access to a wide range of reliable sources and new useful tools that surpass human capabilities.
However, we trust in allowing scientists to determine how to construct their own protocols based on this information, as they are the experts in their field.
Ready to get started?
Sign up for free.
Registration takes 20 seconds.
Available from any computer
No download required
Revolutionizing how scientists
search and build protocols!