Fighting carbon loss of degraded peatlands by jump-starting ecosystem functioning with ecological restoration.

Degradation of ecosystems is a great concern on the maintenance of biodiversity and ecosystem services. Ecological restoration fights degradation aiming at the recovery of ecosystem functions such as carbon (C) sequestration and ecosystem structures like plant communities responsible for the C sequestration function. We selected 38 pristine, drained and restored boreal peatland sites in Finland and asked i) what is the long-term effect of drainage on the peatland surface layer C storage, ii) can restoration recover ecosystem functioning (surface layer growth) and structure (plant community composition) and iii) is the recovery of the original structure needed for the recovery of ecosystem functions? We found that drainage had resulted in a substantial net loss of C from surface layer of drained sites. Restoration was successful in regaining natural growth rate in the peatland surface layer already within 5 years after restoration. However, the regenerated surface layer sequestered C at a mean rate of 116.3 g m(-2) yr(-1) (SE 12.7), when a comparable short-term rate was 178.2 g m(-2) yr(-1) (SE 13.3) at the pristine sites. The plant community compositions of the restored sites were considerably dissimilar to those of pristine sites still 10 years after restoration. We conclude that ecological restoration can be used to jump-start some key peatland ecosystem functions even without the recovery of original ecosystem structure (plant community composition). However, the re-establishment of other functions like C sequestration may require more profound recovery of conditions and ecosystem structure. We discuss the potential economic value of restored peatland ecosystems from the perspective of their C sequestration function.

Determination of low-molecular-mass aliphatic carboxylic acids and inorganic anions from kraft black liquors by ion chromatography.

An ion chromatographic (IC) method with suppressed conductivity detection (CD) was developed and validated for the quantitative determination of several low-molecular-mass aliphatic mono- and dicarboxylic acids as their carboxylate anions together with some inorganic anions (chloride, sulfate, and thiosulfate) from kraft black liquors. To confirm the identification of some carboxylate anions which lack commercial model substances, a qualitative IC method with suppressed electrospray ionization mass spectrometry (ESI-MS) was also developed. The separations were performed on an IonPac AS 11-HC anion-exchange column operated at 25 degrees C within 25 min by a gradient elution with aqueous potassium hydroxide (suppressed CD in the AutoRegen mode) or sodium hydroxide (suppressed ESI-MS in the pressurized bottle mode). In the validation process a mixture of carboxylic acids and inorganic anions in aqueous media and in seven different types of wood and non-wood black liquor samples were quantitatively analyzed by IC-CD. As a result, calibration lines with correlation coefficients of 1.00 for all analytes were achieved at a concentration range from 0.05 to 105 mg L(-1). In black liquor samples intra-day (n=6) precision values ranged from 0.9 to 5%. Day-to-day (n1=3) and intermediate precision values were less than 5% for all other compounds except sulfate and thiosulfate. The variability in the thiosulfate and sulfate results is due in large part to the oxidation of sulfide and thiosulfate, respectively. Recoveries were close to 100% with standard deviations less than 8%. Depending of the analyte, the limits of detection and quantification were, respectively, between 1 and 8 microg L(-1) and between 3 and 27 microg L(-1) for standard compounds in aqueous media and between 6 and 106 microg L(-1) and between 14 and 148 microg L(-1) for black liquor samples. These validation results clearly indicated that with respect to selectivity, linearity, limits of detection and quantification, precision, and accuracy, the IC-CD method showed good applicability in the determinations described above.

Determination of alternative and conventional chelating agents as copper(II) complexes by capillary zone electrophoresis--the first use of didecyldimethylammonium bromide as a flow reversal reagent.

A capillary zone electrophoresis (CZE) method for analyzing 11 chelating agents [beta-alaninediacetic acid (beta-ADA), trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), N-(2-hydroxyethyl)iminodiacetic acid (HEIDA), iminodiacetic acid (IDA), methylglycinediacetic acid (MGDA), nitrilotriacetic acid (NTA), 1,3-diaminopropane-N,N,N',N'-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)] as negatively charged copper(II) complexes has been established. Both conventional and alternative chelating agents were included in this study, because they are used side by side in industrial applications. In this study, didecyldimethylammonium bromide (DMDDAB) was successfully used as a flow reversal reagent for the first time in an aqueous CZE method based on phosphate BGE with UV spectrophotometric detection. In addition this new flow modifier was compared to common TTAB. Method development was done using a fused silica capillary (61 cm x 50 microm i.d.). The optimized BGE was a 105 mmol L(-1) phosphate buffer with TTAB or DMDDAB in the concentration 0.5 mmol L(-1) at pH 7.1. The measurements were done with -20 kV voltage using direct UV detection at 254 nm. In both CZE methods all 11 analyte zones were properly separated (resolutions > or =2.4), and the calibrations gave excellent correlation coefficients (> or =0.998; linear range tested 0.5-2.0 mmol L(-1)). The limits of detection were < or =34 and < or =49 micromol L(-1) with the method of DMDDAB and TTAB, respectively. A clear benefit of both methods was the short analysis time; all 11 complexes were detected in less than 6 and 5.5 min with the methods of TTAB and DMDDAB, respectively. The two methods were tested with dishwashing detergents and paper mill wastewater samples and proved to be suitable for practical use.

Quantitative determination of the main aliphatic carboxylic acids in wood kraft black liquors by high-performance liquid chromatography-mass spectrometry.

The versatile characterization of organic material and especially of the significant aliphatic hydroxy acids in black liquor is of great importance, for example, in monitoring the progress of the kraft pulping process. This paper describes a simple high-performance liquid chromatographic separation method with atmospheric-pressure chemical ionization mass spectrometry (HPLC-APCI-MS) which was developed for the rapid quantitative analysis of these acids, mainly formed as the alkaline degradation products of feedstock carbohydrates. The fraction of carbohydrate degradation products is mainly composed of hydroxy monocarboxylic and volatile acids (formic and acetic acids) along with lesser amounts of various dicarboxylic acids. This method was thoroughly tested and validated to determine the most abundant nonvolatile low-molecular-mass aliphatic mono- and dicarboxylic acids present in softwood (pine and spruce) and hardwood (birch and aspen) kraft black liquors. This straightforward technique provides, compared to the conventional gas chromatographic methods, some important advantages such as simple sample preparation and a faster analysis time, thus enabling almost real-time monitoring of these acids.

Improving sensitivity in simultaneous determination of copper carboxylates by nonaqueous capillary electrophoresis.

A new method of nonaqueous capillary electrophoresis (NACE) with UV spectrophotometric detection was developed and optimized for the simultaneous determination of seven carboxylates (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), nitrilotriacetic acid (NTA), 1,3-diaminopropane-N,N,N',N'-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. The method development was carried out by using a fused silica capillary. Background electrolyte (BGE) was optimized and the best separation achieved by using 30mmolL(-1) potassium bromide in N-methylformamide (NMF) at apparent pH (pH(app)) 10.2. A voltage of +30kV and direct UV detection at 280nm were used in all measurements. Large-volume sample stacking using the electroosmotic flow pump (LVSEP) was tested in addition to basic capillary electrophoresis (CE) and observed to improve the separation of the analyte zones in the capillary. All the peaks in the electropherograms were properly separated, the calibration plots gave excellent correlation coefficients (R(2)>or=0.994) and all seven copper carboxylate complexes were detected in less than 20min using both the basic measurements and the large-volume sample stacking method. The new NACE method was tested with lake water and proved to be reliable.

Separation of chelating agents as copper complexes by capillary zone electrophoresis using quaternary ammonium bromides as additives in N-methylformamide.

This study presents the use of quaternary ammonium bromides as additives in N-methylformamide (NMF) for the separation and quantification of chelating agents as copper complexes by capillary zone electrophoresis (CZE). The new quaternary ammonium bromides were synthesized in our laboratory and used for the first time for CZE applications performed in NMF media. The methods were developed and optimized for determination of six chelating agents (trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid (HEDTA), nitrilotriacetic acid (NTA) and triethylenetetraaminehexaacetic acid (TTHA)) as copper complexes. Among the tested electrolyte additives in NMF media (pH(app) 10.2) dimethyldioctylammonium bromide (DMDOAB), dimethyldinonylammonium bromide (DMDNAB) and dimethyldidecylammonium bromide (DMDDAB), at a concentration of 20 mmol L(-1) improved the separation of the copper complexes. The optimized methods require only 12 min for one analysis, and the detection limits for copper complexes of DMDNAB, the best-performing additive, were < or =24 micromol L(-1). Relative standard deviations (R.S.D.) for migration times were < or =2.5, < or =2.1, < or =3.1% and for peak areas, < or =3.1, < or =3.0, < or =3.2% for DMDOAB, DMDNAB and DMDDAB used as additives, respectively. All three methods were successfully applied to the analysis of natural and wastewater samples. No matrix effects from these samples were observed. The interaction between quaternary ammonium bromides and copper complexes is discussed.

A new ionic liquid dimethyldinonylammonium bromide as a flow modifier for the simultaneous determination of eight carboxylates by capillary electrophoresis.

Two new methods of capillary zone electrophoresis based on aqueous phosphate running buffers with UV spectrophotometric detection were developed and optimized for the determination of eight carboxylates as copper complexes. Metalcomplexes are negatively charged, so measurements were made as anion analyses with flow reversal in the capillary. Two flow modifiers were used: a common tetradecyltrimethylammonium bromide (TTAB) and a new ionic liquid dimethyldinonylammonium bromide (DMDNAB). The methods were compared to each other. Better separation was achieved with DMDNAB as the flow modifier. Method development was done using a fused silica capillary (61 cm x 50 microm i.d.). Optimization was done using 95 mmol L(-1) phosphate buffer with TTAB or DMDNAB in the concentration 0.5 mmol L(-1) at pH 7.1. A -20 kV voltage and direct UV detection at 254 nm was used in measurements. In both CE methods all the peaks in the electropherograms were properly separated, the calibration plots gave good correlation coefficients and all eight carboxylates were detected in less than 7.5 min. The two methods were tested with natural water samples and a paper mill sample, and proved to be feasible.

Simultaneous determination of DTPA, EDTA, and NTA by UV-visible spectrometry and HPLC.

In this study, UV-visible spectrophotometry (UV-Vis) and high-performance liquid chromatography (HPLC) were used for simultaneous analysis of chelating agents diethylenetriamine pentaacetic acid (DTPA), ethylenediamine tetraacetic acid (EDTA), and nitrilotriacetic acid (NTA), as their metal chelates in dishwashing detergents, natural waters, and pulp mill water. The total amounts of the chelating agents in dishwashing detergents were verified by potentiometric titration with Fe(III) solution. Nickel(II) chelates were determined by UV-Vis and iron(III)chelates by HPLC and titration. Recoveries of DTPA, EDTA, and NTA from a standard mixture of analytes by UV-Vis were 107+/-7, 101+/-12 and 94+/-13%, respectively, and the recovery of the total amount of complexing agents was 99+/-4%. The limits of detection for DTPA, EDTA, and NTA were 667, 324, and 739 micromol L(-1), respectively. In HPLC measurements the optimized mobile phase contained 0.03 mol L(-1) sodium acetate, 0.002 mol L(-1) tetrabutylammonium bromide, and 5% methanol at pH 3.15 and the detection was by UV-Vis detection at 254 nm. All three complexing agents could be separated from each other in a simultaneous analysis in less than 5 min. The limits of detection were 0.34, 0.27, and 0.62 micromol L(-1) for DTPA, EDTA, and NTA, respectively. The total amounts of the analytes measured in the dishwashing detergents by the three techniques were found to be highly comparable (ANOVA: F=0.04, P=0.96). R(2) values were 0.99 for EDTA, 0.99 for NTA, and 0.99 for all the results when UV-Vis and HPLC determinations were compared using regression lines. The UV-Vis and HPLC methods were proved to be viable also for analyses of natural and pulp mill waters. The absence of matrix interferences was verified by the standard addition technique.

Simultaneous determination of DTPA, EDTA, and NTA by capillary electrophoresis after complexation with copper.

We present a method for simultaneous determination of the aminopolycarboxylic acids DTPA, EDTA and NTA in dishwashing detergents, paper mill waters, and natural waters by capillary electrophoresis (CE). The complexing agents were examined as their copper(II) complexes and separated by conventional CE with reversed polarity of the applied voltage. The optimum separation conditions were established by varying the pH and phosphate and tetradecyltrimethylammonium bromide (TTAB) concentrations in the run buffer. The separations were carried out in a fused-silica capillary (61 cmx75 microm i.d.) filled with phosphate buffer (80 mmol L(-1), TTAB concentration 0.5 mmol L(-1), pH 7.1, voltage -20 kV) using direct UV detection at 191 and 254 nm. With this CE method all the peaks in the electropherograms were properly separated, the calibration plots gave good correlation coefficients and all three complexing agents could be detected in less than 4 min. Linear calibration plots were obtained for CuDTPA, CuEDTA and CuNTA; limits of detection were 0.03 mmol L(-1) for all complexing agents and recoveries for all tested samples were within the range 104+/-7%. Results obtained from dishwashing detergent samples were found to be reliable and comparable with those from HPLC (R2=0.989) and UV-Vis (R(2)=0.985) methods.