One-Hour Screening of Adulterated Heparin by Simplified Peroxide Digestion and Fast RPIP-LC-MS²

Early detection of potential contaminants in heparin, an extensively used anticoagulant in drug formulations and medical devices, is critical to ensuring public health. In response to heparin adulteration by oversulfated chondroitin sulfates (OSCS) that was associated with adverse events including deaths in 2007–2008, many methods have been developed to detect OSCS in heparin. However, an analytical challenge for quality screenings has been to speed up these measurements to address the complex distribution scheme of heparin in today’s global market. Here an approach based on mass spectrometry is described that enables the measurement of adulterated heparin in 1 h, significantly shortening the time frame of screening for potential contaminants. The methodology is based on simplified peroxide digestion that rapidly depolymerizes large polysaccharide chains to small oligosaccharides followed by fast liquid chromatography mass spectrometry to determine sample purity. We find that rapid peroxide digestion generates abundant C- and Y-type oligosaccharides that can be used to differentiate parent glycosaminoglycans via unsupervised multivariate analysis, including heparin, chondroitin sulfate A, dermatan sulfate, and the infamous OSCS. With quantitation demonstrated at 1% (w/w), or 50 ng, OSCS in heparin and the lower limit of detection estimated at ∼0.20% (w/w), or ∼10 ng, OSCS in heparin, the technology was sufficiently sensitive to differentiate real-life, “authentic” adulterated heparin samples and to quantify this contaminant with an error <10% relative standard deviation. The methodologies presented here are deliberately simple to foster adoption and increase the analytical throughput of mass spectrometric screening in the routine quality assessment of heparin and other types of compounds of this molecular family

Additional file 1: of Liuzijue Qigong vs traditional breathing training for patients with post-stroke dysarthria complicated with abnormal respiratory control: study protocol of a single center randomized controlled trial

SPIRIT 2013 Checklist. (DOCX 55 kb

Additional file 2: of Liuzijue Qigong vs traditional breathing training for patients with post-stroke dysarthria complicated with abnormal respiratory control: study protocol of a single center randomized controlled trial

Table S1. Primary and secondary objectives as well as their related statistical methods. The new table contains a short overview of indicators, used evaluation methods, and types of data and statistical methods for analyzing primary and secondary study objectives. (DOCX 15 kb

Synthesis of WS₄^2– Intercalated NiZnAl LDHs as Effective Adsorbents to Remove Copper Ions from Water

A series of WS42– intercalated NiZnAl ternary-layered double-hydroxides (LDHs) with various Ni/Zn ratios were synthesized by an ion-exchange method and used as adsorbents to remove Cu2+ from water. The introduction of Zn produced ZnS on the surface of LDHs. The LDH with the Ni/Zn/Al molar ratio of 0.1/1.9/1 showed the best adsorption ability. Cu2+ ions are removed via three routes: forming [Cu–WS4]n− complexes via soft acid–soft base interaction between WS42– and Cu2+, isomorphic substitution of Zn2+ in sheets by Cu2+, and cation exchange of Cu2+, with ZnS on the surface of LDHs. With the increased Cu2+ concentration, the complexes dominated the adsorption because polynuclear [Cu–WS4]n− complexes with high Cu/W ratios (2–6) may be formed. Cu+ is present in such complexes, which is produced by the internal redox. Even at Cu2+ concentration up to 600 mg·L–1, neither amorphous CuWS4 nor decreased interlayer distance was observed. Contrarily, the interlayer distance was slightly enlarged due to forming bigger [Cu–WS4]n− complexes. The adsorption followed the pseudo-second-order kinetics and Langmuir isotherm model. The experimental maximum adsorption capacity reached 555.4 mg·g–1

The size distribution histogram of the MS.

<p>The size distribution histogram of the MS.</p

The release profile of the MS in PBST (pH = 7.40).

<p>The release profile of the MS in PBST (pH = 7.40).</p

Antimicrobial activity against Escherichia coli of the native BF-30 and the peptide released from the microspheres on the 1^st,10^th, 11^th, and 12^th days.

<p>Antimicrobial activity against Escherichia coli of the native BF-30 and the peptide released from the microspheres on the 1^st,10^th, 11^th, and 12^th days.</p

Morphology of peptide-loaded PLGA MS.

<p>(a) High magnification, (b) low magnification.</p

Cytotoxicity of the MS. PBST was used as the negative control.

<p>Cytotoxicity of the MS. PBST was used as the negative control.</p

The elution curves of (a) the native BF-30 and (b) the peptide released on the 11th day, (c) the peptide released on the 10^th day.

<p>The elution curves of (a) the native BF-30 and (b) the peptide released on the 11th day, (c) the peptide released on the 10^th day.</p