A sensitive dispersive micro solid-phase extraction coupled with high performance liquid chromatography for determination of three flavonoids in complex matrics by using crab shell as a sorbent.

A sensitive dispersive micro solid-phase extraction coupled with HPLC has been developed for preconcentration and determination of three flavonoids (quercetin, kaempferol, and isorhamnetin) in complex matrix samples. Parameters that affect extraction efficiency have been optimized. The optimal extraction conditions are using 2 µg/mL of crab shell as the sorbent, extraction for 2 min at pH 7, and then eluting with 100 µL of methanol. As a result, the method shows good linearity (R > 0.9994), low LODs (even 0.08 ng/ml) and satisfactory recovery in real honey and rat urine samples. As an eco-friendly biomaterial, crab shell powder is used as sorbent in pretreatment of flavonoids, and its adsorption mechanism has been investigated for the first time. Compared with the other reported methods, the proposed strategy is time-saving, eco-friendly, and highly sensitive using HPLC (even achieving MS grade sensitivity).

An insight into the determination of trace levels of benzodiazepines in biometric systems: Use of crab shell powder as an environmentally friendly biosorbent.

A vortex assisted dispersive solid phase extraction approach (VADSPE) based on crab shell powder as biodegradable and biocompatible µ-sorbent was developed for simultaneous analysis of three benzodiazepines (BZPs): Oxazepam, Flurazepamand Diazepam, in biological matrixes included blood, nail, hair and urine samples. The effective parameters in VADSPE process, including the volume of uptake solvent, the dosage of sorbent, extraction time and back extraction time, were optimized using response surface methodology(RSM) based on central composite design(CCD). The suggested technique allows successful trapping of BZPs in a single-step extraction. Under the optimized extraction conditions, the proposed approach was exhibited low limits of detection (0.003-1.2 µg·mL-1), an acceptable linearity (0.04-20 µg·mL-1). Method performance was assessed by recovery experiments at spiking levels of 10 µg·mL-1(n = 5) for BZPs in blood, nail, hair and urine samples. Relative recoveries were determined by HPLC, which were between 36%and 95.6%.

Effects of bean dregs and crab shell powder additives on the composting of green waste.

Composting is an effective and economic technology for the recycling of organic waste. In this study, bean dregs (BD) (at 0, 35, and 45%) and crab shell powder (CSP) (at 0, 15, and 25%) were evaluated as additives during the two-stage composting of green waste (GW). The GW used in this experiment mainly consisted of branch cuttings collected during the maintenance of the urban green landscape. Combined additions of BD and CSP improved composting conditions and compost quality in terms of composting temperature, specific surface area, average pore diameter, pH and EC values, carbon dioxide release, ammonia and nitrous oxide emissions, E4/E6 ratio, elemental composition and atomic ratios, organic matter degradation, microbial numbers, enzyme activities, compost phytotoxicity, and environmental and economic benefits. The combined addition of 35% BD and 25% CSP to the two-stage composting of GW resulted in the highest quality compost product in only 22 days.